31st International Symposium on Lepton Photon Interactions at High Energies

17 Jul 2023, 08:30 → 21 Jul 2023, 18:00 Australia/Melbourne

Monash University

Ulrik Egede (Monash University (AU))

The 31st International Symposium on Lepton Photon Interactions at High Energies will be hosted by Monash University in Melbourne.

The programme covers a wide range of topics of interest to the particle physics community spanning results from current experiments, R&D towards future facilities, theoretical developments, and contributions on inclusion, diversity, and public engagement. In addition to the core plenary talks, there will also be parallel and poster sessions.

Abstract submission closed.

Local organising committee

• Ulrik Egede, Monash University, Australia  (chair)
• Tom Hadavizadeh, Monash University, Australia 
• Peter Skands, Monash University, Australia 
• Yuki Fujii, Monash University, Australia 
• Geman Valencia, Monash University, Australia 
• Csaba Balasz, Monash University, Australia 
• Irene Bolignoni, University of Adelaide, Australia 
• Peter Cox, University of Melbourne, Australia 
• Paul Jackson, University of Adelaide, Australia 
• Michal Kreps, Warwick University, UK

International Advisory Committee

• Jenni Adams,  University of Canterbury, New Zeeland
• Takashi Kobayashi, KEK, Japan
• Joseph Lykken, FNAL, USA
• Azwinndini Muronga, Nelson Mandela University, South Africa
• Beate Heinemann, DESY, Germany
• Florencia Canelli, University of Zurich, Switzerland
• Marco Serone, SISSA, Italy
• Suchita Kulkarni, University of Graz, Austria
• Tatsuya Nakada, EPFL, Switzerland
• Yifang Wang, IHEP, China
• Fabiola Gianotti, CERN
• Else Lytken, Lund University, Sweden
• Marie-HélèneSchune, IJCLab, France
• Martha Hilton, Manchester University, UK

Monday 17 July

08:30 → 09:30 Welcome, closing and society

Convener: Ulrik Egede (Monash University (AU))

08:55 Welcome

Speaker: Ulrik Egede (Monash University (AU))

LP23welcome.pdf

09:00 Welcome to country

09:15 Indigenous culture as part of a University

Speaker: Prof. Tristan Kennedy (Monash University)

09:30 → 10:30 Neutrino

Convener: Francesca Di Lodovico (University of London (GB))

09:30 CP violation searches in neutrino oscillations

Speaker: Prof. Christopher Mauger (University of Pennsylvania (US))

Mauger-LeptonPhoton2023-CPVio-July2023v4.pdf

10:00 km baseline neutrino experiments

Speaker: Liang Zhan (Institute of High Energy Physics)

KmBaselineNeutrinoExperiment_LiangZhan.pdf

10:30 → 11:00 Morning break

11:00 → 12:30 Collider Precision

Convener: Jordan Nash (Monash University)

11:00 SM precision measurements

Speaker: Joao Barreiro Guimaraes Da Costa (Chinese Academy of Sciences (CN))

Lepton-Photon-SM Physics-Joao-Guimaraes-20230717.pdf

11:30 Standard Model prediction uncertainties

Speaker: Dr Xuan Chen (Universitaet Zuerich (CH))

LeptonPhoton2023XuanChen.pdf

12:00 Higgs properties

Speaker: Linda Finco (INFN Torino (IT))

HiggsProperties_LP_Finco_AtlasMass.pdf

12:30 → 13:30 Lunch

13:30 → 15:00 Low energy

Convener: Yuki Fujii (Monash University (AU))

13:30 Theory behind making Electric Dipole measurements

An overview of the search for permanent electric dipole moments in atoms and molecules will be given, with a particular focus on the theory that connects the measurements in atoms and molecules to fundamental CP-violating parameters.

Speaker: Jacinda Ginges (The University of Queensland)

Lepton-Photon_Ginges.pdf

14:00 EDM experimental measurements

The imbalance of matter and anti-matter in our universe provides compelling motivation to search for new particles that violate CP symmetry. The fields associated with the hypothetical new particles would interact with Standard Model particles, giving them CP-violating electric dipole moments (EDMs). In this talk, I will present the most precise measurement yet of the electron’s EDM using electrons confined inside molecular ions, subjected to a huge intra-molecular electric field, and evolving coherently for up to 3 s. Our sensitivity to $10^{-19}$ eV shifts in the molecular energy levels provides constraints on broad classes of new physics above $10^{13}$ eV.

Speaker: Luke Caldwell

luke-caldwell-slides-17-Jul-23.pdf

14:30 Charged lepton flavour violation

Speaker: Yoshitaka KUNO

LP2023-KUNO.pdf

15:00 → 15:30 Afternoon break

15:30 → 17:30 Flavour

Convener: Martin Sevior

15:30 Heavy flavour spectroscopy

This talk will provide an overview of recent results on the hadrons with heavy quarks, especially the candidates of exotic states observed at the BESIII, Belle, Belle II, and the LHC experiments.

Speaker: Changzheng YUAN

Yuan_HFspectroscopy_LP.pdf

16:00 Lattice QCD developments in flavor physics

Speaker: Ying CHEN

cheny-LP23.pdf

16:30 Searches for NP in rare hadron decays

Speaker: Matteo Rama (INFN Pisa (IT))

RareHadronDecays_Rama.pdf

17:00 Fits to measurements in rare heavy flavour decays

We shall review some salient features of the data in rare B-meson hadron decays. We shall then discuss fits of various effective field theories which can explain current data.

Speaker: Prof. Ben Allanach (University of Cambridge (GB))

lepton_photon.pdf

17:30 → 19:00 Reception and poster presentation

17:30 Hunting for heavy neutral leptons at future lepton colliders

Neutrinos are the most elusive particles known. Heavier sterile neutrinos mixing with the Standard Model partners might solve the mystery of the baryon asymmetry of the universe and take part in the mass generation mechanism for the light neutrinos. Future lepton colliders, including $e^+e^-$ Higgs factories, as well as multi-TeV electron and muon machines, will provide the farthest search reach for such neutrinos in the mass range from above the $Z$ pole into the multi-TeV regime. In our contribution, we will discuss the future lepton collider search potential for such particles in their prompt decays. We will also present a new approach to use kinematic variables to constrain the nature of heavy neutrinos, probing their Majorana or Dirac character. Finally, we will discuss the complementarity in the flavor-mixing parameter space between the two types of lepton colliders.

Speaker: Mr Krzysztof Mekala

17:31 Engaging Universities and Beyond – Open Data for Education and Research

The ATLAS Open Data project has for many years successfully delivered open-access data, simulations, documentation and related resources for education and outreach use in High Energy Physics and related computer sciences based on data collected in proton–proton collisions at 8 TeV and 13 TeV. These resources have found substantial application worldwide in Universities, in Schools, and in other public settings. Building on this success and in support of CERN’s Open Data Policy the ATLAS experiment plans to continue to release 13 TeV data for educational purposes and – for the first time – also for research purposes. This contribution will summarise the landscape of the existing ATLAS Open Data project: what resources are available and how have they been used, and what is planned for the future.

Speaker: Darren Price (University of Manchester (GB))

dprice_ATLASOpenData_LP23.pdf

17:32 Evolution of Regional, Age and Gender Demographics in the ATLAS Collaboration

The ATLAS Collaboration consists of more than 5000 members, from over 100 different countries. Regional, age and gender demographics of the collaboration are presented, including the time evolution over the lifetime of the experiment. In particular, the relative fraction of women is discussed, including their share of contributions, recognition and positions of responsibility, including showing how these depend on other demographic measures.

Speaker: Heather Gray (UC Berkeley/LBNL)

LeptonPhotonPosterHgray.pdf

17:33 High precision study of antineutron and hyperons interact with nuclei at a future super J/ψ factory

Physicists investigate the subatomic world by bombarding their subject of study with a hail of tiny subatomic “bullets”. From the way these “bullets” bounce off their target one can infer a wealth of detailed information about the target’s structure. Different kinds of subatomic “bullets” probe different aspects of the target, certain important aspects of the force holding atomic nuclei together can only be investigated by shooting particles called antineutrons and hyperons, which are believed to be very difficult to produce and control. However these usually rare particles can be produced in copious amounts and easily launched as a spinoff of a “super J/ψ factory”. This opens fresh research opportunities in particle and nuclear physics, as well as in astrophysics and medical physics, requiring no additional infrastructure.

Speaker: Weimin Song (Jilin University College of Physics (CN))

17:34 Overview of the event reconstruction in JUNO

Jiangmen Underground Neutrino Observatory (JUNO), located in the southern part of China, will be the world’s largest liquid scintillator (LS) detector upon completion. Equipped with 20 kton LS, 17612 20-inch PMTs and 25600 3-inch PMTs in the central detector, JUNO will provide a unique apparatus to probe the mysteries of neutrinos, particularly the neutrino mass ordering puzzle. One of the main challenges for JUNO is the high precision event reconstruction. This talk will give an overview of the event reconstruction in JUNO, including PMT waveform reconstruction, vertex and energy reconstruction for reactor anti-neutrinos, track reconstruction for cosmic muons as well as directionality reconstruction and flavor identification for atmospheric neutrinos. Hopefully the novel ideas and techniques presented in this talk could shed light on enhanced detector performance for other experiments.

Speaker: Wuming Luo (Institute of High Energy Physics, Chinese Academy of Science)

LP2023poster.pdf

17:35 Hyperon physics at BESIII

With the large data sets of $e^+e^-$ annihilation at the $J/\psi$ and $\psi(3686)$ resonances collected by the BESIII experiment, multi-dimensional analyses making use of polarisation and entanglement can shed new light on the production and decay properties of hyperon-antihyperon pairs. In a series of recent studies performed at BESIII, significant transverse polarization of the (anti)hyperons has been observed in $J/\psi$ or $\psi(3686)$ $\to$ hyperon anti-hyperon pairs. The decay parameters for the most common hadronic weak decay modes were measured, and due to the non-zero polarisation, the parameters of hyperon and antihyperon decays could be determined independently of each other for the first time. Comparing the hyperon and antihyperon decay parameters yields precise tests of direct CP-violation that complement studies performed in the kaon sector.

Speaker: Yunlong Xiao (Fudan University)

Lepton_Photon_Yunlong.pdf

17:36 A History of Queer Contributions to Physics

The contributions of LGBTQIA+ people to the scientific endeavour have been minimised and historically erased. This problem is especially acute in physics where discrimination and poor representation have contributed to a lack of LGBTQIA+ people in the field. In this work, we analyse the historic contributions of LGBTQIA+ people to physics research and education, using a sexually discursive and performative gender framework. This framework highlights the importance of contextual factors when assessing historical gender and sexuality allowing for a nuanced assessment of these identities. These contributions highlight the historical and ongoing importance of LGBTQIA+ scientists to physics research and education.

Speaker: Eliot Jane Walton (Monash University (AU))

Lepton_Photon_AQHiS_štiri.pdf

17:37 Development of a Cylindrical Trigger Hodoscope for the COMET experiment

Charged lepton flavour violation (CLFV) provides an experimental probe into new physics beyond the Standard Model. The COMET experiment at J-PARC in Tōkai, Japan will be using the highest intensity muon beam yet to search for muon to electron conversion, a CLFV process, with the best sensitivity so far. Taking a staged approach to this search, Phase-I of COMET will begin in 2024 with a planned single event sensitivity of $3\times10^{-15}$. In order to reach this sensitivity, a cylindrical trigger hodoscope detector (called the CTH detector) is being developed in order to trigger on high momentum electrons coming from conversion events. The CTH detector will be capable of operating in a high hit rate, high radiation environment. This presentation will give an overview on the development of the CTH detector scintillator counters and readout electronics, as well as performance tests undertaken on these counters at the Australian Synchrotron.

Speaker: Sam Dekkers

LeptonPhotonPosterFinalv2.pdf

17:38 The CMS tracker performance in Run3

The innermost tracking system of the CMS experiment consists of two tracking devices, the Silicon Pixel and Silicon Strip detectors. The tracker was specifically designed to very accurately determine the trajectory of charged particles or tracks.

In this talk, the preliminary performance of the tracker detectors during the Run 3 operation will be summarized, with particular emphasis on the expected changes in detector performance with increasing irradiation.

Speaker: Muti Wulansatiti (Florida State University (US))

PrintCMSTrackerPerformancePosterFinalMW.pdf

17:39 Isospin splitting and quark charge screening effects on M1 decay widths of charm baryons

In light of the precise experimental measurements of the heavy flavor baryons, we calculate the isospin mass splitting of charm baryons by incorporating isospin symmetry breaking. We obtain the masses of $J^P=\frac{1}{2}^{(\prime) +}$ and $\frac{3}{2}^+$ charm baryons utilizing the effective mass scheme based on single gluon exchange interaction between the spectator quarks inside the baryons. In addition, we analyze the modification of quark charge by employing screening effect caused by the neighboring quarks. Consequently, we obtain the magnetic and transition moments of $J^P=\frac{1}{2}^{(\prime) +}$ and $\frac{3}{2}^+$ baryons to predict radiative M1 decay widths for $\frac{1}{2}^{\prime +} \to \frac{1}{2}^+$ and $\frac{3}{2}^+ \to \frac{1}{2}^{(\prime) +}$ transitions.

Speaker: Thejus Mary S

poster.pdf

17:40 Machine learning based classifications on FPGAs

In modern high energy physics experiments, one of the biggest challenges is handling an enormous amount of data in a short time period. This is important to achieve higher statistics while keeping the modest data throughput rate with sustainable resources. In COMET Phase-I, which is searching for the muon to electron conversion with a highly intense muon beam, we are going to implement the machine learning based classifications in order to perform a primary event selection with high precision with a fast processing time at the level of sub-microseconds. Recently, we successfully implemented a simple neural network into the commercial middle-end FPGA and evaluated the classification performance. We will report the result and future prospects.

Speaker: Yuki Fujii (Monash University (AU))

LP2023Poster.pdf

17:41 TopicFlow: Disentangling quark and gluon jets with normalizing flows

The isolation of pure samples of quark and gluon jets is of key interest at hadron colliders. Recent work has employed topic modeling to disentangle the underlying distributions in mixed samples obtained from experiments. However, current implementations do not scale to high-dimensional observables as they rely on binning the data. In this work we introduce TopicFlow, a method based on normalizing flows to learn quark and gluon jet topic distributions from mixed datasets. These networks are as performant as the histogram-based approach, but since they are unbinned, they are efficient even in high dimension. The models can also be oversampled to alleviate the statistical limitations of histograms. As an example use case, we demonstrate how our models can improve the calibration accuracy of a classifier. Finally, we discuss how the flow likelihoods can be used to perform outlier-robust quark/gluon classification.

Speaker: Ayodele Ore

17:42 A Bayesian dark matter analysis pipeline for CTA

The Cherenkov Telescope Array (CTA) is poised to revolutionise gamma-ray astronomy. One of the key science goals of CTA is the detection of gamma rays from dark matter annihilation. In this talk, I will describe a new Bayesian pipeline for the detection of dark matter using CTA data. The pipeline builds on top of the popular Gammapy package. The dark matter signal model is described in terms of a prior for the distribution of sky location and gamma-ray energy. Different dark-matter scenarios can be compared using Bayesian model selection. It is possible to marginalise over systematic errors associated with the signal model or the detector response. I discuss the benefits of this approach, and present some preliminary results obtained with mock data of the galactic centre.

Speaker: Liam Pinchbeck (School of Physics and Astronomy - Monash University)

17:43 Higgs boson mass measurement at CMS

The detailed methodology and results of CMS for the most recent Higgs boson mass measurements are presented.

Speaker: Andrey Korytov (University of Florida (US))

2023.07.17_Hmass_LP2023_24x36.pdf

17:44 Improving ATLAS Hadronic Object Performance with in situ techniques and ML/AI Algorithms

Experimental uncertainties related to hadronic object reconstruction can limit the precision of physics analyses at the LHC, and so improvements in performance have the potential to broadly increase the impact of results. Hadronic object reconstruction is also one of the most promising settings for cutting-edge machine learning and artificial intelligence algorithms at the LHC. Recent refinements to reconstruction and calibration procedures for ATLAS jets and MET result in reduced uncertainties, improved pileup stability and other performance gains. In this contribution, selected highlights of these developments will be presented.

Speaker: Albert Kong (University of Adelaide (AU))

lep.pdf

17:45 The ATLAS Trigger System

The ATLAS experiment in the LHC Run 3 is recording up to 3 kHz of fully-built physics collision events out of an LHC bunch crossing rate of up to 40 MHz, with additional rate dedicated to partial readout. A two-level trigger system selects events of interest to to cover a wide variety of physics while rejecting a high rate of background events. The selection of events targets both generic physics signatures, such as high pT leptons, jets, missing energy, as well as more specific signatures targeting specific physics, such as long lived particles, or di-Higgs events. We will present an overview of the ATLAS trigger system in Run 3, including improvements to the first level trigger hardware and high level trigger software compared to Run 2, and of the trigger performance in 2022.

Speaker: Luisa Carvalho (LIP (PT))

PosterTriggerRun3_LP2023.pdf

17:47 Neutrino Interactions in the T2K WAGASCI Detector and Combining Measurements With Multiple Neutrino Fluxes

T2K is a long base line neutrino experiment in Japan with a 295 km base line between the JPARC facility, which produces the neutrino beam, and the SuperKamiokande water Cherenkov far detector. T2K has a rich physics programme including a series of world leading neutrino cross-section measurements. The current status of T2K cross-section measurements will be summarised and the future plans of the collaboration will be presented. This includes the prospects of joint measurements using the ND280 near detector, which is along the same 2.5 degree off-axis position as SuperKamiokande, and the 1.5 degree off-axis near detector WAGASCI. A combined cross sections analysis using data at both off-axis angles offers the unique ability to better constrain the flux and cross sections than either data set can accomplish individually. The incorporation of new water target data from the WAGASCI near detector will also be presented.

Speaker: John Columba Nugent (Tohoku University (JP))

lp_jn.pdf

17:48 Charmless b-hadron decays at LHCb

Decays of beauty hadrons to charmless final sates receive relevant contributions from penguin topologies where new physics beyond the Standard Model may appear as virtual contributions. The presence of these new particles can be revealed comparing the branching fractions and CP asymmetries of these decays with the Standard Model expectations. In addition, the combination of several quantities and the study of the decay dynamic over the phase space of multibody decays allow the models used to deal with QCD effects to be validated. In this presentation the most recent analyses of charmless b-hadron decays performed by LHCb are presented.

Speaker: Rongrong Song (Monash University (AU))

17:49 The Progress of Super Tau Charm Facility in China

The proposed STCF is a symmetric electron-positron beam collider designed to provide e+e− interactions at a centerof-mass energy from 2.0 to 7.0 GeV. The peaking luminosity is expected to be 0.5×10^35 cm−2s−1. STCF is expected to deliver more than 1 ab−1 of integrated luminosity per year. The huge samples could be used to make precision measurements of the properties of XYZ particles; search for new sources of CP violation in the strange-hyperon and tau−lepton sectors; make precise independent mea-surements of the Cabibbo angle (theta)c) to test the unitarity of the CKM matrix; search for anomalous decays with sensitivities extending down to the level of SM-model expectations and so on. In this talk, the physics interests will be introduced as well as the the recent progress on the project R&D.

Speaker: Zekun Jia

LPposter.pdf

17:50 The status and the radioactive background control of JUNO’s Water Cherenkov Detector

The Jiangmen Underground Neutrino Observatory (JUNO), a 20 kton multi-purpose low background liquid scintillator detector, was proposed primarily to determine the neutrino mass ordering. To suppress the radioactivity from surrounding rocks and tag the cosmic muons, the central detector is submerged in a water Cherenkov detector (WCD), which is filled with 35 kton ultrapure water and equipped with 2400 MCP-PMTs. To lower the accidental background in the central detector, the radon concentration in the ultra-pure water should be reduced to less than 10 mBq/m3. This talk will introduce WCD’s current status as well as the radon removal and online monitor system.

Speaker: Cong Guo (中国科学院高能物理研究所)

The status and the radioactive background control of JUNO's Water Cherenkov Detector.pdf

17:51 Systems for detecting and measuring backgrounds with the SABRE South experiment

The SABRE (Sodium iodide with Active Background REjection) experiment aims to detect an annual rate modulation from dark matter interactions in ultra-high purity NaI(Tl) crystals which will provide a model independent test of the signal observed by DAMA/LIBRA. It will consist of two separate detectors in the Northern and Southern hemispheres. SABRE South will be located in the newly completed Stawell Underground Physics Laboratory (SUPL), the first deep underground laboratory in the southern hemisphere. As the first large detector in SUPL, SABRE South will also be used to measure backgrounds from radiogenic and cosmogenic sources. SABRE South is intended to disentangle seasonal or site-related effects from the dark matter-like modulated signal and as such measuring and understanding these backgrounds is essential for the reliability and consistent performance of these searches.

SABRE South is designed to detect the signals generated by radiation and cosmic rays using both a 17kL liquid scintillator detector which will be contained in a steel vessel, and a plane of plastic scintillator modules located above the vessel to more reliably detect muons from cosmic-rays. The liquid scintillator is instrumented with 18 PhotoMultiplier Tubes (PMTs) which will be immersed in the liquid. The plastic scintillator has 8 modules each instrumented with 2 PMTs allowing position resolution below 5cm.

During the ongoing construction and commissioning of the final SABRE South experiment, the plastic scintillator system is being used to measure the muon flux at SUPL as a function of energy and angle. In addition the performance of the liquid scintillator has been measured using a small scale setup which combined with dedicated simulation studies allows for particle identification and position reconstruction. To achieve the best identification and reconstruction the behaviour of the PMTs have also been extensively measured and studied.

This talk will report on the capabilities of the liquid and plastic scintillator detection systems including calibration procedures, methods for particle identification and position reconstruction, results of and comparison to Geant4 simulation, as well as the first measurements of muon flux observed by the plastic scintillator system at SUPL.

Speaker: Lachlan Milligan

LeptonPhotonPoster2023LMilligan_Final.pdf

17:53 Engaging Youth - Education and Outreach for ages 0-12

Engaging children under the age of 12 in physics research is particularly challenging but offers unique educational potential. Outreach and engagement at an early age has been demonstrated to be key to increasing awareness of physics and to increasing diversity in the field in later years. We present a variety of activities and resources developed by the ATLAS Collaboration targeting this demographic, including the ATLAS Baby Book, ATLAS Colouring Books, ATLAS Activity Sheets, Lego models and more. We discuss the motivation in the creation of these resources, details of their use, and future plans. We also discuss the status and impact of translating these documents into many languages for truly global engagement.

Speaker: Emily Filmer (University of Adelaide (AU))

EFilmer_LP2023_OUTR.pdf

17:54 The Strong2020 and RadioMonteCarlow activities

During the last 15 years the "Radio MontecarLow" ("Radiative Corrections and Monte Carlo Generators for Low Energies") Working Group, see www.lnf.infn.it/wg/sighad/, has been providing valuable support to the development of radiative corrections and Monte Carlo generators for low energy $e^{+}e^{-}$ data and tau-lepton decays.
Its operation started in 2006 and proceeded until the last few years, bringing together at 20 meetings both theorists and experimentalists, experts working in the field of $e^{+}e^{-}$ physics and partly also the tau community, and produced the report "Quest for precision in hadronic cross sections at low energy: Monte Carlo tools vs. experimental data" S. Actis et al. Eur. Phys. J. C 66, 585-686 (2010) (https://arxiv.org/abs/0912.0749), which has more than 300 citations.
While the working group has been operating for more than 15 years without a formal basis for funding, parts of our program have recently been included as a Joint Research Initiative in the group application of the European hadron physics community, STRONG2020, to the European Union, with a more specific goal of creating an annotated database for low-energy hadronic cross sections in $e^{+}e^{-}$ collisions.
The database will contain information about the reliability of the data sets, their systematic errors, and the treatment of Radiative Corrections. We will report on both these initiatives as well as the effort towards the realization of a Monte Carlo with fully NNLO corrections for low energy $e^{+}e^{-}$ data into hadrons.

Speaker: Mr Lorenzo Cotrozzi

COTROZZI_STRONG2020_POSTER_LP23.pdf

17:55 Characterization of a 180nm CMOS pixel sensor prototypes for the CEPC vertex detector

The proposed Circular Electron Positron Collider (CEPC) imposes new challenges for the vertex detector in terms of pixel size and material budget. A Monolithic Active Pixel Sensor (MAPS) prototype, TaichuPix, based on a column drain readout architecture, has been implemented to achieve high spatial resolution and fast readout.
In December 2022, a beam test system consisting of 6 layer TaichuPix-3 chips was tested in DESY II TB21. The offline analysis results shows the spatial resolution can reach 5um, and detection efficiency is larger 98%. The baseline vertex detector was designed with 6-ladder architecture with double-sided TaiChuPix-3 chips. In order to verify the performance of the baseline vertex detector, another beam test was set up in April 2023. Enough valid data was recodred during the beam data, and the offline analysis is working on progress.

Speaker: Shuqi Li (Chinese Academy of Sciences (CN))

poster_LP2023_Shuqi.pdf

17:56 Searches for BSM physics using challenging and long-lived signatures with the ATLAS detector*

Various theories beyond the Standard Model predict new, long-lived particles with unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures from displaced and/or delayed decays anywhere from the inner detector to the muon spectrometer, as well as those of new particles with fractional or multiple values of the charge of the electron or high mass stable charged particles are all examples of experimentally demanding signatures. The talk will focus on the most recent results using 13 TeV pp collision data collected by the ATLAS detector.

Speaker: Emily Filmer (University of Adelaide (AU))

EFilmer_LP2023_SUSY.pdf

17:57 Higgs physics with ILC

With technically mature design and well understood physics program, ILC is a realistic option for realization of a future Higgs factory. Energy staged data collection, employment of beam polarization and capability to reach a TeV center-of-mass energy, enable unique sensitivity to New Physic's deviations from the Standard Model predictions, also in the Higgs sector. Coupling precisions of the order of 1%and better are necessary to pin down a concrete New Physic's model. Measurement of the Higgs self-coupling as a shaping parameter of the Higgs potential will benefit from the accessibility of high-energy scales (500 GeV and above). Clear environment of e+e- collisions, together with the rising cross-sections of the processes of interest with increasing center-of-mass energy, enable CP properties of the Higgs boson to be probed in numerous production and decay vertices. These and other ILC measurements will be highlighted in this talk.

Speaker: Jan Franciszek Klamka (University of Warsaw (PL))

LP23_Higgs_poster_A2.pdf

17:59 Probing for GeV-TeV Particles in the $U(1)_{T3R}$ BSM Extension from $g{-g}$ Fusion Processes at the LHC

The $U(1)_{T 3R}$ extension of the Standard Model is an attractive formulation that addresses the mass hierarchy between the third and the first two generations of fermions, explains thermal dark matter abundance, and the muon $g - 2$ and $R_{K(*)}$ anomalies. The model contains a dark matter candidate, the $\phi$ particle, and a vector-like quark scalar and vector mediator, the $\chi_u$ particle. We perform a phenomenological study to search for and constrain the parameter space of the $\chi_u$ and $\phi$ particles using gluon-gluon fusion processes at the LHC. In particular, we consider decay modes with $\mu^+\mu^-$ final states and use machine learning to maximize the signal sensitivity. We aim for a $5\sigma$ discovery reach with an integrated luminosity of 3000 fb$^{-1}$.

Speaker: Umar Sohail Qureshi (Vanderbilt University)

18:00 Exploring the impact of LIV at Deep Underground Neutrino Experiment

Lorentz Invariance Violation (LIV) is a fundamental violation of space-time symmetry, implying that physical laws vary under Lorentz transformation. The neutrinos are weakly interacting fundamental particles which can act as a probe for understanding the violation of Lorentz invariance symmetry. Here, we consider intrinsic LIV effects that can exist even in a vacuum. We use an effective field theory known as Standard Model Extension (SME) as a framework to treat the LIV as a small perturbation to the standard matter Hamiltonian. The effective Hamiltonian can be implemented to investigate how the presence of LIV parameters modifies the neutrino oscillation probabilities. We particularly study the effect of CPT-Violating LIV terms on the mass-induced neutrino oscillations.
In this work, we explore the impact of LIV on neutrino oscillation probabilities in matter taking DUNE as a case study. We observe a significant effect on neutrino oscillations in the presence of a non-zero LIV parameter. We further investigate the impact of LIV parameters on the CP-measurement sensitivity at DUNE.

Speaker: Dr Moon Moon Devi (Tezpur University, India)

LIV_poster.pdf

18:03 The ATLAS ITk Strip Detector for the Phase-II LHC Upgrade

The inner detector of the present ATLAS experiment has been designed and developed to function in the environment of the present Large Hadron Collider (LHC). At the ATLAS Phase-II Upgrade, the particle densities and radiation levels will exceed current levels by a factor of ten. The instantaneous luminosity is expected to reach unprecedented values, resulting in up to 200 proton-proton interactions in a typical bunch crossing. The new detectors must be faster and they need to be more highly segmented. The sensors used also need to be far more resistant to radiation, and they require much greater power delivery to the front-end systems. At the same time, they cannot introduce excess material which could undermine tracking performance. For those reasons, the inner tracker of the ATLAS detector was redesigned and will be rebuilt completely. The ATLAS Upgrade Inner Tracker (ITk) consists of several layers of silicon particle detectors. The innermost layers will be composed of silicon pixel sensors, and the outer layers will consist of silicon microstrip sensors. This contribution focuses on the strip region of the ITk. The central part of the strip tracker (barrel) will be composed of rectangular short (~ 2.5 cm) and long (~5 cm) strip sensors. The forward regions of the strip tracker (end-caps) consist of six disks per side, with trapezoidal shaped sensors of various lengths and strip pitches. After the completion of final design reviews in key areas, such as Sensors, Modules, Front-End electronics, and ASICs, a large scale prototyping program has been completed in all areas successfully. We present an overview of the Strip System and highlight the final design choices of sensors, module designs and ASICs. We will summarise results achieved during prototyping and the current status of pre-production and production on various detector components, with an emphasis on QA and QC procedures.

Speaker: Marta Baselga (Technische Universitaet Dortmund (DE))

ITk_strip1.pdf

18:05 A combined study of the exclusive mesonic modes to extract $|V_{ub}|/|V_{cb}|$

The precise estimate of the ratio $|V_{ub}|/|V_{cb}|$ is of utmost importance since it plays an essential role in the determination of the sides of the Unitarity Triangle and is an important ingredient in understanding the CKM picture of the
Standard Model. It can be measured directly or indirectly from the extraction of $|V_{ub}|$ and $|V_{cb}|$ from the respective exclusive and inclusive $b \to u l \nu_l$ and $b \to c l \nu_l$ decays. We have worked on the $b \to u \ell\nu$ modes, for eg. $B\to (\pi,\rho,\omega)\ell\nu_{\ell}$ and $B_s\to K \mu\nu_{\mu}$ for a combined extraction of $|V_{ub}|^{exc}$ and the exclusive $b \to c \ell \nu$ channels for eg. $B(B_s) \to D^{(*)} (D_s^{(*)}) l \nu$ for combined extraction of $|V_{cb}|^{exc}$. There has been a recent measurement of the ratio $BR(B_s \to K \mu \nu)/BR(B_s \to D_s \mu \nu)$ from LHCb which is proportional to $|V_{ub}|^2/|V_{cb}|^2$. Thus, from a simultaneous analysis of $b$ $\rightarrow$ $ul\nu$ and $b$ $\rightarrow$ $cl\nu$ modes in different fit scenarios with or without the inputs on the ratios of the branching fractions in the two bins, we obtain the ratio $|V_{ub}|/|V_{cb}|$. We have also extracted the correlation between $|V_{ub}|$ and $|V_{cb}|$ for different cases and provided the predictions of $\mathcal{BR}(B_s\to K\mu\nu_{\mu})$ and $\mathcal{BR}(B\to (\rho,\omega)\ell\nu_{\ell})$ in the Standard Model in small $q^2$-bins. We find a value for $|V_{ub}|/|V_{cb}|$ which is consistent with the determination from the ratio of partial rates of baryonic decays $\text{BR}(\Lambda_b \to p \mu \nu)/\text{BR}(\Lambda_b \to \Lambda_c \mu \nu)$ from LHCb.

Speaker: Ms Ipsita Ray (IIT Gandhinagar)

18:06 Reconstruction of long-lived particles with the ILD detector at the ILC

In recent years, long-lived particles (LLPs) have been widely considered in a variety of Beyond the Standard Model (BSM) scenarios and in many different experimental searches for new particles. Future $e^+e^−$ colliders, thanks to their clean environment and triggerless operation, offer a unique opportunity to search for such states at sub-TeV energies. Considered in this contribution are promising prospects for LLP searches offered by the International Large Detector (ILD) at the International Linear Collider (ILC), with a Time Projection Chamber (TPC) as the core of its tracking systems, providing almost continuous tracking.

Based on the full detector simulation, we study the possibility of reconstructing decays of heavy LLP at the ILD. We consider a challenging scenario with low mass splitting between LLP and the dark matter candidate, resulting in only a very soft displaced track pair in the final state, not pointing to the interaction point. We consider the soft beam-induced background (from measurable $e^+e^−$ pairs and $\gamma\gamma \to$ hadrons processes), expected to give the dominant background contribution due to a very high cross section, and show the possible means of its reduction. We also present corresponding results for an alternative ILD design, where the TPC is replaced by a silicon tracker modified from the design presented for the Compact Linear Collider detector (CLICdet).

Speaker: Jan Franciszek Klamka (University of Warsaw (PL))

llp_ild_jklamka.pdf

18:08 Design of the Hyper-Kamiokande Outer Detector

Hyper-Kamiokande is a large-scale water Cherenkov neutrino detector with a broad physics programme that is currently under construction in Japan. The detector will comprise of two concentric cylindrical detectors referred to as the inner and outer detectors, ID and OD. The ID will be instrumented with 20” PMTs and mPMTs, and used to detect neutrino interactions. The OD serves a different purpose: as a veto for cosmic muons and other backgrounds. Thanks to the cosmic muon shielding from the rock overburden, it is anticipated the rate of cosmic muons within the Hyper-Kamiokande detector will be ~45 Hz. Therefore, a robust veto system, the OD, is designed to tag these cosmic muon background events to ensure a well-understood signal can be detected within the ID. The OD design consists of 3” PMTs mounted within a wavelength shifting plate. The inner and outer walls of the OD volume will be covered in highly-reflective Tyvek material to ensure maximum reflectivity of the photons and improve detection rates in the PMTs. The detector must maintain a high level of efficiency for the duration of the experiment without intervention and so component failure has also been considered in the design process. This talk will discuss the Hyper-Kamiokande OD design.

Speaker: Menai Lamers James

OD_Poster_Lepton_Photon_5.pdf

18:09 LUXE: A new experiment to study non-perturbative QED and search for new particles in electron-laser and photon-laser collisions

The LUXE experiment (Laser Und XFEL Experiment) is an experiment in planning at DESY Hamburg using the electron beam of the European XFEL. LUXE is intended to study collisions between a high-intensity optical laser pulse and 16.5 GeV electrons from the XFEL electron beam, as well as collisions between the laser pulse and high-energy secondary photons. This will elucidate quantum electrodynamics (QED) at the strong-field frontier, where the electromagnetic field of the laser is above the Schwinger limit. In this regime, QED is non-perturbative. This manifests itself in the creation of physical electron-positron pairs from the QED vacuum, similar to Hawking radiation from black holes. LUXE intends to measure the positron production rate in an unprecedented laser intensity regime. The experiment has received a stage 1 critical approval (CD1) from the DESY management and is finalising its technical design report (TDR). It is expected to start running in 2025/6. An overview of the LUXE experimental setup and its challenges and progress will be given, along with a discussion of the expected physics reach in the context of testing QED in the non-perturbative regime.

Speaker: UNKNOWN UNKNOWN

18:10 R value measurements at BESIII

Using the BESIII detector, the R value has been measured on 14 energy points with the corresponding c.m. energies going from 2.2324 to 3.6710 GeV. The statistical uncertainty of the measured R is less than 0.6%. Two different simulation models, the LUARLW and a new Hybrid generator, have been used and give consistent detection efficiencies and initial-state-radiation corrections.
The accuracy in the R value measurements is better than 2.6% below 3.1 GeV and 3.0% above.

Speaker: Zekun Jia

poster_r_value_2023.pdf

18:11 Measurements of charmonia decays at BESIII

We present recent measurements of charmonia decays from BESIII. Using a sample of 448 million $\psi(3686)$ events, the branching fraction of the decays $\chi_c^J \to \phi \phi$ (J=0,1,2) has been measured with improved precision, and the polarisation parameters of the same decay have been determined for the first time via an helicity amplitude analysis. Using the same data sample, the first evidence of $\eta_c(2S) \to \pi^+ \pi^- \eta$ has been observed in the decay sequence $\psi(3686) \to \gamma \eta_c(2S)$, $\eta_c(2S) \to \pi^+ \pi^- \eta$. The product of the branching fractions of $\psi(3686) \to \gamma \eta_c(2S)$ and $\eta_c(2S) \to \pi^+ \pi^- \eta$ and the individual branching fraction will be presented as well. The process $e^+ e^- \to \eta J/\psi$ at a center-of-mass energy of 3.773 GeV has been observed for the first time, its Born cross-section measured, and the branching fraction of $\psi(3770) \to \eta J/\psi$ has been determined by a combined fit with the cross-sections at other energy points, after considering the interference effect for the first time. Utilising 2700 million $\psi(3686)$ events, the decays $\chi_c^J \to \Omega^+ \Omega^-$ (J=0,1,2) have been observed for the first time with high significance via the radiative decays of $\psi(3686) \to \gamma \chi_c^J$. The relevant branching fractions have also been measured.

Speaker: Yizhou Zhou

LP2023 charmonia decays .pdf

18:12 Crystal background and sensitivity for the SABRE South experiment

The SABRE (Sodium iodide with Active Background REjection) experiment aims to detect an annual rate modulation from dark matter interactions in ultra-high purity NaI(Tl) crystals in order to provide a model independent test of the signal observed by DAMA/LIBRA. It is made up of two separate detectors; SABRE South located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia, and SABRE North at the Laboratori Nazionali del Gran Sasso (LNGS). SABRE South is designed to disentangle seasonal or site-related effects from the dark matter-like modulated signal.

The experiment can host seven NaI(Tl) crystals, each instrumented with two R11065 PhotoMultiplier Tubes (PMTs) which are encapsulated in cylindrical copper enclosures flushed with nitrogen. These are surrounded by an active scintillator medium which provides both passive and active shielding, additionally outside this is further passive shielding to block external radiation.

To achieve the highest sensitivity possible, SABRE is working to produce NaI(Tl) crystals with extremely low background in the (1-6) keVee energy region. In this low energy region radioactive contaminants dominate the signals produced in the crystals but also noise introduced by the photomultipliers and readout system can become dominant at lower energies. Significant work has been undertaken to understand and mitigate the background processes that take into account radiation from detector materials, from both intrinsic and cosmogenic activated processes, and to understand the performance of the crystal system.

This talk will report on the results on the characterisation of and dedicated studies on understanding and reducing noise associated with the SABRE South crystal PMTs and their electronics. The results of a detailed simulation of the expected background due to radioactive contamination of the detector will be shown. The resulting projected sensitivity and the effect of other factors on the sensitivity such as quenching factors will be discussed.

Speaker: William Melbourne (The University of Melbourne)

18:13 The Double Calorimetry System in JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) is located in Jiangmen, Guangdong, China, with an overburden of about 700 meters, and its installation is expected to be completed in 2023. The primary goal of the JUNO experiment is to determine the neutrino mass hierarchy with a significance of 3~4 σ in 6 years of data taking and to precisely measure the mixing parameters.
An unprecedentedly high energy resolution of 3% at 1 MeV is required for this purpose. To achieve this, high optical coverage, large area PMT with high quantum efficiency, high transparency liquid scintillator (LS), and low backgrounds are needed. An independent double calorimetry system consisting of 17612 20-inch large PMTs (LPMTs) and 25600 3-inch small photomultiplier tubes (SPMTs) will provide a total photo-coverage of 78% and improving energy resolution, muon reconstruction, supernova neutrino detection. The performances of both types of PMTs reach the requirements. The photomultipliers are all in the process of being installed on the detector.
This talk will cover the current status of two independent systems, as well as the performance and electronics of both LPMT and SPMT.

Speaker: Dr Bei-Zhen Hu (National Taiwan University)

18:14 The Phase 2 upgrade of the CMS Outer tracker

The Large Hadron Collider at CERN will undergo a major upgrade in the Long Shutdown 2 from 2026-2028. The High Luminosity LHC (HL-LHC) is expected to deliver peak instantaneous luminosities up to 7.5E34/cm2/s and an integrated luminosity in excess of 3000/fb during ten years of operation. In order to fully exploit the delivered luminosity and to cope with the demanding operating conditions, the whole silicon tracking system of the CMS experiment will have to be replaced. The Phase-2 Outer Tracker (OT) will have an increased radiation hardness, a higher granularity, and will be able to cope with larger data rates. A key upgrade of the CMS ​detector is to incorporate the identification of charged particle trajectories in the hardware-based (L1) trigger system. A 40 MHz silicon-based track trigger on the scale of the CMS detector has never before been built; it is a novel handle with potential to not only solidify the ​CMS ​trigger strategy but to enable ​searches for ​​completely new physics ​signatures. To achieve this, each module consists of two closely spaced sensors, which are connected to the same readout chips. The readout chips correlate data from both sensors for a rough transverse momentum measurement. This novel concept allows to keep trigger rates at a sustainable level without sacrificing physics potential. The design of the CMS Phase-2 Outer Tracker, highlights about prototyping activities will be presented.

Speaker: Alessandro Rossi (Universita e INFN, Perugia (IT))

Phase2OT_v2.pdf

18:15 Exploring the cosmological dark matter coincidence using infrared fixed points

The asymmetric dark matter (ADM) paradigm is motivated by the apparent coincidence (5:1 ratio) between the cosmological mass densities of visible and dark matter. However, most ADM models only relate the number densities of visible and dark matter, and do not motivate the similarity in their particle masses. One exception is a framework introduced by Bai and Schwaller, where the dark matter is a confined state of a dark QCD-like gauge group, and the confinement scales of visible and dark QCD are related by a dynamical mechanism utilising infrared fixed points of the two gauge couplings. We built upon this framework by properly implementing the dependence of the results on the initial conditions for the gauge couplings in the UV. In this talk I will discuss the ability of this framework to naturally explain the cosmological mass density coincidence. I identify a set of viable models, and note the features that allow them to naturally relate the masses of the dark baryon and the proton while also avoiding collider constraints on the new particle content introduced.

Speaker: Alex Ritter (The University of Melbourne)

18:16 Nucleon structure functions from a lattice Compton amplitude calculation

The structure of hadrons relevant for deep-inelastic scattering are completely characterised by the Compton amplitude. A direct calculation of the Compton amplitude provides a complementary way to accessing the structure functions on the lattice, circumventing the operator mixing and renormalisation issues of the standard operator product expansion approach.

In this contribution, we focus on our lattice QCD calculation of the forward Compton amplitude and highlight our progress in investigating the nucleon structure functions from first principals.

Speaker: Dr K. Utku Can (The University of Adelaide)

kucan_leptonphoton23.pdf

18:17 PMT pre-calibration for SABRE South

The DAMA experiments have detected a modulating signal compatible with dark matter for 20 years with a combined significance of 12.9σ. A result in tension for a spin independent WIMP with null results from large noble gas experiments. This is the motivation for SABRE (Sodium iodide with Active Background Rejection) South experiment. A NaI(Tl) based replication of the DAMA experiment. It is designed to test the DAMA modulation results using the same NaI(Tl) crystal target readout by 14 Hamamatsu R11065 photomultiplier tubes (PMTs) with a 1 keVee energy threshold.

This poster will report on the photomultiplier characterisation test bench developed for the photomultipliers of SABRE South and preliminary results from the first test batch of PMTs. This includes studies of the single photon response, quantum efficiency, and dark noise. The results of the photomultiplier characterisation are crucial to model and understand the low energy performance of the SABRE South experiment. This is crucial to ensure that SABRE South can provide an accurate and significant measurement of the DAMA signal.

Speaker: Owen Stanley

18:18 Flavour anomalies, Light Dark Matter and rare $B$ decays with missing energy in $L_{\mu}-L_{\tau}$ model

In recent times, several hints of lepton flavour universality violation have been observed in semileptonic B decays, which point towards the existence of New Physics beyond the Standard Model. In this context, we consider a new variant of $U(1)_{L_{\mu}-L_{\tau}}$ gauge extension of Standard Model, containing three additional neutral fermions $N_{e}, N_{\mu}, N_{\tau}$, along with a $(\bar{3},1,1/3)$ scalar Leptoquark (SLQ) and an inert scalar doublet, to study the phenomenology of light dark matter, neutrino mass generation and flavour anomalies on a single platform. The lightest mass eigenstate of the $N_{\mu}, N_{\tau}$ neutral fermions plays the role of dark matter. The light gauge boson associated with $U(1)_{L_\mu-L_\tau}$ gauge group mediates dark to visible sector and helps to obtain the correct relic density. The spin-dependent WIMP-nucleon cross section is obtained in leptoquark portal and is looked up for consistency with CDMSlight bound. Further, we constrain the new model parameters by using the branching ratios of various $b \to sll$ and $b \to s \gamma$ decay processes as well as the lepton flavour non-universality observables $R_{K^{(*)}}$ and then show the implication on the branching ratios of some rare semileptonic $B \to (K^{(*)}, \phi)+$ missing energy, processes. The light neutrino mass in this model framework can be generated at one-loop level through radiative mechanism.

Speaker: Prof. Rukmani Mohanta (University of Hyderabad)

LeptonPhoton-RM.pdf

18:19 Computing and data management for SABRE South

The SABRE (Sodium iodide with Active Background REjection) experiment aims to detect an annual rate modulation from dark matter interactions in ultra-high purity NaI(Tl) crystals in order to provide a model independent test of the signal observed by DAMA/LIBRA. SABRE South is located at the Stawell Underground Physics Laboratory (SUPL), in regional Victoria, Australia.

SABRE South is designed to detect the signals generated by radiation and cosmic rays using both a 17kL liquid scintillator detector which will be contained in a steel vessel, and a plane of plastic scintillator modules located above the vessel to more reliably detect muons from cosmic-rays. In addition the crystal detector can host seven NaI(Tl) crystals to detect potential dark matter signals. As both the backgrounds from the outer detectors and potential signals from the crystal detectors are of interest the data taking strategy for SABRE South is to apply a minimal sustainable selection in DAQ to ensure no data of interest is lost. This is then followed by dedicated event building, a final software trigger step and further data reduction using the main SABRE South computing systems. SUPL is a newly constructed facility and as the first experiment, the SABRE computing infrastructure also needs to manage the data transfer to the main data centre in Melbourne serving as a template for future experiments.
This poster will present details of the computing systems for SABRE South and how they will be used to support the experimental data taking and analysis.

Speaker: Jade McKenzie

Computing-and-Data-Management_SABRE_Jade-McKenzie_Lepton-Photon-2023_P42.pdf

Relevant Links

18:20 A novel method to measure the relative strong phase between $D^0$ and $\bar{D}^0$ in the $K_S^0 \pi^+ \pi^-$ decay mode from correlated $\psi(3770) \to D^0 \bar{D}^0$ decays, and an application to measuring the CKM angle $\gamma$ in $B^\pm \to D(\to K_S^0 \pi^+ \pi^-) K^\pm$ decays.

We present a novel method that measures the relative strong phase, $\Delta \delta_D$, between $D^0$ and $\bar{D}^0$ amplitudes decaying to the $K_S^0 \pi^+ \pi^-$ final state measured from correlated $D\bar{D}$ pairs produced at the charm threshold, and its application to the measurement of $CP$ violating observables in $B^\pm \to DK^\pm$ decays which includes the measurement of the CKM angle, $\gamma$, from $B^\pm \to D(\to K_S^0 \pi^+ \pi^-) K^\pm$ decays.
We test this method using simulated correlated $\psi(3770) \to D^0\bar{D}^0$ decays with at least one $D$ decaying to the $K_S^0 \pi^+ \pi^-$ final state and simulated $B^\pm \to D(\to K_S^0 \pi^+ \pi^-)K^\pm$ decays, we perform simultaneous fits to the correcting polynomial to $\Delta \delta_D$ and the CKM parameters, $x_\pm = r_B \cos\left(\delta_B \pm \gamma\right), y_\pm = r_B \sin\left(\delta_B \pm \gamma\right)$.
This method has better statistical precision than the binned measurement of $\gamma$ using the binned measurements of $\Delta \delta_D$ from charm threshold data. We test the ability of our method against mis-modelling $\Delta \delta_D$ by performing pull studies with a predetermined bias applied to $\Delta \delta_D$, we show that our method is able to recover the original $\Delta \delta_D$ and avoid biasing the CKM parameters $x_\pm, y_\pm$ in contrast to the unbinned model dependent measurement.

Speaker: Jake Lane (Monash University (AU))

A novel unbinned model-independent method to measure the CKM angle gamma in B+- --> DK+- decays with optimised precision

JL_LeptonPhotonQMIPoster_resized.pdf

18:22 Beyond the leading dipole approximation: modelling junctions in the event generator PYTHIA

The recent discovery at the LHC of order-of-magnitude enhancements of the $\Lambda_c/D$ ratio (relative to its LEP value) at low pT, and several related measurements, has prompted renewed interest in baryon production in hadron collisions, especially in the heavy-flavour sector. One scenario that successfully accounts for (and in fact predicted) these effects is based on QCD colour reconnections with so-called string junctions, already implemented in the event generator PYTHIA. String junctions are an explicitly beyond the leading colour string configuration that makes use of the SU(3) colour structure of QCD, and are particularly important as they provide a baryon production mechanism additional to standard string fragmentation. These junction baryons form around the junction itself, and thus the modelling of the junction motion is important for accurately predicting the effects of junctions on baryon production. Though junction topologies are already included in the event generator PYTHIA, the current modelling of junctions encounters convergence errors for around 10% of cases whilst using an unphysical averaging procedure, and neglects special treatment of so-called soft-quark cases. In order for a junction baryon to be a heavy-flavour baryon, the heavy quark is often considered soft, and thus these soft-quark cases become particularly important and the heavy-quark baryon becomes even more sensitive to the modelling of the junction motion. Though the predictions with the current modelling show a surprising agreement to data (particularly in the heavy-flavour sector), in order to draw conclusions about the impact of junction topologies, more physically robust modelling is required. Thus here we propose a new iterative procedure for modelling the junction motion, including a novel pearl-on-a-string treatment which takes care of junctions with a soft quark, aiming to more accurately describe and model heavy-flavour baryon production.

Speaker: Javira Altmann

Altmann_Lepton-photon.pdf

18:24 Flavour tagging with the ATLAS detector at the HL-LHC

The High-Luminosity LHC (HL-LHC) era will herald significant increases in both the instantaneous luminosity and the number of interactions per bunch crossing. To cope with these significantly more complex conditions, detector upgrades are planned to maintain and surpass the current physics performance. The replacement of the current Inner Detector with a new all-silicon Inner Tracker (ITk) is one of the key upgrades planned for the ATLAS detector. The ITk upgrade provides excellent tracking performance, which will enhance other reconstruction algorithms dependent upon tracking, and ultimately the physics reach of the experiment. In particular, the identification of jets originating from heavy flavour hadrons, known as flavour tagging, is heavily reliant upon tracking and is ideally placed to benefit from the detector upgrade. The performance of recent stateof-the-art flavour tagging algorithms applied to the upgraded ATLAS detector was previously presented, which achieved significant performance enhancements to the benefit of several physics analyses. However, new algorithmic developments could further benefit from the HL-LHC detector upgrades to provide additional enhancements in the performance. This talk will survey recent algorithmic developments in the ATLAS flavour tagging community, including algorithms based on deep sets and graph neural networks, and compare their performance with the previous algorithms in the context of HL-LHC upgrades such as the ITk.

Speaker: Valentina Cairo (CERN)

ATLAS_FTag_SRettie.pdf

18:25 Recent results on associated top quark production and searches for new top-quark phenomena with the ATLAS detector

The high center-of-mass energy of proton-proton collisions and the large available datasets at the CERN Large Hadron Collider allow to study rare processes of the Standard Model (SM) with unprecedented precision and search for new physics that might enhance extremely rare processes in the SM. Measurements of rare SM processes provide new tests of the SM predictions with the potential to unveil discrepancies with the SM predictions or provide important input for the improvement of theoretical calculations. Interesting processes are Flavour Changing Neutral Currents (FCNC): forbidden at tree level and highly suppressed at higher orders in the Standard Model (SM), FCNC processes can receive enhanced contributions in many extensions of the SM, so any measurable sign of such interactions is an indication of new physics. In this talk, total and differential measurements of top-quark production in association with additional bosons are shown using data taken with the ATLAS experiment at a center-of-mass-energy of 13 TeV. The recent observation of associated production of a single top quark with a photon completes the list of processes and adds sensitivity to the EW couplings of the top quark, while measurements of production asymmetries in various final states provide further precision tests of the SM. In addition, new searches for charged lepton flavour violation and FCNCs with the ATLAS experiment are shown, using the full data taken during Run-2 of the LHC, as well as other searches for beyond-the-Standard-Model phenomena in top-quark final states.

Speaker: Harish Potti (University of Adelaide (AU))

Harish_Lepton_Photon_2023.pdf

18:26 Alignment of the CMS tracker during Run 3 data taking

The high granularity tracker of CMS is the largest silicon tracker ever built with 1856 pixel and 15148 strip detector modules that provide accurate track reconstruction. To achieve high precision in measurements of the momenta of charged particles, corrections for the position, rotation and curvature of these modules must be found; such a procedure is known as tracker alignment. Magnet cycles, temperature variations and ageing of modules cause significant time variations that affect the track reconstruction and therefore necessitate continuous alignment throughout the operation of the LHC machine. Special challenges must be addressed in the Run 3 data-taking period as the high instantaneous luminosity and the newly installed layer 1 of the barrel pixel lead to fast changes in the irradiation of modules.

In this presentation, the performance of tracker alignment on Run 3 data will be presented, highlighting new features developed for the Run 3 data taking period. The impact of the tracker alignment on physics performance will also be reviewed.

Speaker: Alessandro Rossi (Universita e INFN, Perugia (IT))

poster_TkAl2023_finalPrint.pdf

18:27 TORCH, a novel time of flight detector for LHCb upgrade II

The Time Of internally Reflected CHerenkov detector (TORCH) is a proposed large-area time-of-flight detector, designed to enhance the particle identification performance of the Upgrade-II LHCb experiment in the 2–15 GeV/c momentum range. A TORCH module consists of a 10 mm thick quartz plate of dimensions 2.5 x 0.66 m$^2$ from which the positions and arrival times of Cherenkov photons from a charged track are detected by highly segmented MCP-PMTs. Each MCP-PMT has an active area of 53 x 53 mm$^2$ and a granularity of 64 x 8 pixels, and developed in collaboration with an industrial partner (Photek). A general overview of TORCH and its operating principles will be reviewed along with recent results from a half-length 1.25 m TORCH prototype module tested at the CERN proton synchrotron. In the most recent beam test in November 2022, the prototype module was instrumented with 6 MCP-PMTs compared to 2 MCP-PMTs in previous tests. The current status of the analysis of the latest data will be presented.

Speaker: Tom Hadavizadeh (Monash University (AU))

TORCH_leptonPhoton2023_2.pdf

18:28 Prometheus: An Open-Source Neutrino Telescope Simulation

The construction of a worldwide network of gigaton-scale neutrino telescopes aims to address multiple open questions in physics, such as the origin of astrophysical neutrinos and the acceleration mechanism of high-energy cosmic rays. Besides astrophysics, neutrino telescopes probe center-of-mass energies similar to colliders, offering an additional window into high-energy particle interactions.
Currently, there are no publicly available simulation tools for these detectors, leading to duplication in effort for each experiment and hindering the testing of theoretical models.
While these detectors are built in ice or water at different locations, they operate on the same detection principle: Using multiple optical modules to detect Cherenkov photons emitted by charged particles.
Using this, we developed Prometheus, an open-source simulation tool that offers a common simulation chain for all neutrino telescopes. It can inject neutrinos, propagate their interaction products, and model the amount of light reaching the optical modules of a user-defined detector in either ice or water. We will show its runtime performance, highlight successes in reproducing simulation results from multiple ice- and water-based observatories, and discuss simulation sets that we have made publicly available for various detectors.

Speaker: Stephan Meighen-Berger

Prometheus_SMB_LP.pdf

18:29 Trigger and data acquisition systems for SABRE South

The SABRE (Sodium-iodide with Active Background REjection) South experiment, located at the Stawell Underground Physics Laboratory (SUPL) in Australia, aims to measure an annual modulation in dark-matter interactions using ultra-high-purity NaI(Tl) crystals. In partnership with the SABRE North effort at the Gran Sasso National Laboratory (LNGS), SABRE South is designed to disentangle any seasonal or site-related effects from the dark matter-like modulated signal observed by DAMA/LIBRA in the Northern Hemisphere.
SABRE South is instrumented with 7 ultra-high-purity NaI(Tl) crystals surrounded by a liquid scintillator veto, and covered by 8 plastic scintillator muon detectors. Each NaI(Tl) crystal and muon detector is coupled to 2 photomultiplier tubes (PMTs) and a further 18 PMTs are used to detect interactions in the liquid scintillator giving a combined total of 48 channels. The data acquisition system for SABRE South utilises a number of CAEN digitisers to acquire waveform data for each of these PMTs. The trigger system is built upon a CAEN logic unit using custom FPGA logic which is extensively simulated and also tested in hardware to ensure long term reliability.
In this poster, the design and status of the SABRE South trigger and data acquisition systems will be shown.

Speaker: Lachlan McKie (Australian National University)

18:30 Simulation of the muon background at SUPL for the SABRE South Experiment

The low cross section of WIMP-nucleus scattering makes detecting dark matter directly extremely difficult. To make sure a signal originates from WIMP scattering, all the backgrounds of a dark matter experiment need to be carefully studied and reduced. Among all these backgrounds, muons can mimic the annual modulation signals expected from dark matter. Therefore, the distribution of muons should be understood.

SABRE (Sodium-iodide with Active Background REjection) aims to directly detect the annual modulation signals of nuclear recoils which are claimed to be caused by dark matter as reported by DAMA/LIBRA. SABRE South will operate an array of ultra-low background Na(Tl) scintillation detectors with muon and liquid scintillator systems to both measure and reject backgrounds at SUPL (Stawell Under-ground Physics Laboratory, Australia), the first underground laboratory in the Southern Hemisphere. The 1025m-thick rock overburden can greatly suppress the muon-related backgrounds. Construction of SUPL has recently been completed and a muon telescope consisting of eight plastic detectors will be operated to measure the underground muon angular distribution.

Details of Muon detector simulations for SABRE South and an underground muon background simulation with CRY (Cosmic-ray Shower Library) and also Geant4 will be shown. In the simulation, muons are generated at sea level with CRY and incident on rocks with a thickness of 1025 m. The results of muon flux, energy distribution and angular distribution underground will be shown, and compared with the results from other underground laboratories.

Speaker: Guangyong Fu (The University of Melbourne)

18:31 ATLAS ITk Pixel Detector Overview

In the high-luminosity era of the Large Hadron Collider, the instantaneous luminosity is expected to reach unprecedented values, resulting in up to 200 proton-proton interactions in a typical bunch crossing. To cope with the resulting increase in occupancy, bandwidth and radiation damage, the ATLAS Inner Detector will be replaced by an all-silicon system, the Inner Tracker (ITk). The innermost part of the ITk will consist of a pixel detector, with an active area of about 13 m2. To deal with the changing requirements in terms of radiation hardness, power dissipation and production yield, several silicon sensor technologies will be employed in the five barrel and endcap layers. Prototype modules assembled with RD53A readout chips have been built to evaluate their production rate. Irradiation campaigns were done to evaluate their thermal and electrical performance before and after irradiation. A new powering scheme – serial – will be employed in the ITk pixel detector, helping to reduce the material budget of the detector as well as power dissipation. This contribution presents the status of the ITk-pixel project focusing on the lessons learned and the biggest challenges towards production, from mechanics structures to sensors, and it will summarize the latest results on closest-to-real demonstrators built using module, electric and cooling services prototypes.

Speaker: Yu Nakahama Higuchi (High Energy Accelerator Research Organization (JP))

LP2023Poster_ATLASITk.pdf

18:32 Results from muon reconstruction performance with ATLAS at Run-3

Muon reconstruction performance plays a crucial role in the precision and sensitivity of the Large Hadron Collider (LHC) data analysis of the ATLAS experiment. Using di-muon Resonances we are able to calibrate to per-mil accuracy the detector response for muons. Innovative techniques developed throughout the Run-2 period and during the LHC shut-down significantly improve the measurement of muon reconstruction, identification and calibration performance with these preliminary data. New analysis techniques are exploited which involve multivariate analyses for rejecting background hadrons from prompt leptons from the hard interactions as well as innovative in-situ corrections on data that reduce biases in muon momenta induced from residual detector displacements. We measure the reconstruction efficiencies and momentum performance measured with these methods. The results achieved are fundamental for improving the reach of measurements and searches involving leptons, such as Higgs decays to dimuons and ZZ or the first low mass and high mass searches in the beyond-the-standard model sector. This talk will present the recently released results on the muon reconstruction performance using the Run-3 data collected in 2022 by the ATLAS detector.

Speaker: Andres Pinto (Johannes Gutenberg Universitaet Mainz (DE))

Melbourne_MCP_poster.pdf

18:33 The MDT Trigger Processor upgrade for ATLAS Muons at the HL-LHC

The Monitored Drift Tube (MDT) chambers Trigger Processor (MDT-TP) is a key component in the upgrade of the first-level muon trigger for ATLAS at the High-Luminosity LHC (HL-LHC). The selectivity of the current system is limited by the moderate spatial resolution of the trigger chambers: Resistive Plate Chambers (RPC) and Thin Gap Chambers (TGC). The MDT-TP incorporates the high-resolution MDT measurements to significantly improve the transverse momentum resolution of muon trigger candidates and to reduce the extra rate from mis-measured muons or accidental coincidences.
The MDT-TP is designed to have a fixed latency of 1.7 microseconds in response to the incoming muon trigger candidate.
The MDT-TP also provides the means to read out the MDT chambers. In addition to the trigger and readout, the MDT-TP is responsible for configuring the MDT front-end electronics.

The MDT-TP is expected to reduce the muon trigger rate by up to 70% while keeping a high-efficiency plateau of 95% for a single muon trigger with a transverse momentum threshold of 20 GeV.

This poster will describe the MDT-TP algorithms and their functionality, as well as progress with the hardware developments. First results from complete system tests will also be presented.

Speaker: Guillermo Loustau De Linares (University of Massachusetts (US))

L0MDT_LP2023_poster_GLdL_v0.6.pdf

Tuesday 18 July

09:00 → 10:30 BSM

Convener: Prof. Ben Allanach (University of Cambridge (GB))

09:00 SMEFT status from a theoretical perspective

Speaker: Rick Gupta

OOM_Melbourne.pdf

09:30 Direct searches for BSM resonances

Speaker: Mingshui Chen (Chinese Academy of Sciences (CN))

202307-LP-chenms-v5.pdf

10:00 NP searches in an EFT context

This talk will present an experimental overview of searches for New Physics performed through the interpretation of several results in Effective Field Theory frameworks. The emphasis will be on the most recent publications by the ATLAS and CMS collaborations, including Standard Model, Top, single Higgs and double Higgs analyses.

Speaker: Valentina Cairo (CERN)

LP2023_VMMCAIRO_18July2023.pdf

10:30 → 11:00 Morning break

11:00 → 11:30 BSM

Convener: Prof. Ben Allanach (University of Cambridge (GB))

11:00 New Physics Opportunities at HL-LHC and Beyond

Speaker: Zhen Liu (University of Minnesota (US))

BSMTheory_LeptonPhoton2023_ZL_split.pdf

11:30 → 12:30 Neutrino

Convener: Paul Soler Jermyn (University of Glasgow (GB))

11:30 Theory challenges in neutrino physics

Speaker: Stephen Parke (Fermi National Accelerator Lab. (US))

parke_LP2023.pdf

12:00 Future long baseline experiments

Speaker: Francesco Terranova (Universita & INFN, Milano-Bicocca (IT))

terranova_leptonphoton_jul2023_16_9.pdf

12:30 → 13:30 Lunch

13:30 → 15:15 Astrophysics: Room C

13:30 Dark Matter production from two evaporating PBH Distributions

Particulate Dark Matter (DM), completely isolated from the Standard Model particle sector, can be produced in the early universe from Primordial Black Hole (PBH) evaporation. However, Big Bang Nucleosynthesis (BBN) observations put an upper bound on the initial mass of PBH requiring the PBH to evaporate completely before the advent of BBN. DM particles in the mass range ∼(1-10^9) GeV can not explain the observed relic abundance for an early matter dominated universe due to this BBN constraint. However, this assumes the presence of only one monochromatic PBH mass distribution in the early universe. In this work, we explore the simple possibility of achieving the observed relic with DM masses from the above mentioned range for an early matter dominated era with two monochromatic evaporating PBH mass distributions and demonstrate that the BBN constraints can be alleviated to a good degree.

Speaker: Arnab Chaudhuri (Indian Institute of Technology, Gandhinagar)

13:45 Dark Matter Capture in Compact Objects

The capture of Dark Matter in compact objects has garnered considerable interest over recent years. This renewed interest is driven primarily by the prospect that the energy deposited by the dark matter can heat these objects potentially to infra-red temperatures, which may soon be observed. Such observations can constrain dark matter interactions complementary to modern direct detection experiments. To gain reliable insight into the reach these objects can offer, correctly incorporating the unique physics relevant to these objects into the capture process is necessary. Key among these are the effects of gravitational focusing, relativistic kinematics for targets and dark matter, Pauli blocking due to degenerate targets, and multiple scattering effects. Additionally, we incorporate the internal structure of the objects in a self consistent manner. Specifically for Neutron stars, baryonic targets have additional physics which needs to be accounted for. These are the effects of strong interactions which induce an effective mass, and accounting for their finite size. We can then project realistic sensitivities for dark matter-lepton and nucleon cross sections using dimension-6 effective operators, which are competitive and potentially stronger than those obtained from direct detection searches.

Speaker: Michael Virgato

Lepton Photon 2023 MV.pdf

14:00 Advancing Globular Cluster Constraints on the Axion-Photon Coupling

For decades stellar evolution has been a rich source of constraints on physics beyond the Standard Model. In this talk I will discuss our recent improvement of the upper bound on the axion-photon coupling from stellar evolution, which has been derived using the $R_2$ parameter, the ratio of stellar populations on the Asymptotic Giant Branch to Horizontal Branch in Globular Clusters. I will compare observed limits on $R_2$ with data from simulations using the stellar evolution code MESA which include the effects of axion production. The benefits of considering $R_2$ over the traditionally employed $R$-parameter will be discussed, with particular attention given to quantifying in detail the effects of uncertainties on these parameters due to the modelling of convective core boundaries. Using a semiconvective mixing scheme we constrain the axion-photon coupling to be $g_{a\gamma\gamma}<0.47\times 10^{-10}$ GeV$^{-1}$. This rules out new regions of QCD axion and axion-like particle parameter space. Complementary evidence from asteroseismology suggests that this could improve to as much as $g_{a\gamma\gamma}<0.34\times 10^{-10}$ GeV$^{-1}$ as the uncertainties surrounding mixing across convective boundaries are better understood.

Speaker: Frederick Hiskens (The University of Melbourne)

Lepton_Photon_2023_FJH.pdf

14:15 Capture of Dark Matter in Neutron Stars and White Dwarfs

Dark Matter candidates with cross sections as tiny as $10^{-45}cm^2$ can be captured efficiently in compact stars, like Neutron Stars and White Dwarfs.

The collisions to capture Dark Matter would heat the star, raising its equilibrium temperature, around 2000K for a NS. Thus, observation of old and cold NS that should have reached equilibrium can be used to set constraints on the capture cross section.

In this talk, we present the formalism to calculate capture rates in NS and WD in the optically thin and optically thick regimes, and the limits on the DM-nucleuo cross section that one could infer from non-observation.

Speaker: Giorgio Busoni (The Australian National University)

Lepton_photon_2023 (1).pdf

14:30 Constraining Phase Transitions in Grand Unified Theories with Gravitational Waves

The era of gravitational wave (GW) astronomy offers a new avenue to explore the early universe and with it an energy scale that may never be accessible to terrestrial colliders. This provides a fresh new way to investigate the phenomenology of grand unified theories (GUT). We construct an $SO(10)$ inspired Pati-Salam model encompassing an intermediate minimal left-right symmetric model. We calculate the stochastic GW background associated with the $SU(4)$ symmetry breaking phase transition and find that, in general, the spectrum peaks well above the sensitivity windows of any current or proposed GW detector. However, for some regions of the parameter space, the signal peaks close to LIGO and VIRGO's most sensitive region. We assess to what extent the LIGO-VIRGO network can already be used as a way to constrain GUT models and to what extent future observatories such as the Einstein Telescope could improve on this.

Speaker: Matthew Pearce (Monash University)

GUT_PTs_MatthewPearce.pdf

13:30 → 15:15 Diversity, Inclusion, Equity and Outreach: Room E

Convener: Dr Irene Bolognino (The University of Adelaide)

13:30 LA-CoNGA physics: an open science education collaboration between Latin America and Europe for High Energy Physics

The communities of astrophysics, astronomers and high energy physicists have been pioneers in establishing Virtual Research and Learning Networks (VRLCs)[1] generating international productive consortiums in virtual research environments and forming the new generation of scientists. These environments are key to improve accessibility and inclusion for students and researchers in developing countries. In this talk we will discuss one in particular: LA-CoNGA Physics (Latin American alliance for Capacity buildiNG in Advance physics) [2].

LA-CoNGA physics aims to support the modernization of the university infrastructure and the pedagogical offer in advanced physics in four Latin American countries: Colombia, Ecuador, Peru and Venezuela. This virtual teaching and research network is composed of 3 partner universities in Europe and 8 in Latin America, high-level scientific partners (CEA, CERN, CNRS, DESY, ICTP), and several academic and industrial partners. The project is co-funded by the Education, Audiovisual and Culture Executive Agency (EACEA) of the European Commission.

Open Science education and Open Data are at the heart of our operations. In practice LA-CoNGA physics has created a set of postgraduate courses in Advanced Physics (high energy physics and complex systems) that are common and inter-institutional, supported by the installation of interconnected instrumentation laboratories and an open e-learning platform. This program is inserted as a specialization in the Physics masters of the 8 Latinamerican partners in Colombia, Ecuador, Peru and Venezuela. It is based on three pillars: courses in high energy physics theory/phenomenology, data science and instrumentation. The program is complemented by transversal activities like seminars, citizen science projects and open science hackathons [3].

In the current context, VRLCs and e-learning platforms are contributing to solve challenges, such as distance education during the COVID19 pandemic and internationalization of institutions in developing countries.

[1] http://www.oecd.org/sti/inno/international-distributed-research-infrastructures.pdf
[2] http://laconga.redclara.net
[3] https://laconga.redclara.net/hackathon/

Speaker: Reina Coromoto Camacho Toro (LPNHE-Paris CNRS/IN2P3)

202307_LP2023_LA-CoNGA_Camacho.pdf

13:45 Engaging the Classroom – ATLAS Visits, Virtual Visits, Masterclasses, Cheat Sheets and More

The ATLAS Collaboration provides a range of outreach and engagement opportunities appropriate for classroom engagement with particle physics developed by the ATLAS Collaboration. Here we present details of the exhibits/features and use of the new ATLAS Visitors Centre at CERN – the most visited external visitor site at CERN – as well as an overview of the highly-successful Virtual Visit programme bringing CERN and the ATLAS experiment to tens of thousands of people. We also present an overview of ATLAS contributions to international Masterclasses and showcase resources such as ‘Cheat Sheets’ and ‘Fact Sheets’, which are intended to cover key topics of the work done by the ATLAS Collaboration and the physics behind the experiment for a broad audience of all ages and levels of experience. This contribution will also present some of the efforts to make visits and available resources more inclusive and accessible to a wider and more diverse audience.

Speaker: Ms Joni Pham (University of Melbourne (AU))

EngagingClassroom_LeptonPhoton2023_MelbourneTalk.pdf

14:00 Particle Physics Masterclasses for the Public: Finding the Scientist in Everyone

The International Particle Physics Outreach Group (IPPOG) is a network of scientists, science educators and communication specialists working across the globe in informal science education and public engagement. Its flagship educational program, International Particle Physics Masterclasses, reaches thousands of students each year around the world, turning them into scientists for a day. The participants meet scientists from local institutes and laboratories, learn about current research, then try their hand at analysing real data from particle physics experiments.
Recently, IPPOG members have explored bringing this masterclass formula outside of the classroom to the public. Masterclasses have been held at music festivals, for business management training, and for non-scientific personnel working at the CERN laboratory. These attempts have been very popular and highly successful. Participants have learned valuable lessons on scientific methodology, the goals of current research, and have gained an appreciation for the relevance of the field for society. We present the results of these pilot efforts and discuss plans for the future.

Speaker: Jacqueline Bondell (University of Melbourne)

IPPOG for Lepton Photon.pdf

IPPOG for Lepton Photon.pptx

14:15 Engaging the Public through social media and the web

Communicating the science and achievements of the ATLAS Experiment is a core objective of the ATLAS Collaboration. How do we most effectively engage and educate the public through social media and web content? This contribution will explore the range of communication strategies adopted in ATLAS communications, and lessons learned. In particular, an overview of ATLAS’ digital communication platforms will be given – with focus on social media, web content, YouTube, and Virtual Visits – and the effect on target audiences evaluated with best practices are shared.

Speaker: Reina Coromoto Camacho Toro (LPNHE-Paris CNRS/IN2P3)

202307_LeptonPhoton_CamachoToro-v2.pdf

14:30 Empowering Diversity: Promoting LGBTQ+ Inclusivity in High Energy Physics

Diversity plays a crucial role in advancing scientific research. Building a successful career in physics involves not only conducting research, but also collaborating with colleagues, attending conferences, and networking. However, members of the LGBTQ community often face additional challenges and barriers that can hinder their progress in the field.

The LGBTQ+ CERN group is a CERN-recognised Informal Network seeking to provide a welcoming space for lesbian, gay, bisexual, trans*, intersex, asexual, genderqueer and other LGBTQ+ individuals at CERN, also welcoming friends and allies.

This talk will delve into the experiences of LGBTQ CERN members in their careers in high energy physics and explore the group's efforts to reach out to both the LGBTQ community and the broader CERN community. Additionally, the talk will highlight specific actions that can be taken to create a supportive and inclusive work environment for all members of the scientific community.

Speaker: Emily Filmer (University of Adelaide (AU))

EFilmer_LP2023_LGBTQIACERN.pdf

14:45 An Update on Demographics and Diversity and Inclusion Efforts with the Belle II Collaboration

The Belle II Collaboration comprises over 1000 international high
energy physicists, who investigate the properties of $b$-quarks and
other particles at the luminosity frontier. In order to achieve our
aim of a successful physics program, it is essential that we
emphasise contributions from a diverse community. Belle II has thus
far focused on diversity in gender and sexuality, among other efforts
within our collaboration. These efforts are led by our two Diversity
Officers, elected to the newly created positions in 2018. Their role has been to promote an inclusive atmosphere, raising awareness of diversity and being a safe first point of call for issues of discrimination and harassment.
This talk will describe the details the efforts described above, as
well as examining the evolving demographics of our community, since membership began in 2011.

Speaker: Shanette De La Motte

Diversity and inclusion activities at the Belle II LP2023.pdf

Diversity and inclusion activities at the Belle II LP2023.pptx

15:00 Gender Equity in High Energy Physics in India: Status and Initiatives

Gender Equity in High Energy Physics in India: Status and Initiatives

The scientific community in India, as their counterparts elsewhere, is still struggling to achieve gender parity in STEM fields, particularly in physics. This is not a desirable situation since an equitable contribution from all genders can only enrich any enterprise. In contrast to the inherent objectivity in science, existing practices in scientific endeavour are rooted in age old biases and discriminations. Statistics reveal that while at the undergraduate, postgraduate and PhD levels, there are large fractions of women in physics (close to 50%), the situation rapidly worsens as one goes higher up, and the fraction of female faculty nosedives to about 13% demonstrating a very "leaky pipeline syndrome".When it comes to recognition in terms of awards and leadership positions, the number becomes minuscule, demonstrating the well known, but largely unrecognised "glass ceiling effect". The Gender in Physics Working Group (GIPWG) was formed in India in 2017 under the Indian Physics Association. This group is spearheading activities so that a career in physics in India is more gender inclusive. In particular, initiatives have been taken to form gender groups in different branches of physics to address subject-specific issues obstructing gender parity. For example, a gender group for High Energy Physics was established in 2020. This group is now active in raising awareness in the community by identifying underlying issues and suggesting possible interventions towards affirmative action. In particular, this group organised the first-ever Gender session and a panel discussion on "Gender Imbalance in String Theory: Focus on India" at the Indian String meet 2021. Gender sessions at the National DAE-BRNS Symposium on High Energy Physics have now been regularised. During the 2022 meeting, a panel discussion on "Two Body Problem in Academia and Possible Ways to Overcome it" was organised. Due to the coordinated efforts of the GIPWG, the International Conference of Women in Physics will be held in India in July 2023 in online mode. This will be a unique opportunity that will boost similar initiatives. There are other initiatives including those by the government of India to counter gender imbalance by implementing inclusive policies. This talk will present gender statistics in High Energy Physics in India, the various proactive measures adopted to ameliorate the under-representation of women in physics in India. We hope some of these can serve as illustrative examples to tackle these issues globally.

Speaker: Dr MoonMoon Devi (Tezpur University)

LP23_genderHEP.pdf

13:30 → 15:15 Flavour: Clarendon Auditorium

Convener: Yuehong Xie (Central China Normal University CCNU (CN))

13:30 Latest results and precision measurements from the NA62 experiment

The NA62 experiment at CERN collected the world’s largest dataset of charged kaon decays in 2016-2018, leading to the first measurement of the branching ratio of the ultra-rare $K^+ \rightarrow \pi^+ \nu \bar\nu$ decay, based on 20 candidates, and presented in 2021.
In this talk the NA62 experiment reports new results from analyses of $K^+ \rightarrow \pi^+ \mu^+ \mu^-$ and $K^+\rightarrow \pi^+ \gamma \gamma$ decays, using a data sample recorded in 2017--2018. The $K^+ \rightarrow \pi^+ \mu^+ \mu^-$ sample comprises about 27k signal events with negligible background contamination, and the presented analysis results include the most precise determination of the branching ratio and the form factor. The $K^+ \rightarrow \pi^+ \gamma \gamma$ sample contains about 4k signal events with $10\%$ background contamination, and the analysis improves the precision of the branching ratio measurement by a factor of 3 with respect to the previous measurements.
The NA62 experiment can also be run as a "beam-dump experiment" by removing the Kaon production target and moving the upstream collimators into a "closed" position. More than $10^{17}$ protons on target have been collected in this way during a week-long data-taking campaign by the NA62 experiment. We report on new results from analysis of this data, with a particular emphasis on Dark Photon and Axion-like particle Models.

Speaker: Francesco Brizioli (CERN)

LP2023Melbourne_NA62_Brizioli.pdf

13:45 Lepton-flavour-violating constraints from triality

Lepton flavour triality is motivated by flavour symmetry models. Reference ([ https://doi.org/10.1103/PhysRevD.107.055001]) constructed theories based on a low-energy limit featuring lepton flavour triality that has flavour-violating tau decays as the main phenomenological signatures of physics beyond the standard model. These theories have doubly charged scalars as mediators. In this work, we derive further constraints on the triality model considering future colliders' predictions.

Speaker: Gabriela Lichtenstein (UNSW)

LichtensteinLepotonPhoton.pdf

14:00 Charm physics as BESIII

BESIII has taken 2.93, 7.33, and 4.5 $fb^{-1}$ of $e^+e^-$ collision data at energies of 3.773, 4.128-4.226, and 4.6-4.7 GeV, collecting the world largest dataset of of $D\bar{D}$, $D_sD_s$, and $\Lambda_c^+\Lambda_c^-$ pairs. On the subject of charmed meson, we will report the updated measurements of $|V_{cs}|$ in $D_s^+ \to \tau^+ \nu$ and the form factor studies in $D_s^+ \to K^+K^- e^+ \nu$ and $\pi^+\pi^- e^+ \nu$. In addition, we will report the amplitude analyses of Cabibbo-favored and -suppressed $D_s$ decays, including the observation of a new $a^0$-like state at 1.817 GeV, the branching fraction measurements of D mesons decay involving $K_L^0$, and the doubly Cabibbo-suppressed decay $D^0 \to K^+\pi^-\pi^0$. We will also report the improved measurement of the strong-phase difference in quantum-correlated DD decays. On the subject of charmed baryon, we will report the form factor measurement in $\Lambda_c^+ \to \Lambda e^+ \nu$, the observation of $\Lambda_c^+ \to p K^-e^+\nu$, and an improved measurement of $\Lambda_c^+ \to Xe^+\nu$. Moreover, we will report the amplitude analysis of $\Lambda_c^+ \to \Lambda \pi^+ \pi^0$ and the observations of Cabibbo-suppressed $\Lambda_c^+$ decays. Finally, we will present the prospect on measurements of charmed meson hadronic decays with the coming 20 $fb^{-1}$ of data data collected at 3.773 GeV by BESIII.

Speaker: Xu-Dong Yu

20230718_yuxd_Charm_LP_v3.pdf

14:15 Mixing and CPV in charm decays at LHCb

LHCb has collected the world's largest sample of charmed hadrons. This sample is used to measure $D^0 -\overline{D}^0$ mixing and to search for $C\!P$ violation. New measurements from several decay modes are presented, as well as prospects for future sensitivities.

Speaker: Tom Hadavizadeh (Monash University (AU))

Hadavizadeh_CharmCPV_v3.pdf

14:30 Rare decays of charm hadrons at LHCb

LHCb is playing a crucial role in the study of rare and forbidden decays of charm hadrons, which might reveal effects beyond the Standard Model. We present the latest searches for, and measurements using, rare charm decay processes with two leptons in the final state.

Speaker: Alessandro Scarabotto (Centre National de la Recherche Scientifique (FR))

A_Scarabotto_LeptonPhoton_RareCharm_final.pdf

14:45 Recent Belle II results on time-dependent CP violation and charm physics

Time-dependent measurements of CP violation are chief goals of the Belle II physics program. Comparison between penguin-dominated $b \to q\bar qs$ and tree-dominated $b \to c \bar cs$ results allows for stringent tests of CKM unitarity that are sensitive to non-SM physics.
This program requires excellent vertexing capabilities. After presenting recent world-leading results on charm-hadron lifetimes that demonstrate the Belle II vertexing performance, we report on recent results on $B^0 \to K_S \pi^0$, $B^0 \to K_S K_S K_S$, and $B^0 \to \phi K_S$ decays. In addition, a novel algorithm to identify the flavor of neutral charm mesons is presented that effectively doubles the sample size for many measurements of CP violation and flavor mixing.

Speaker: Michele Veronesi

veronesi-lp23-v3.pdf

15:00 Recent Belle II results on semileptonic B decays and tests of lepton-flavor universality

Semileptonic $B$-meson decays allow for determining the magnitudes of the CKM matrix parameters $|V_{cb}|$ and $|V_{ub}|$, two fundamental parameters of the SM flavor sector and to probe the excess rate of semitauonic $B$ decays, which has been consistently above expectations in recent years. Belle II analyses use both exclusive decays such as $B \to D^*\ell \nu$ and $B \to \pi \ell \nu$, or inclusive $X_c \ell \nu$ or $X_u \ell \nu$ final states restricted in phase space. The low-background collision environment, along with the possibility of partially or fully reconstructing one of the two $B$ mesons in the event, offer precisions on $|V_{cb}|$ and $|V_{ub}|$ approaching that of world-best results and provides unique probes of lepton-flavor universality violation.

Speaker: Kazuki KOJIMA (Nagoya University)

2023-07-04_LP2023_KojimaFinalVer_main.pdf

13:30 → 15:15 Neutrino: Room D

Convener: Prof. Raymond Volkas (The University of Melbourne)

13:30 Performing a Bayesian Oscillation Analysis at T2K

T2K is a long-baseline off axis neutrino experiment producing world leading neutrino oscillation measurements using the neutrino beam produced at J-PARC. It consists of two key detectors: the near detector, ND280, located 280 meters downstream from the source, and the far detector, Super-Kamiokande, located 295 km away from the source. The near detector primarily constrains the properties of un-oscillated neutrinos, while the far detector measures the long-baseline neutrino oscillations. MaCh3 performs a Bayesian MCMC-based (Markov Chain Monte Carlo) analysis that simultaneously fits both the near and far detector data, extracting oscillation parameters and constraining systematic uncertainties. In this talk, I will present results from the oscillation analysis utilizing a new multi-ring muon-like selection at the far detector. Additionally, there will be a discussion of the official joint oscillation analyses with atmospheric neutrinos in Super-Kamiokande and the joint analysis with NOvA data.

Speaker: Henry T Israel

Performing a Bayesian Analysis at T2K.pdf

13:45 Atmospheric neutrino oscillations at JUNO

The Jiangmen Underground Neutrino Observatory (JUNO) is under construction, and represents a major breakthrough on the large-scale, high-precision liquid scintillator (LS) detector. Its primary physics goal is to determine the neutrino mass ordering (NMO), where the predominant sensitivity is from reactor neutrinos, while atmospheric neutrinos collected in JUNO can provide independent inputs. Recent investigations have revealed great potential for determining the directionalities, flavors, and energies of atmospheric neutrinos, which will lead to the enhancement of NMO sensitivity. This talk will report the progresses and status on various aspects of atmospheric oscillation research at JUNO, including atmospheric neutrino flux, neutrino interaction models in LS, discrimination between atmospheric neutrinos and backgrounds, sensitivity evaluation, etc.

Speakers: Wuming Luo, Wuming Luo (Institute of High Energy Physics, Chinese Academy of Science)

LP23_atmNu_luowm.pdf

14:00 Imprints of scalar mediated NSI on long baseline experiments

The experimental observation of the phenomena of neutrino oscillations, which essentially confirms non-zero masses of neutrinos, has opened a new sector to explore physics beyond the Standard Model (SM). The models describing new-physics phenomena often come with some unknown interactions of neutrinos termed as Non Standard Interactions (NSIs). It is highly important and interesting to explore the impact of NSIs in the ongoing and upcoming neutrino oscillations experiments for precise measurement of the oscillation parameters. In this work, we have probed the impact of a scalar-mediated NSI in the long baseline sector, focussing at the three upcoming long-baseline (LBL) experiments: (DUNE, T2HK and T2HKK). The effects of scalar NSI appear as a medium-dependent corrections to the neutrino mass term. Its contribution scales linearly with matter density, making LBL experiments among the most suitable candidates for probing such effects. We show that the presence of scalar NSI may significantly impact the oscillation probabilities as well as the event rates at the detectors and the $\chi^2$-sensitivities of $\delta_{CP}$ measurements of the experiments. We also show that, a synergy among the LBL experiments (DUNE+T2HK, DUNE+T2HKK), which may offer a better capability of constraining the scalar NSI parameters as well as an improved sensitivity towards CP-violation.

Speaker: Dr Moon Moon Devi (Tezpur University, India)

SNSI_lp23_devimm.pdf

14:15 DUNE trigger and data acquisition systems

The Deep Underground Neutrino Experiment (DUNE) is a next-generation long-baseline neutrino experiment currently under construction in the US. The experiment consists of a broadband neutrino beam from Fermilab to the Sanford Underground Research Facility (SURF) in Lead, South Dakota, a high-precision near detector, and a large liquid argon time-projection chamber (LArTPC) far detector. Two prototypes of the DUNE far detector (DUNE-FD) were constructed to assess candidate technologies and methods in advance of the DUNE detector build: Proto-DUNE single-phase horizontal-drift (ProtoDUNE-HD) and ProtoDUNE single-phase vertical-drift (ProtoDUNE-VD). Each prototype cryostat comprises two primary sub-detectors: a single-phase LArTPC and a companion photon detector system.
DUNE has a broad physics program that includes determining the neutrino mass hierarchy, measuring 𝛿𝐶 𝑃 with sufficient precision to discover leptonic CP violation, making precise measurements of the oscillation parameters governing electron neutrino appearance and muon neutrino disappearance, detecting neutrinos from a core-collapse supernova, searching for baryon number violating processes such as nucleon decay and neutron-antineutron oscillation, and searching for other physics beyond the Standard Model.
The Trigger and Data Acquisition (TDAQ) systems are responsible for the acquisition and selection of data produced by the DUNE detectors, as well as for their synchronization and recording. The main challenge for the DUNE-TDAQ lies in the development of effective, resilient software and firmware that optimize the performance of the underlying hardware. The TDAQ is composed of several hardware components. A high-performance Ethernet network interconnects all the elements and allows them to operate as a single, distributed system. At the output of the TDAQ the high-bandwidth Wide Area Network (WAN) allows the transfer of data.

Speaker: Danaisis Vargas Oliva (University of Toronto (CA))

slides(2023-07-18)LP_new.pdf

14:30 Vector leptoquark $U_3$: A possible solution to the recent discrepancy between NOvA and T2K results on CP violation

In the current epoch of neutrino physics, many experiments are aiming for precision measurements of oscillation parameters. Thus, various new physics scenarios which alter the neutrino oscillation probabilities in matter deserve careful investigation. Recent results from NOvA and T2K show a slight tension on their reported values of the CP violating phase $\delta_{CP}$. Since the baseline of NOvA is much larger than the T2K, the neutral current non-standard interactions (NSIs) of neutrinos with the earth matter during their propagation might play a crucial role for such discrepancy. In this context, we study the effect of vector leptoquark $U_3$, which induces non-standard neutrino interactions that modify the oscillation probabilities of neutrinos in matter. We show that such interactions provide a relatively large value of NSI parameter $\varepsilon_{e \mu}$. Considering this NSI parameter, we successfully explain the recent discrepancy between the observed $\delta_{CP}$ results of T2K and NOvA. We also briefly discuss the implication of $U_3$ leptoquark on lepton flavour violating muon decay modes: $\mu \to e \gamma$ and $\mu \to ee e$.

Speaker: Prof. Rukmani Mohanta (University of Hyderabad)

Lepton-Photon-RM.pdf

15:15 → 15:45 Afternoon break

15:45 → 17:30 BSM: Room C

Convener: Claudia Hagedorn

15:45 Recent results on VBS measurements at CMS

Vector boson scattering is a key production process to probe the electroweak symmetry breaking of the standard model, since it involves both self-couplings of vector bosons and coupling with the Higgs boson. If the Higgs mechanism is not the sole source of electroweak symmetry breaking, the scattering amplitude deviates from the standard model prediction at high scattering energy. Moreover, deviations may be detectable even if a new physics scale is higher than the reach of direct searches. This talk will present recent VBS measurements from CMS, which include constraints on anomalous quartic gauge couplings in the effective field theory framework.

Speaker: Li Yuan (Beihang University (CN))

VBS_LP2023_LiYuan.pdf

16:00 Searches for supersymmetric particles with prompt decays with with the ATLAS detector

Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. This talk will present the latest results from SUSY searches conducted by the ATLAS experiment. The searches target multiple final states and different assumptions about the decay mode of the produced SUSY particles, including searches for both R-parity conserving models and R-parity violating models and their possible connections with the recent observation of the favour and muon g-2 anomalies. The talk will also highlight the employment of novel analysis techniques, including advanced machine learning techniques and special object reconstruction, that are necessary for many of these analyses to extend the sensitivity reach to challenging regions of the phase space.

Speaker: John Kenneth Anders (CERN)

janders_LP2023.pdf

16:15 Search for new physics with long-lived and unconventional signatures in CMS

Many extensions of the standard model predict new particles with long lifetimes or other properties that give rise to non-conventional signatures in the detector. This talk discusses new techniques to detect such signatures in the CMS detector, and presents recent results from such searches in CMS using the full Run-II data-set of the LHC.

Speaker: Daniel Diaz (Univ. of California San Diego (US))

LeptonPhoton-LLP.pdf

16:30 Searching for new symmetries in the Higgs sector at ATLAS

The discovery of the Higgs boson with the mass of 125 GeV confirmed the mass generation mechanism via spontaneous electroweak symmetry breaking and completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many experimental measurements, it is not capable of solely explaining some observations. Many extensions of the Standard Model introduce additional scalar fields to account for the electroweak symmetry breaking and thereby extra Higgs-like bosons, which can be either neutral or charged. This talk presents recent searches for additional low- or high-mass Higgs bosons, as well as decays of the 125 GeV Higgs boson to new light scalar particles, using LHC collision data at 13 TeV collected by the ATLAS experiment in Run 2.

Speaker: Yanlin Liu (Shandong University (CN))

LP2023_Yanlin.pdf

16:45 Leptoquark searches at CMS

Leptoquarks could naturally explain the relation between the quark and lepton sectors in terms of both the ordering and electric charge, the latter a result of SM fermions and leptoquarks being composed of common elementary constituents, or motivated by grand unified theories, in which quarks and leptons appear in common multiplets relating their charges and giving rise to transitions mediated by leptoquarks. Leptoquarks coupling to third-generation particles would invoke processes that coherently yield a good description of excesses seen in heavy-flavor data, and are expected to be produced singly, in pairs, and exchanged in t-channel processes at the LHC. In this contribution, we will overview the CMS leptoquark program, with a particular focus on third-generation leptoquark searches.

Speaker: Ben Kilminster (University of Zurich (CH))

Leptoquarks-LP2023-Kilminster-final.pdf

17:00 Measurement of multiboson production at ATLAS

Measurements of diboson and triboson production at the LHC probe the electroweak gauge structure of the Standard Model for contributions from anomalous couplings. In this talk recent ATLAS results on the measurement W boson pairs are presented. The measurement improves in precision compared to previous measurements, and is compared to theoretical predictions from fixed order calculation and state-of-the-art event generators. In addition, the observation of rare triboson processes in the WW$\gamma$, WZ$\gamma$ and WW$\gamma$ channels and differential measurement of Z$\gamma \gamma$ production are highlighted.

Speaker: Walter Hopkins (Argonne National Laboratory (US))

Measurement of multiboson production at ATLAS.pdf

15:45 → 17:30 Dark Matter: Room E

15:45 Dark SHINE——A newly proposed fixed-target experiment at the SHINE facility in Shanghai

Referring to: Sci. China-Phys. Mech. Astron., 66(1): 211062 (2023), DOI: 10.1007/s11433-022-1983-8

Dark SHINE is a newly proposed fixed-target experiment at SHINE (Shanghai high repetition rate XFEL and extreme light facility, being the 1st hard X-ray FEL in China) under construction targeting completion in 2026. Dark SHINE aims to search for the new mediator, Dark Photon, bridging the Dark sector and the ordinary matter. In this work and presentation, we present the idea of this new project and 1st prospective study in search for Dark Photon decaying into light dark matter. It also provides the opportunity to incorporate broader scope of BSM search ideas utilizing the fixed-target experiment of this type.

Speaker: Shu Li (Tsung-Dao Lee Institute (CN) & Shanghai Jiao Tong Univ. (CN))

16:00 Recent dark-sector and tau physics results at Belle II

Belle has unique reach for a broad class of models that postulate the existence of dark matter particles with MeV—GeV masses. In addition, the low-background environment of electron-positron collisions and an hermetic detector make Belle II the premier experiment for studying tau-lepton physics. This talk presents recent world-leading results from Belle II searches for dark $Z’$ decays and long-lived (pseudo) scalars in $B$ decays. In addition, the world’s most precise determination of the tau lepton mass and searches for tau decays into a scalar non-SM particle and a lepton are reported.

Speaker: Savino Longo (University of Manitoba)

LeptonPhoton2023_VF.pdf

16:15 Recent Dark Matter related searches with the BABAR detector

We present the most recent $BABAR$ searches for reactions that could simultaneously explain the presence of dark matter and the matter-antimatter asymmetry in the universe. This scenario predicts $B$-meson decays into a ordinary-matter baryon and a dark-sector anti-baryon $\psi_D$ with branching fractions accessible at the $B$ factories.
The results are based on the full data set of about 430 $\text{fb}^{-1}$ collected at the $\Upsilon(4S)$ resonance by the $BABAR$ detector at the PEP-II collider.
We search, in particular, for decays like $B^{0}\to\psi_{D} {\cal B}$ where $\cal{B}$ is a baryon (proton, $\Lambda$, or $\Lambda_c$). The hadronic recoil method has been applied with one of the $B$ mesons from $\Upsilon(4S)$ decay fully reconstructed, while only one baryon is present in the signal $B$-meson side. The missing mass of signal $B$ meson is considered as the mass of the dark particle $\psi_{D}$. Stringent upper limits on the decay branching fraction are derived for $\psi_D$ masses between 1.0 and 4.2 GeV/c$^2$.

Speaker: Xinchou Lou (Chinese Academy of Sciences (CN))

LP2023-Mel-XCLOU-07182023.pdf

16:30 Dark matter and strong SUSY searches from CMS

Determination of the nature of dark matter is one of the most fundamental problems of particle physics and cosmology. This talk presents recent searches for dark matter particles from the CMS experiment at the Large Hadron Collider. The talk covers also covers recent searches for strong production of Supersymmetric (SUSY) particles with and some without the SUSY dark matter candidates. The results are obtained from the proton-proton collision data with luminosity up to 138 fb-1 at the center of mass energy of 13 TeV collected during the LHC Run 2.

Speaker: Varun Sharma (University of Wisconsin Madison (US))

lp2023-VS.pdf

16:45 Searches for Dark Matter with the ATLAS Experiment at the LHC

The presence of a non-baryonic Dark Matter (DM) component in the Universe is inferred from the observation of its gravitational interaction. If Dark Matter interacts weakly with the Standard Model (SM) it could be produced at the LHC. The ATLAS Collaboration has developed a broad search program for DM candidates in final states with large missing transverse momentum produced in association with other SM particles (light and heavy quarks, photons, Z and H bosons, as well as additional heavy scalar particles) and searches where the Higgs boson provides a portal to Dark Matter, leading to invisible Higgs decays. The results of recent searches on 13 TeV pp data from the LHC, their interplay and interpretation will be presented.

Speaker: James Frost (University of Oxford (GB))

LeptonPhoton23.pdf

17:00 Status of, and first data from, the milliQan Run 3 Detector

We will present the operational status of the milliQan Run 3 detector, which was installed during the 2022-3 YETS and is presently being commissioned. We will available initial results from data obtained with Run 3 LHC Collisions.

Speaker: Chris Hill (Ohio State University (US))

milliQan_LP_2023_chill_v2.pdf

milliQan_LP_2023_chill_v2.pptx

17:15 Dark sector and Axion-like particle search at BESIII

Axion-like particles (ALPs) are pseudo-Goldstone bosons arising from some spontaneously broken global symmetry, addressing the strong CP or hierarchy problems. The BESIII experiment is a symmetric e+e- collider operating at c.m. energy from 2.0 to 4.95 GeV. With the world’s largest data set of $J/\psi$ (10 Billion), $\psi(2S)$ (2.6 Billion), and about 25 fb-1 scan data from 3.77 to 4.95 GeV, we are able to search various dark sectors particles produced in e+e- annihilation and meson decay processes. In this talk, we report the search for dark photon candidate in $e^+e^- \to \gamma A’$ with invisible decay. The invisible decay of a light Higgs boson $A^0$ in $J/\psi \to \gamma A^0$ and in $\Lambda/\Lambda_c$ decays is also searched. In addition we perform searches for an Axion-like particle with mass O(GeV) in $J/\psi \to \gamma A$, with $A \to \gamma gamma$.

Speaker: Vindhyawasini Prasad

VPrasad_talk-LP2023V2.pdf

15:45 → 17:30 Detectors and facilities: Room D

Convener: Yuki Fujii (Monash University (AU))

15:45 Detector challenges of the strong-field QED experiment LUXE at the European XFEL

The LUXE experiment aims at studying high-field QED in electron-laser and photon-laser interactions, with the 16.5 GeV electron beam of the European XFEL and a laser beam with power of up to 350 TW. The experiment will measure the spectra of electrons, positrons and photons in expected ranges of $10^{-3}$ to $10^9$ per 1 Hz bunch crossing, depending on the laser power and focus. These measurements have to be performed in the presence of low-energy high radiation-background. To meet these challenges, for high-rate electron and photon fluxes, the experiment will use Cherenkov radiation detectors, scintillator screens, sapphire sensors, as well as lead-glass monitors for backscattering off the beam-dump. A four-layer silicon-pixel tracker and a compact electromagnetic tungsten calorimeter will be used to measure the positron spectra. The layout of the experiment and the expected performance under the harsh radiation conditions will be presented. The experiment has received stage 1 critical approval (CD1) from the DESY management and is in the process of preparing its technical design report (TDR). It is expected to start running in 2025/6.

Speaker: Thomas Schoerner-Sadenius (Deutsches Elektronen-Synchrotron (DE))

LUXE-Detector.LP23.TS.final.pdf

LUXE-Detector.LP23.TS.final.pptx

16:00 Key technologies in the design and construction of the JUNO central detector

The Jiangmen Underground Neutrino Observatory (JUNO) is a multipurpose neutrino experiment designed to determine neutrino mass hierarchy and precisely measure oscillation parameters by detecting reactor neutrinos from nuclear power plants, observe supernova neutrinos, study the atmospheric, solar neutrinos and geo-neutrinos, and perform exotic searches. The experiment is designed to use the liquid scintillator detector with large scale to have huge target mass and with the critical performance of the precise energy resolution.
The central detector(CD) is designed to have the relative energy resolution of 3% at 1 MeV with 20 ktons of liquid scintillator. The liquid scintillator is contained by an acrylic spherical vessel with a diameter of 35.4 m, and the acrylic vessel is supported by a stainless steel latticed shell that also holds about 17600 pieces of 20 inch PMTs and 25600 pieces of 3 inch PMTs to detect the light from the liquid scintillator. The detector is immersed in pure water, so the acrylic vessel needs to bear more than 3000 tons of buoyancy.
At present, the detector is under construction, and many challenges have been encountered in the design and construction of the detector. For example, the acrylic ball needs to bear thousands of tons of buoyancy, the acrylic bonding face cracks during annealing, the stainless steel latticed shell adopts ring-groove rivets to ensure the installation size, PMT is densely installed inside the shell, and so on. This talk will introduce the recent status of the detector and key technologies in its design and construction.

Speaker: Xiaohui Qian (IHEP.CAS)

Key technologies of JUNO central detector-xiaohui202306.pdf

16:15 Search for high mass dark matter axion at IBS-CAPP

The axion is a hypothetical pseudo-Goldstone boson proposed to naturally resolve the strong CP problem, a long-standing mystery in the topological vacuum structure of quantum chromodynamics (QCD). In particular, the QCD axions with masses on the order of $\mu$eV to meV are a strong candidate for dark matter. The cavity haloscope is one of the most effective to search for dark matter axions in the microwave region. A large cavity volume and low detector noise are crucial for high-frequency axion searches to improve experimental performance. Various novel cavity designs (based on multiple cells design, wheel mechanism, and tunable photonic crystals) have been proposed by IBS-CAPP for efficient searches for high-mass axions. Josephson parametric amplifiers developed by U. of Tokyo/RIKEN achieved near-quantum-limited performance. Utilizing these key components, CAPP is currently conducting leading haloscope experiments to explore the frequency range between 5 GHz and 25 GHz (20 $\mu$eV and 100 $\mu$eV) with KSVZ sensitivity. In this talk, we present the current status of these experiments is presented and discuss future plans.

Speaker: Dr Younggeun Kim (Center for Axion and Precision Physics Research, Institute for Basic Science)

Lepton_Photon23_YounggeunKim.pptx

16:30 Overview of the FCC Program

The 2020 visionary update of the European Strategy for Particle Physics endorsing the FCC feasibility study as a top priority for CERN and its international partners provides the HEP community with a powerful tool of investigations. As an essential and complementary step towards a 100 TeV hadron collider, the FCC will first feature an e+e- collider (FCC-ee). The very high luminosity, the exquisite energy calibration at the Z, WW, ZH and ttbar energies, the possibility of monochromatisation at √s = mH, and the multiple detectors are building blocks of a unique program for FCC-ee, with high potential for discoveries. Such a machine offers ideal conditions for the study of the four heavy particles of the standard model with a flurry of opportunities for precision measurements, the observation of tiny violations of established symmetries, the searches for rare or forbidden processes, and the exploration of the dark sector with the possible discovery of feebly coupled particles. A digest of this diverse and rich physics programme and of the corresponding experimental and theoretical challenges will be given in this presentation.

Speaker: Heather Gray (UC Berkeley/LBNL)

hgray_FCC_leptonphoton.pdf

16:45 ATLAS Trigger and Data Acquisition Upgrades for the High Luminosity LHC

The ATLAS experiment at CERN is constructing upgraded system for the "High Luminosity LHC", with collisions due to start in 2029. In order to deliver an order of magnitude more data than previous LHC runs, 14 TeV protons will collide with an instantaneous luminosity of up to 7.5 x 10e34 cm^-2s^-1, resulting in much higher pileup and data rates than the current experiment was designed to handle. While this is essential to realise the physics programme, it presents a huge challenge for the detector, trigger, data acquisition and computing. The detector upgrades themselves also present new requirements and opportunities for the trigger and data acquisition system. The design of the TDAQ upgrade comprises: a hardware-based low-latency real-time Trigger operating at 40 MHz, Data Acquisition which combines custom readout with commodity hardware and networking to deal with 4.6 TB/s input, and an Event Filter running at 1 MHz which combines offline-like algorithms on a large commodity compute service with the potential to be augmented by commercial accelerators . Commodity servers and networks are used as far as possible, with custom ATCA boards, high speed links and powerful FPGAs deployed in the low-latency parts of the system. Offline-style clustering and jet-finding in FPGAs, and accelerated track reconstruction are designed to combat pileup in the Trigger and Event Filter respectively. This contribution will report recent progress on the design, technology and construction of the system. The physics motivation and expected performance will be shown for key physics processes.

Speaker: Revital Kopeliansky (Indiana University (US))

ATL-COM-DAQ-2023-044.pdf

15:45 → 17:30 Flavour: Clarendon Auditorium

Convener: German Valencia (Monash University (AU))

15:45 Model-independent extraction of form-factors and $|V_{cb}|$ in $\overline{B}\to D\ell^- \overline{\nu_\ell}$ with hadronic tagging at $BABAR$

Employing the full $BABAR$ dataset, the first two-dimensional unbinned angular analysis of the semileptonic decay $\overline{B}\to D\ell^- \overline{\nu_\ell}$ is performed in both $q^2$ and lepton helicity angle, making use of the hadronic reconstruction of the tag-side $B$ meson. Here $\ell$ stands for an electron or a muon. A novel data-driven signal-background separation procedure with minimal dependence on simulation is developed, that preserves all multi-dimensional correlations present in the data.
Including input from latest lattice QCD and previously available experimental data, the underlying form-factors are extracted in both model-dependent and independent methods. The CKM matrix element $|V_{cb}|$ and the SM prediction of the lepton-flavor universality violation variable R(D) are extracted.

Speaker: Gerald Eigen (University of Bergen (NO))

GE-LP23.pdf

16:00 Measurements of the CKM angle gamma at LHCb

The tree-level determination of the CKM angle gamma is a standard candle measurement of CP violation in the Standard Model. The latest LHCb results from time-integrated measurements of CP violation using beauty to open charm decays are presented. These include updates to previous Run 1 measurements using the full LHCb Run 1+2 data sample, measurements using new decay channels, and the latest LHCb gamma & charm mixing combination.

Speaker: Fidan Suljik (University of Oxford (GB))

LeptonPhoton2023_FidanSuljik.pdf

16:15 Heavy flavour production and spectroscopy at LHCb

Running coupling of QCD results in totally different behavior of the strong interaction in high- and low-energy regions. Experimental measurements in both regions are important test on knowledge of the strong process, and help to understand the QCD backgrounds in New Physics searches using electro-weak processes. The large heavy flavor cross section in proton-proton collisions at the LHC and the high-efficient beauty and charm reconstruction of the LHCb detector make the LHCb experiment a unique platform to study the heavy flavor production and spectroscopy, which are sensitive tags to the strong interaction at high- (perturbative) and low-energy (nonperturbative) regions, respectively. In this presentation the latest results on the heavy flavour production and spectroscopy from the LHCb experiment will be reported.

Speaker: Yixiong Zhou (University of Chinese Academy of Sciences (CN))

LeptonPhoton2023_heavyflavor_production_spectroscopy_LHCb.pdf

16:30 ATLAS measurements of charm and B hadron production and properties

This talk will discuss recent results from the proton-proton collision data taken by the ATLAS experiment on the production of charm and B hadrons and their properties. Measurements of J/ψ, ψ(2S), Ds, and B+ differential production cross sections at 13 TeV will be reported. Results on the associated production of the J/ψ with other particles will be shown. Measurements of the B0 lifetime and the Bs→μμ effective lifetime will be presented.

Speakers: Sally Seidel (University of New Mexico (US)), Sally Seidel, Sally Seidel (University of New Mexico / ATLAS)

lepton-photon-2023-upload-for-ATLAS-approval-update2.pdf

16:45 ATLAS results on exotic hadronic resonance

Recent searches for exotic resonances performed with the Run 2 proton-proton collision data taken by the ATLAS experiment will be presented. This will include studies of Zc and Zcs states in B-meson decays and searches for exotic resonances in 4 muon final states.

Speaker: Darren Price (University of Manchester (GB))

dprice_LeptonPhoton23_FourMuon.pdf

17:00 Recent Belle II results on hadronic B decays

The investigation of $B$-meson decays into charmed and charmless hadronic final states is a keystone of the Belle II program. It offers theoretically reliable and experimentally precise constraints on CKM unitarity, it is sensitive to effects from non-SM physics, and it furthers knowledge about uncharted $b \to c$ hadronic transitions. Recent results on branching ratios and direct CP-violating asymmetries of $B \to K \pi$ decays are presented that lead to world-leading tests of the SM based on the $K \pi$ isospin sum rule. First observations of new $B \to D^{(*)}KK_S$ decays and new results from combined analyses of Belle and Belle II data to determine the CKM angle $\phi_3$ (or $\gamma$) are also presented.

Speaker: Xiaodong Shi (KEK)

xiaodong-LP2023.pdf

17:15 Recent quarkonium results at Belle II

Belle II offers unique possibilities for the discovery and interpretation of exotic multiquark states to probe the fundamentals of QCD. This talk presents recent results on searches for the hidden bottom transition between $\Upsilon(10750)$ and $\chi_{bJ}$, and measurements of the energy dependence of the $e^+e^- \to B^{(*)} \bar B ^{(*)}$ cross section.

Speaker: Yang Li (Fudan University)

LP_Belle2_Quarkonium.pdf

Wednesday 19 July

09:00 → 11:00 BSM: Room C

Convener: Valentina Cairo (CERN)

09:00 Phenomenology of low-scale seesaw with flavour and CP symmetries

We consider a type-I seesaw framework endowed with a flavour symmetry, belonging to the series of non-abelian groups Delta (3 n^2) and Delta (6 n^2), and a CP symmetry. Breaking these symmetries in a non-trivial way results in the right-handed neutrinos being degenerate in mass up to possible (further symmetry-breaking) splittings, while the neutrino Yukawa coupling matrix encodes the entire flavour structure in the neutrino sector. For a fixed combination of flavour and CP symmetry and residual groups, this matrix contains five real free parameters. Four of them are determined by the light neutrino mass spectrum and by accommodating experimental data on lepton mixing well, while the fifth parameter is related to right-handed neutrinos. We scrutinise for all four types of lepton mixing patterns the potential to generate the baryon asymmetry of the Universe through low-scale leptogenesis numerically and analytically as well as the possibility to directly search for the heavy neutrinos.

Speaker: Claudia Hagedorn

Hagedorn_LP2023.pdf

09:15 Vector boson scattering measurements in ATLAS

Measurements of diboson production in association with two additional jets at the LHC probe interactions between electroweak vector bosons predicted by the Standard Model and test contributions from anomalous quartic couplings. In this talk, the production of same-sign as well as opposite-sign WW production through vector boson scattering will be presented. Electroweak production of pairs of Z bosons and Z+y will also be discussed. Finally, a new measurement exploring semileptonic decays of boson pairs produced in association to two jets will be highlighted. Where applicable, differential measurements are presented and are used to set limits on dimension-8 effective field theory operators.

Speaker: Shu Li (Tsung-Dao Lee Institute (CN) & Shanghai Jiao Tong Univ. (CN))

VBSforATLAS-LeptonPhoton2023.pdf

09:30 Searches for electroweak SUSY and compressed SUSY spectra from CMS

A wide variety of searches for Supersymmetry have been performed by experiments at the Large Hadron Collider. In this talk, we focus on searches for electroweak production of Supersymmetric particles and searches for Supersymmetric particles in compressed spectra. The results are obtained from the proton-proton collision data with luminosity up to 138 fb^{-1} at the center of mass energy of 13 TeV collected during the LHC Run 2.

Speaker: Harjot Kaur (Panjab University (IN))

HarjotKaur_LP2023.pdf

09:45 Searches for additional scalars with two photons in the final state at CMS

Although the Higgs boson discovered is so far compatible with the Standard Model Higgs boson, within the experimental uncertainties there is still room for BSM (such as 2HDM and NMSSM) which allow the presence of a Higgs boson with a mass lighter than the discovered Higgs boson. Some latest results of the searches for additional Higgs bosons with two photons included in the final state at CMS will be presented. The searches include a search for a standard model-like Higgs boson in the mass range between 70 and 110 GeV in the diphoton final state, and for a Higgs boson decaying into scalar(s) with at least one scalar decaying into two photons. Some of these searches are performed for the first time based on all LHC data collected by CMS at a center-of-mass energy of 13 TeV.

Speaker: Junquan Tao (Institute of High Energy Physics, Chinese Academy of Sciences (CN))

LP2023_CMSAdditionalScalarPhotons_JTao.pdf

10:00 Searches for new physics in CMS in events with jets, leptons and photons in the final state

Many new physics models, e.g., compositeness, extra dimensions, extended Higgs sectors, supersymmetric theories, and dark sector extensions, are expected to manifest themselves in the final states with leptons and photons. This talk presents searches in CMS for new phenomena in the final states that include leptons and photons, focusing on the recent results obtained using the full Run-II data-set collected at the LHC.

Speaker: Andrew Evan Hart (Rutgers State Univ. of New Jersey (US))

lp_20230719.pdf

10:15 Searches for BSM resonances in ATLAS

Many new physics models predict the existence of new particles. This talk summarizes recent ATLAS searches for Beyond-the-Standard-Model heavy resonances which decay to pairs of bosons, heavy quarks, or leptons, using Run 2 data collected at the LHC. The experimental methods are explained, including the jet substructure techniques used in some searches to disentangle the hadronic decay products in highly boosted configurations.

Speaker: Makayla Vessella 🐏 (University of Massachusetts (US))

LP2023 ATLAS BSM Resonances.pdf

10:30 Probing the nature of electroweak symmetry breaking with Higgs boson pairs in ATLAS

In the Standard Model, the ground state of the Higgs field is not found at zero but instead corresponds to one of the degenerate solutions minimising the Higgs potential. In turn, this spontaneous electroweak symmetry breaking provides a mechanism for the mass generation of nearly all fundamental particles. The Standard Model makes a definite prediction for the Higgs boson self-coupling and thereby the shape of the Higgs potential. Experimentally, both can be probed through the production of Higgs boson pairs (HH), a rare process that presently receives a lot of attention at the LHC. In this talk, the latest HH searches by the ATLAS experiment are reported, with emphasis on the results obtained with the full LHC Run 2 dataset at 13 TeV. Non-resonant HH search results are interpreted both in terms of sensitivity to the Standard Model and as limits on the Higgs boson self-coupling and the quartic VVHH coupling. The Higgs boson self-coupling can be also constrained by exploiting higher-order electroweak corrections to single Higgs boson production. A combined measurement of both results yields the overall highest precision, and reduces model dependence by allowing for the simultaneous determination of the single Higgs boson couplings. Results for this combined measurement are also presented. Finally, extrapolations of recent HH results towards the High Luminosity LHC upgrade are also discussed.

Speaker: Yu Nakahama Higuchi (High Energy Accelerator Research Organization (JP))

Nakahama_LP2023.pdf

09:00 → 10:45 Dark Matter: Room E

Convener: Dr Peter Cox (The University of Melbourne)

09:00 Resolving the DAMA Debate: Dark Matter Search using NaI(Tl) detectors beyond DAMA

The DAMA collaboration's claim of detecting dark matter in the early 2000s remained a long-standing anomaly, and subsequent hypotheses were disproven using different targets. More recently, the COSINE and ANAIS collaboration utilized the same NaI(Tl) target and found that dark matter was not the source of the annual modulation observed by the DAMA collaboration. This presentation will provide an overview of the current status of the COSINE experiment, as well as the latest advancements in NaI(Tl) research for dark matter search beyond the DAMA era.

Speaker: Govinda Adhikari (Yale University)

Lepton_cosine_stattus_govinda.pdf

09:15 LZ status

LUX-ZEPLIN (LZ) is a dark matter direct detection experiment located at the Sanford Underground Research Facility in Lead, South Dakota. At the heart of the detector is a dual-phase time projection chamber containing 7 tonnes of active liquid xenon. During its 1000-day science run, LZ aims to achieve unprecedented sensitivity to Weakly Interacting Massive Particles (WIMPs) down to a WIMP-nucleon spin-independent cross section of about $1.4 \times 10^{-48} \textrm{cm}^{2}$ for a $40 \textrm{GeV}/\textrm{c}^{2}$ mass WIMP. In this talk, I will give an overview of the LZ experiment, report on its first dark matter search results and discuss its current status.

Speaker: Theresa Fruth (University of Sydney)

2023LeptonPhoton_LZStatus_Fruth.pdf

09:30 Search for dark matter induced event rate modulation in DarkSide-50 ionization signal

DarkSide-50 is a direct dark matter search experiment using a dual phase argon time projection chamber at LNGS in Italy. Based solely on the ionization spectrum, it has set the most stringent exclusion limits for several low-mass dark matter candidates. Owing to its peculiar behaviour, dark matter can be searched in a model-independent way exploiting the expected fluctuation of the relative velocity between dark matter and the Earth. In this talk, we present the first search of such an event rate modulation with argon using the DarkSide-50 ionization signal. Stable operation of the detector over years, as well as a good understanding of the detector response, allowed us to achieve the lowest energy threshold ever achieved in this kind of experiments of the order of sub-keV. Comparison with the other results from xenon or NaI based experiments will be also discussed.

Speaker: Masato Kimura (AstroCeNT, CAMK/PAN)

leptonphoton23.pdf

09:45 Inelastic nuclear scattering of neutrinos and dark matter

Pion decay-at-rest neutrino experiments could also be a copius source of dark sector particles. Experiments looking for the elastic scattering of neutrinos may also be sensitive to decay of nuclei excited by inelastic scattering of both neutrinos and dark matter. Using this channel, with an additional timing cut to reduce the neutrino background, we demonstrate an increased sensitivity to a dark photon portal DM model compared to the existing constraints. With ongoing experiments, world-leading constraints on this parameter space will be obtained.

Speaker: Jayden Newstead (University of Melbourne)

JLN_Lepton-photon_2023.pptx

10:00 CYGNUS-Oz: Australian R&D for a future CYGNUS network of directional dark matter detectors

The detection limits for WIMP-nucleon scattering are approaching the neutrino floor where coherent neutrino-nucleus scattering will form an irreducible background for many of the dark matter detector technologies currently in use. CYGNUS is a network of international research groups who aim to use directional detection as a means to penetrate the neutrino floor. Their current focus is R&D aimed at optimising gas Time Projection Chambers (TPCs) to achieve low energy thresholds and excellent nuclear recoil track reconstruction, so as to image the recoil tracks caused by WIMP interactions. The long-term goal is to combine results from a network of underground gas TPCs to make a large-scale distributed observatory for nuclear and electron recoils.

Australian researchers have recently formalised the CYGNUS-Oz collaboration so as to concentrate the Australian CYGNUS efforts. A prototype gas TPC is being developed with the ability to handle mixes of up to 3 different gases, and a Gas Electron Multiplier (GEM) amplification stage with wire readout to observe the ionisation track created by a recoiling nucleus within the gas volume. The time of arrival of the charge provides information on the z-component of the track, with limited x-resolution from the wire readout. A photomultiplier tube observes the light from the track ionisation and will be used to gate an intensified camera that will provide high-resolution x-y track information by imaging the scintillation light generated in the avalanche region of the GEMs.

This presentation will present results obtained with the CYGNUS-Oz prototype and also review some of the recent work carried out by the broader CYGNUS collaboration. This includes detector R&D and results from conceptual design studies that discuss the detection limits that can be achieved for both neutrinos and WIMP dark matter, depending on the technological approaches/limits, especially in terms of track reconstruction accuracy and energy thresholds.

Speaker: Lachlan McKie (Australian National University)

CYGNUSOz_LeptonPhoton23.pptx

10:15 Precise predictions and new insights for atomic ionisation from the Migdal effect

The scattering of neutral particles by an atomic nucleus can lead to electronic ionisation and excitation through a process known as the Migdal effect. We revisit and improve upon previous calculations of the Migdal effect, using the Dirac-Hartree-Fock method to calculate the atomic wavefunctions. Our methods do not rely on the use of the dipole approximation, allowing us to present robust results for higher nuclear recoil velocities than was previously possible. Our calculations provide the theoretical foundations for future measurements of the Migdal effect using neutron sources, and searches for dark matter in direct detection experiments. We show that multiple ionisation must be taken into account in experiments with fast neutrons, and derive the semi-inclusive probability for processes that yield a hard electron above a defined energy threshold. We present projections for the capabilities of future liquid noble element-based detectors doped with hydrogen in order to increase their reach at low dark matter masses.

Speaker: Prof. Matthew Dolan (University of Melbourne)

10:30 Probing new physics at the LUXE experiment

The proposed LUXE experiment (LASER Und XFEL Experiment) at DESY, Hamburg, using the electron beam from the European XFEL, aims to probe QED in the non-perturbative regime created in collisions between high-intensity laser pulses and high-energy electron or photon beams. This setup also provides a unique opportunity to probe physics beyond the standard model. In this talk we show that by leveraging the large photon flux generated at LUXE, one can probe axion-like-particles (ALPs) up to a mass of 350 MeV and with photon coupling of $3\times10^{-6}$ GeV$^{-1}$. This reach is comparable to the background-free projection from NA62. In addition, we will discuss other probes of new physics such as ALPs-electron coupling.

Speaker: Thomas Schoerner-Sadenius (Deutsches Elektronen-Synchrotron (DE))

LUXE-BSM.LP23.TS.final.pdf

LUXE-BSM.LP23.TS.final.pptx

09:00 → 10:45 Detectors and facilities: Room D

Convener: Tom Hadavizadeh (Monash University (AU))

09:00 Measurement of beam polarization at an $e^+e^-$ $B$-Factory with a new tau polarimetry technique

Belle II is considering upgrading SuperKEKB with a polarized electron beam. The introduction of beam polarization to the experiment would significantly expand the physics program of Belle II in the electroweak, dark , and lepton flavor universality sectors. For all of these future measurements a robust method of determining the average beam polarization is required to maximize the level of precision. The $BABAR$ experiment has developed a new beam polarimetry technique, Tau Polarimetry, capable of measuring the average beam polarization to better than half a percent. Tau Polarimetry strongly motivates the addition of beam polarization to SuperKEKB and could also be used at future $e^+e^-$ colliders such as the ILC. We present the performances of this method through an analysis of the full data set of about 470 $\text{fb}^{-1}$ collected at the $e^+e^-$ PEP-II collider by the $BABAR$ detector.

Speaker: Gerald Eigen (University of Bergen (NO))

2023_TauPol_LP-v2.pdf

09:15 Future Charged lepton flavor violation muon program

Flavor physics holds great potential to investigate fundamental aspects of the standard model such as mass hierarchy, electro weak symmetry breaking and more. Within this physics frontier, charged lepton flavor violation (CLFV) is a phenomenon that is highly suppressed in the standard model and an excellent probe of new physics. Current generation CLFV experiments like Mu2e, COMET, MEG and Mu3e are gearing up for data taking within the decade. The "Advanced Muon Facility" has been recently proposed to take full advantage of the PIP-II beamline at Fermilab to produce the world’s most intense positive and negative muon beams. This complex would enable a broad muon physics program, including studies of charged lepton flavor violation and muonium-antimuonium transitions. This talk will describe the proposed facility, the associated physics program, and the main R&D challenges.

Speaker: Mete Yucel

MeteYucel_AMF.pdf

09:30 The COMET experiment: A search for muon-to-electron conversion at J-PARC

The COMET Experiment at J-PARC aims to search for the lepton-flavour violating process of muon to electron conversion in a muonic atom, $\mu^{-}N \rightarrow \mathrm{e}^{-}N$, with a 90% confidence level branching-ratio limit of $6\times 10^{−17}$, in order to explore the parameter region predicted by most well-motivated theoretical models beyond the Standard Model. The need for this sensitivity places several stringent requirements on both the muon beam and the detector system. In order to realize the experiment effectively and timely, a staged approach to deployment is employed, and the COMET Phase-I experiment will commence engineering runs in 2025. At the Phase-I experiment, a precise muon-beam measurement will be conducted, and a search for $\mu^{-}N \rightarrow \mathrm{e}^{-}N$ will also be carried out with an intermediate sensitivity of $7\times 10^{−15}$ (90% CL upper limit). In this paper, the current status of R&D and construction of the experiment is presented in addition to the experimental overview.

Speaker: Hajime Nishiguchi

LeptonPhoton2023_Nishiguchi.pdf

09:45 The Mu2e Experiment

The Mu2e experiment is currently being assembled at Fermilab for its first beam in 2025. This experiment will search for the Standard Model violating neutrinoless conversion of a muon into an electron by detecting the delayed, essentially monoenergetic electron from a muon trapped in an Aluminum atom. The goal is to search for this signal at a rate approximately four orders of magnitude beyond current experimental limits. If found, these electrons are an unambiguous signal for physics beyond the Standard Model. This talk will give a brief description of the Mu2e experiment and an update of its progress toward data taking.

Speaker: Prof. Kenneth Heller (University of Minnesota)

Mu2e Lepton Photon talk KH.pdf

Mu2e Lepton Photon talk KH.pptx

10:00 The Belle II Upgrade Program

The Belle II experiment at the SuperKEKB e+e- collider has started data taking in 2019 with the perspective of collecting 50ab$^{-1}$ in the course of the next several years. The wealth of physics results obtained with the current data sample of about 400fb$^{-1}$ is showing that the detector is working well with very good performance, but the first years of running are also showing novel challenges and opportunities for reliable and efficient detector operations with machine backgrounds extrapolated to full luminosity. For this reason, and also considering that an accelerator consolidation and upgrade shutdown is being studied for the timeframe of 2027-2028 to reach the target luminosity of $6\times 10^{35} \mathrm{cm^{-2}s^{-1}}$, Belle II is defining a detector upgrade program to make the various sub-detectors more robust and performant even in the presence of high backgrounds, facilitating the SuperKEKB running at high luminosity.
This upgrade program will possibly include the replacement of some readout electronics, the upgrade of some detector elements, and may also involve the substitution of entire detector sub-systems such as the vertex detector. A Conceptual Design Report is currently planned for mid 2023. This paper will cover the full range of proposed upgrade ideas and their development plans.

Speaker: Prof. Leo Piilonen (Virginia Tech)

Belle2Upgrade-Piilonen.pdf

Belle2Upgrade-Piilonen.pptx

10:15 COMET Phase-Alpha Experiment to Investigate COMET's New Muon Beamline at J-PARC

The COMET Phase-I and -II experiments will search for the muon-to-electron conversion process with a sensitivity improving the current upper limit on its branching ratio by a factor of 100 and 10000, respectively. An observation will be a splendid sign of the existence of physics beyond the standard model. The experiment utilises the world's highest-intense proton beam of J-PARC in Japan to generate a considerable number of muons from a fixed pion-production target through pion decays, and its secondary muon beamline is being constructed. In particular, the Transport Solenoid (TS), a bent solenoidal magnet, plays the most crucial role in transporting muons and separating them with their sign of charge and momentum amplitude. In order to study the muon beam and its transport, the COMET collaboration carried out an experiment called Phase-$\alpha$ in February and March of 2023.
Phase-$\alpha$ aims to inject J-PARC’s proton beam to the COMET beamline for the first time, profile on the beam transported by the TS, and validate COMET's official simulation tool and data. We developed three detectors as follows. First, Muon Beam Monitor is a scintillating plastic fibre horoscope detector to measure the position and timing of the beam particles. Second, Straw Tube Tracker is a tracker with gaseous proportional chambers to measure its position and direction. Third, Range Counter is a series of scintillating plastic plates to count negative muons in the beam and identify positive pions. It also consists of a copper absorber plate, that lets negative muons stop and decay in it with a much shorter lifetime to be counted separately from other muons, and graphite plates to degrade muons' momentum and control their initial momentum to stop in the absorber.
We also installed $\rm TiO_2$ sensors to measure the primary protons and a beam-masking device in front of the TS to control the initial phase spaces of the transported secondary beam for a detailed investigation of the beam transport along the TS.
We succeeded in observing muon beams transported by the TS in the experiment and collected several datasets valuable to study its details, and the data analysis just began. This talk will present the details of the facility, experiment, and detectors, and show some preliminary results.

Speaker: Kou Oishi

230719_LeptonPhoton2023_KouOishi_Light.pdf

09:00 → 10:45 Flavour: Clarendon Auditorium

Convener: Jake Lane (Monash University (AU))

09:15 Searches and tests for lepton-flavour-violating processes at CMS

New physics can manifest itself via lepton-flavour-violating processes in LHC proton-proton collisions. This talk summaries the most recent searches for lepton-flavour-violating processes and tests of lepton flavour universality with the CMS detector, using proton-proton collisions at a centre-of-mass energy of 13 TeV.

Speaker: Luigi Marchese (ETH Zurich (CH))

marchese.pdf

09:30 Probing New Physics Effects in $b\to sll'$ transitions

Continued attempts to find new physics beyond the standard model remains elusive. In this context, we focus on long standing discrepancies between the theory and experiments, mediated by FCNC $b\to s ll$ quark level transitions. In particular, we consider discrepancies observed by LHCb experiment in BR ($B_s \to \phi ll$), which has deviations at the level of 3.6 $\sigma$. Additionally, standard deviation of 3.3 $\sigma$ and 1.2 $\sigma$, respectively for $P_{5’}$ in $B\to K^* \mu^+ \mu^-$ and the branching ratio in $B_s \to \mu^+\mu^-$ processes are also observed. We find out the constraints on the new physics coupling parameters in the presence of a non-universal $Z’$ model. We then probe the exclusive leptonic decay channels $B_{s} \to ll’$, $ B_{(s)} \to (K^{(*)}, \phi, f_2’, K_2^{*} ) ll’ $ induced by the neutral current transition $b\to sll'$. Thereafter, we find that the $q^2$ variation of the observables, such as, branching ratio, forward-backward asymmetry, lepton polarization asymmetry, and the very sensible observable, so called non-universality observables for LFV decays, display interesting sensitivity of new physics parameters. Furthermore, implications for rare charm decays in this framework are discussed. These findings along with more results from experiments will be crucial in our quest for the nature of new physics beyond the standard model.

Speaker: Anjan Giri

LP-23.pdf

09:45 Angular distribution of Lb --> pK-l+l- decays comprising Λ resonances with spin ≤ 5/2

The Lb --> pK-l+l- decays are governed by the b --> sl+l- quark level transitions. Such decays received significant attention in past decade and over time showed some discrepancies with the Standard model. While analogous meson decays are well studied, Lb baryons received significantly less attention. Phenomenology of Lb FCNC decays is well explored for decays with ground state Lambda baryon and for some cases of isolated Lambda resonance. In this work we present full angular distribution for a case of several interfering Lambda resonances up to spin 5/2. We will explore full set of observables, some of which have strong sensitivity to new physics. Some of these are largely insensitive to the details of interference between resonances, while interpretation of others will require full understanding of which resonances contributes and strong phases between them. Several new observables, which are purely due to the interference between resonances, are largely insensitive to the new physics, but allow powerful tests of form-factors descriptions.

Speaker: Michal Kreps (University of Warwick (GB))

LP2023.pdf

10:00 Tests of Lepton Flavour Universality and searches for Lepton Flavour Violation at LHCb

Rare B-hadron decays mediated by b-> sll transitions provide a sensitive test of Lepton Flavour Universality (LFU), a symmetry of the Standard Model by which the coupling of the electroweak gauge bosons to leptons is flavour universal. Extensions of the SM do not necessarily preserve this symmetry and may give sizable contributions to these processes. Precise measurements of LFU ratios are, therefore, an extremely sensitive probe for New Physics. Likewise, breaking of LFU can result in Lepton-Flavour violating decays of the form b->s\ell\ell'. This talks summarizes recent measurements of Lepton Flavour Universality at LHCb, as well as searches for Lepton-Flavour violating decays.

Speaker: Biljana Mitreska (Technische Universitaet Dortmund (DE))

LeptonPhoton_2023_Mitreska_v1.pdf

10:15 Measurements of $b\to s\mu^+\mu^- $ processes at LHCb

Flavour-Changing Neutral-Current processes, such as decays mediated by $b\to s\mu^+\mu^-$ transitions, are forbidden at the lowest perturbative order in the Standard Model (SM) and hence might receive comparatively large corrections from new particles in SM extensions. These corrections may affect different observables related to these decays such as branching fractions or angular distributions. The most recent results on $b\to s\mu^+\mu^-$ decays from LHCb will be presented

Speaker: J Alexander Ward (University of Warwick (GB))

b2smumu_at_lhcb_LeptonPhoton2023.pdf

10:30 Recent Belle II results on radiative and electroweak penguin decays

Decays of B mesons that proceed through radiative penguin amplitudes probe a large class of generic non-SM models for which Belle II has unique reach. We present recent results from an inclusive $b \to s \gamma$ analysis and a $B \to \rho \gamma$ analysis. In addition, we report results on $b \to s \ell^+ \ell^-$ decays of B mesons, which proceed through electroweak penguin amplitudes and offer multiple probes of non-SM physics.

Speaker: Niharika Rout

Lepton-Photon_2023_NR.pdf

10:45 → 11:05 Break

11:05 → 12:50 Collider Precision: Clarendon Auditorium

11:05 Precision Predictions in Top-quark Width

We will present our recent work on the first full analytic results of NNLO QCD corrections to the top-quark decay in the Standard Model by applying the optical theorem to three-loop self-energy diagrams. The results are expressed in terms of harmonic polylogarithms. We also analytically compute the decay width including the off-shell $W$ boson effect up to NNLO in QCD for the first time. Combining these contributions with electroweak corrections and the finite $b$-quark mass effect, we determine the most precise top-quark width to be 1.331 GeV for $m_t=172.69$ GeV. The total theoretical uncertainties including those from renormalization scale choice, top-quark mass renormalization scheme, input parameters, and missing higher-order corrections are scrutinized and found to be less than $1\%$. All the formulae are incorporated in a portable Mathematica program TopWidth (https://github.com/haitaoli1/TopWidth).

Speaker: Haitao Li (Shandong University)

haitao_lepton-photon2023.pdf

11:20 Precision measurements of W and Z production at ATLAS

Precision measurements of the production cross-sections of W and Z boson at LHC provide important tests of perturbative QCD and information about the parton distribution functions for quarks within the proton. This talk will present extraordinarily precise double-differential measurement of the Z boson transverse momentum and rapidity at a centre-of-mass energy of 8 TeV. From these results, the strong coupling constant is determined. Moreover, the transverse momentum of the W and Z boson measured from the hadronic recoil at 5 and 13 TeV are discussed. If ready, the talk concludes with a presentation of precision studies of the Drell-Yan process at low and high invariant mass.

Speaker: Zhibo Wu (Université Paris-Saclay (FR), University of Science and Technology of China (CN))

ZhiboWu_LP2023_v4.pdf

11:35 First observation of production of four top quark in the multi-lepton channel with the CMS Run 2 dataset

The production of four top quarks (tttt) is studied as a rare standard model process with sensitivity to new physics. The four top quark production cross section also allows investigations of virtual Higgs boson production and the top quark Yukawa coupling, EFT interpretations, and is an essential test of Quantum Chromodynamics. This presentation summarises the recent observation for four top quark production with LHC Run 2 data samples collected by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to integrated luminosities of up to 138 fb−1. The signal is identified using either same-sign dileptons or multi-leptons. Boosted decision trees are used for both lepton identification and signal to background separation. Several orthogonal datasets are used to estimate the backgrounds and control their systematic uncertainties.

Speaker: Didar Dobur (Ghent University (BE))

Lepton_Photon_4Top_Dobur_Final.pdf

11:50 Measurements of Higgs boson properties (mass, width, and Spin/CP) with the ATLAS detector

This talk presents precise measurement of the properties of the Higgs boson, including its mass, total width, spin, and CP quantum number. The measurements are performed in various Higgs boson production and decay modes, as well as their combinations. Observation of deviations between these measurements and Standard Model (SM) predictions would be a sign of possible new phenomena beyond the SM.

Speaker: Trevor Vickey (University of Sheffield (GB))

TrevorVickey_LeptonPhoton_July_2023.pdf

12:05 Recent highlights of top-quark cross section and properties measurements with the ATLAS detector at the LHC

The remarkably large dataset collected with the ATLAS detector at the highest proton-proton collision energy provided by LHC allows to use the large sample of top quark events to test theoretical predictions with unprecedented precision. Recent measurements of total and differential top-quark cross sections as well properties of top-quark production are presented, including new measurements of top-quark pair production and single-top production at 5 and 13 TeV as well as first measurement of the 13.6 TeV cross-section of ttbar events. Further highlights are the new measurements of angular properties such as the W-boson polarisation in ttbar events, new top-quark mass measurements as well as distributions sensitive to colour reconnection. Several measurements are interpreted within the Standard Model Effective Field Theory, yielding stringent bounds on Wilson coefficients.

Speaker: Teresa Barillari (Max Planck Society (DE))

Teresa-LP2023-v1.pdf

12:20 Measurements of Higgs boson production and decay rates and their interpretation with the ATLAS experiment

The event rates and kinematics of Higgs boson production and decay processes at the LHC are sensitive probes of possible new phenomena beyond the Standard Model (BSM). This talk presents precise measurements of Higgs boson production and decay rates, obtained using the full Run 2 and partial Run 3 pp collision dataset collected by the ATLAS experiment at 13 TeV and 13.6 TeV. These include total and fiducial cross-sections for the main Higgs boson processes as well as branching ratios into final states with bosons and fermions. Differential cross-sections in a variety of observables are also reported, as well as a fine-grained description of the Higgs boson production kinematics within the Simplified Template Cross-section (STXS) framework. Combinations of such measurements are also presented, as well as their interpretation in terms of Higgs boson couplings and in the context of Effective Field Theory (EFT) frameworks and specific BSM models.

Speaker: Andrew Mehta (University of Liverpool (GB))

ATLAS Higgs.pdf

12:35 First evidence for the production of four top quarks in events with zero to two leptons with the CMS Run 2 dataset

The production of four top quarks ($t\bar{t}t\bar{t}$) is studied as a rare standard model process with sensitivity to new physics. The four top quark production cross section also allows investigations of virtual Higgs boson production and the top quark Yukawa coupling, EFT interpretations, and is an essential test of Quantum Chromodynamics. This presentation summarises the recent evidence for four top quark production with LHC Run 2 data samples collected by the CMS experiment at a center-of-mass energy of 13 TeV, corresponding to integrated luminosities of up to 138 fb$^{-1}$. The results will be presented for the final states with zero, one or two opposite-charged leptons, that all have substantial backgrounds from QCD and top quark pair production. This warrants the use of innovative machine learning techniques that have not yet been previously used in particle physics.

Speaker: Vichayanun Wachirapusitanand (Chulalongkorn University (TH))

Four Tops LP Conference FINAL 19 Jul 2023.pdf

11:05 → 12:50 Detectors and facilities: Room D

Convener: Michal Kreps (University of Warwick (GB))

11:05 Luminosity at LHCb in Run 3

The LHCb detector optimised its performance in Run 1 and 2 by stabilising the instantaneous luminosity during a fill. This is achieved by tuning the distance between the two colliding beams according to the measurement of instantaneous luminosity from hardware-based trigger counters. The upgraded LHCb detector operates at fivefold instantaneous luminosity compared to the previous runs, and it has a fully software-based trigger. Consequently, a new approach to the luminosity measurement is adopted. New counters, with particular attention to maximum stability in time, and a new dedicated detector have been introduced for Run 3. Additionally, in order to verify linearity from calibration to data taking conditions, per-fill emittance scans are performed. In this talk an overview of the newly implemented methods for luminosity measurement is presented. The first results obtained using data collected during 2022 will also be shown, including the ghost charge fraction measurement using the beam-gas imaging technique.

Speaker: Niall Thomas Mchugh (University of Glasgow (GB))

lepton_photon_luminosity_lhcb_nmchugh.pdf

11:20 Luminosity determination in pp collisions at $\sqrt(s)=13$TeV with the ATLAS detector

A precise measurement of the luminosity is a crucial input for many ATLAS physics analyses, and represents the leading uncertainty for W, Z and top cross-section measurements. The final ATLAS luminosity determination for the Run-2 13 TeV dataset is described, based on van der Meer scans during dedicated running periods each year to set the absolute scale, and an extrapolation to physics running conditions using complementary measurements from the ATLAS tracker and calorimeter subsystems. Nearly all aspects of the analysis have been revisited since the preliminary Run-2 calibration, leading to one of the most precise luminosity calibrations at a hadron collider to date.

Speaker: Claudia Seitz (Deutsches Elektronen-Synchrotron (DE))

ATLAS_luminosity_LP2023_clseitz.pdf

11:35 Overview of the ATLAS High-Granularity Timing Detector: project status and results

The increase of the particle flux (pile-up) at the HL-LHC with instantaneous luminosities up to L ≃ 7.5 × 1034 cm−2s −1 will have a severe impact on the ATLAS detector reconstruction and trigger performance. The end-cap and forward region where the liquid Argon calorimeter has coarser granularity and the inner tracker has poorer momentum resolution will be particularly affected. A High Granularity Timing Detector (HGTD) will be installed in front of the LAr endcap calorimeters for pile-up mitigation and luminosity measurement. The HGTD is a novel detector introduced to augment the new all-silicon Inner Tracker in the pseudo-rapidity range from 2.4 to 4.0, adding the capability to measure charged-particle trajectories in time as well as space. Two silicon-sensor double-sided layers will provide precision timing information for minimum-ionising particles with a resolution as good as 30 ps per track in order to assign each particle to the correct vertex. Readout cells have a size of 1.3 mm × 1.3 mm, leading to a highly granular detector with 3.7 million channels. Low Gain Avalanche Detectors (LGAD) technology has been chosen as it provides enough gain to reach the large signal over noise ratio needed. The requirements and overall specifications of the HGTD will be presented as well as the technical design and the project status. The R&D effort carried out to study the sensors, the readout ASIC, and the other components, supported by laboratory and test beam results, will also be presented.

Speaker: Zhijun Liang (Chinese Academy of Sciences (CN))

ATLAS-HGTD-LP2023-v10.pdf

11:50 ATLAS New Small Wheel Performance Studies with first data of LHC Run3

After successfully completing Phase I upgrades during LHC Long Shutdown 2, the ATLAS detector is back in operation with several upgrades implemented. The most important and challenging upgrade is in the Muon Spectrometer, where the two inner forward muon stations have been replaced with the New Small Wheels (NSW) system featuring two entirely new detector technologies: small strip Thin Gap Chambers (sTGC) and the Micromegas (MM). Following the massive build, test and installation work in ATLAS, the two endcap NSW were used in the first collision data period in 2022 participating in the Muon Spectrometer tracking system, at the same time completing the phase of commissioning of this completely new system. A huge effort has gone into the operation of the new data acquisition system, as well as the implementation of a new processing chain within the muon software framework. The new detectors are fully integrated into the software. Tracking is performed with full consideration of the absolute alignment of each individual detector module by the ATLAS Muon Spectrometer optical alignment system. All the deviations from the nominal geometry of all the constituent elements of each sTGC and MM module are accounted for through the modeling of the real chamber geometry reconstructed from the information of the construction databases. After an overview of the software implementation and the strategies adopted for the simulations and reconstruction, the studies on the performance of the NSW system from the first months of 2022 RUN3 data taking will be reported.

Speaker: Tairan Xu (University of Michigan (US))

NSW_ATLAS_LP2023.pdf

12:05 The CMS tracker upgrade for HL-LHC

The LHC machine is planning an upgrade program which will smoothly bring the luminosity to about $5-7.5\times10^{34}$Hz cm$^{-2}$, to possibly reach an integrated luminosity of $3000-4000\;$fb$^{-1}$ over about a decade. This High Luminosity LHC scenario, HL-LHC, starting in 2029,

In order to fully exploit the delivered luminosity and to cope with the demanding operating conditions, the whole silicon tracking system will have to be replaced and substantially upgraded before starting the HL-LHC, a plan known as CMS Phase-2 upgrade.

Both the CMS inner tracker (IT) detector and the outer tracker (OT) will be replaced and the new detector will feature increased radiation hardness, higher granularity and capability to handle larger data rate. While the IT electronics will handle a longer trigger latency, a key upgrade of the OT detector is to incorporate the identification of charged particle trajectories in the hardware-based (L1) trigger system. A 40 MHz silicon-based track trigger on the scale of the CMS detector has never before been built.

The design choices for the Tracker upgrades are discussed along with some highlights on technological approaches and latest results on the system testing of the prototypes. Recent L1 track trigger developments will be presented as well.

Speaker: Alessandro Rossi (Universita e INFN, Perugia (IT))

CMSTrackerUpgrade_LeptonPhoton23_RossiA_v2.pdf

12:20 Level-1 Track Finding at CMS for the HL-LHC

The success of the CMS physics program at the HL-LHC requires maintaining sufficiently low trigger thresholds to select processes at the electroweak scale. With an average expected 200 pileup interactions, critical to achieve this goal while maintaining manageable trigger rates is in the inclusion of tracking information in the Level-1 (L1) trigger. A 40 MHz silicon-based track trigger on the scale of the CMS detector has never before been built; it is a novel handle, which in addition to maintaining trigger rates can enable entirely new physics studies.

The main challenges of reconstructing tracks in the L1 trigger are the large data throughput at 40 MHz and the need for a trigger decision within 12.5 µs. To address these challenges, the CMS outer tracker for HL-LHC uses modules with closely-spaced silicon sensors to read out only the hits compatible with charged particles above 2-3 GeV ("stubs"). These are used in the back-end L1 track finding system, implemented using commercially available FPGA technology. The ever-increasing capability of modern FPGAs combined with their programming flexibility are ideal for implementing fast track finding algorithms. The proposed reconstruction algorithm forms track seeds ("tracklets") from pairs of stubs in adjacent layers of the outer tracker. These seeds provide roads where consistent stubs are included to form track candidates. Track candidates sharing multiple stubs are combined prior to being fitted. A Kalman Filter track fitting algorithm is employed to identify the final track candidates and determine the track parameters. The system is divided into nine sectors in the r-phi plane, and time-multiplexed by a factor of 18, so that each event in one sector is processed by a dedicated track finding board.

This presentation will discuss the CMS L1 track finding algorithm and its implementation, present simulation studies of estimated performance, and show recent results from a scalable system demonstrator based on prototype hardware.

Speaker: Dr Rui Zou (Cornell University (US))

TrackFinder_LP2023_RZou_v1.pdf

11:05 → 12:50 Low energy: Room C

Convener: Jacinda Ginges

11:05 Measurement of the anomalous spin precession frequency $\omega_a$ in the Muon $g-2$ experiment at Fermilab

The muon anomaly, $a_\mu=(g_{\mu}-2)/2$, is a low-energy observable which can be both measured and computed to high precision, making it a sensitive test of the Standard Model (SM) and a probe for new physics. The current discrepancy between the experimental value and the Standard Model calculation from the Muon $g-2$ Theory Initiative [T. Aoyama et al. - Phys. Rep. 887, 1 (2020)] is $a_{\mu}^{exp}-a_{\mu}^{SM}=(251\pm59)\cdot10^{-11}$, with a significance of $4.2\,\sigma$.
The Fermilab E989 experiment aims, with the full statistical power, to measure $a_{\mu}$ with a precision of $140\,$parts per billion (ppb), a four-fold improvement with respect to the previous measurement at the Brookhaven E821 experiment (1997-2001).
In April 2021 the FNAL E989 collaboration published their first result, based on the first year of data taking (2018 campaign) [B. Abi et al. (Muon $g-2$ Collaboration), Phys. Rev. Lett. 126, 141801 (2021)], and this year a new result is expected to be published, based on the datasets collected during Run-2 and Run-3 (2019 and 2020 campaigns).
A $3.1$-GeV spin-polarized beam of muons is injected into a storage ring of $14\,$m of diameter, in the presence of a $1.45\,$T magnetic field. The anomaly $a_\mu$ can be extracted by accurately measuring the anomalous muon spin precession frequency, $\omega_a$, and the magnetic field environment using Nuclear Magnetic Resonance techniques. The measurement of $\omega_a$ is based on the arrival time distribution of decay positrons in the high-energy tail of the spectrum, observed by $24$ electromagnetic calorimeters that are placed around the inner circumference of the storage ring. The histogram of positron counts is fitted with a function that takes into account detector and beam dynamics effects.
This talk will present details about the improvements and upgrades to the positron reconstruction and to the $\omega_a$ analysis since the 2021 results, and it will describe the final statistical and systematic sources of uncertainty in the new result.

Speaker: Mr Lorenzo Cotrozzi (on behalf of the Muon g-2 collaboration) (University of Pisa and INFN Pisa)

LeptonPhoton_2023_Cotrozzi.pdf

11:20 Low-energy excess in search for dark matter with DAMIC-SNOLAB

In 2020, the DAMIC collaboration reported a 3 Sigma excess while searching for low-mass WIMPs using silicon CCD detectors with an analysis energy threshold of 50 eVee that were situated in SNOLAB. Since then, the experiment was upgraded to make use of skipper-CCD readout, which allows single-electron energy resolution. With this upgrade, the energy threshold could be reduced to 23 eVee, improving signal efficiency as well as discrimination between surface and bulk events. The new experimental result from DAMIC@SNOLAB yields a result consistent with the previous, but with a larger significance of 5 Sigma. This presentation will explain the newest DAMIC result in the context of previous results, as well as future prospects.

Speaker: Prof. Ben Kilminster (University of Zurich (CH))

Kilminster-DAMIC-LP2023.pdf

11:35 Status of the Large Enriched Germanium Experiment for Neutrinoless $\beta\beta$ Decay (LEGEND)

The Majorana nature of the neutrino, i.e., whether it is its own antiparticle, remains an open problem in modern physics. The observation of the hypothesized second order weak interaction, Neutrinoless Double Beta Decay (0$\nu\beta\beta$), is the only known experimental signature which would conclusively establish the Majorana nature of neutrinos. It would also demonstrate lepton number violation and could provide insight into the absolute neutrino mass scale. Previous experimental searches for 0$\nu\beta\beta$ in $^{76}Ge$ achieved the lowest background indexes and energy resolutions of all 0$\nu\beta\beta$ searches. Combining the technologies and techniques from the GERDA and Majorana Demonstrator experiments, the next generation tonne-scale germanium experiment LEGEND-1000 is projected to have a background index of $10^{-5}$ counts/(keV.kg.yr) and sensitivity to a decay half-life beyond $10^{28}$ yr. In phase 1, LEGEND-200 will operate 200 kg of enriched detectors in the upgraded GERDA cryostat at LNGS, Italy. In a planned phase 2, LEGEND-1000 will operate 1000 kg of enriched detectors at a site that is yet to be finalized. Currently, the first phase of the experiment LEGEND-200 is being commissioned at LNGS, with 142 kg of germanium detectors acquiring data. In this talk, the status and science outlook of LEGEND will be presented, on behalf of the collaboration.

Speaker: Dr Aparajita Mazumdar (Los Alamos National Laboratory)

2023-07-05-Mazumdar-LeptonPhoton2023-Melbourne-v3.pdf

11:50 Search for sub-millicharged particles at J-PARC

Electric charge quantization is a long-standing question in particle physics. While fractionally charged particles (millicharged particles hereafter) have typically been thought to preclude the possibility of Grand Unified Theories (GUTs), well-motivated dark-sector models have been proposed to predict the existence of millicharged particles while preserving the possibility for unification. Such models can contain a rich internal structure, providing candidate particles for dark matter. A number of experiments have searched for millicharged particles ($\chi$s), but in the parameter space of the charge ($𝑄$) and mass ($m_\chi$), the region of $𝑚_\chi>0.1$ GeV/$\rm{c}^2$ and $𝑄<10^{−3}$𝑒 is largely unexplored.

SUB-Millicharge ExperimenT (SUBMET) has been proposed to search for sub-millicharged particles using 30 GeV proton fixed-target collisions at J-PARC. The detector is composed of two layers of stacked scintillator bars and PMTs, and is proposed to be installed 280 m from the target. The main background is expected to be a random coincidence between the two layers due to dark counts in PMTs and the radiation from the surrounding materials, which can be reduced significantly using the timing of the proton beam. With $\rm{N}_{\rm{POT}}=5\times 10^{21}$, the experiment provides sensitivity to $\chi$s with the charge down to $8\times 10^{−5}𝑒$ in $𝑚_\chi<0.2$ GeV/$\rm{c}^2$ and $10^{−3}𝑒$ in $𝑚_\chi>1.6$ GeV/$\rm{c}^2$. This is the regime largely uncovered by the previous experiments.

Speaker: Mr Hoyong Jeong (Korea University)

LP_2023_HY.pdf

12:05 The MEGII experiment and exotic searches

The MEG experiment searches for the μ+ → e+ γ decay and has set the most stringent upper limit on its branching ratio B(μ+ → e+ γ) < 4.2 10-13 at 90% C.L. It is a factor 30 improvement over the previous limit set by the MEGA experiment (B(μ+ → e+ γ)< 1.2 10-11 at 90% C.L.) and also the strongest bound on any forbidden particle decay.
The compelling physics motivation to further explore the μ+ → e+ γ decay has led the collaboration to decide upon an upgrade of the experiment, with the aim to improve the sensitivity by at least one order of magnitude. The MEG upgrade (MEGII) has been approved at PSI and by the institutions of international collaboration and is now underway with its physics run, which followed the full engineering run scheduled and accomplished during 2020-21.
MEGII started the data-taking period in 2021. 2022 represented the world record physics run in terms of the collected data sample. MEGII is expected to continue data taking for the following years until the full statistics is achieved. More exotics searches are also considered and carried out with the MEGII apparatus.
The current status of MEGII, as well as more exotic searches performed with the MEGII apparatus, will be presented.

Speaker: Angela Papa

MEGII_LP2023_AP.pdf

12:20 Effect of Ultralight Dark Matter on g-2 of the Electron

If dark matter is ultralight, the number density of dark matter is very high and the techniques of zero-temperature field theory are no longer valid. The dark matter number density modifies the vacuum giving it a non-negligible particle occupation number. For fermionic dark matter, this occupation number can be no larger than one. However, in the case of bosons the occupation number is unbounded. If there is a large occupation number, the Bose enhancement needs to be taken into consideration for any process involving particles which interact with the dark matter. Because the occupation number scales inversely with the dark matter mass, this effect is most prominent for ultralight dark matter. In fact, the Bose enhancement effect from the background is so significant for ultralight dark matter that, if dark matter is a dark photon, the correction to the anomalous magnetic moment is larger than experimental uncertainties for a mixing parameter of order $10^{-16}$ and a dark photon mass of order $10^{-20}$ eV. Furthermore, the constraint on the mixing parameter scales linearly with the dark photon mass and so new significant constraints can be placed on the dark matter mass all the way up to $10^{-14}$ eV. Future experiments measuring $g-2$ will probe even smaller gauge mixing parameters.

Speaker: Jason Evans

UltraLightDarkMattergminus2short.pdf

11:05 → 12:50 Neutrino: Room E

Convener: Dr. Rukmani Mohanta

11:20 NA65(DsTau): study of tau neutrino production in p-A interactions

The DsTau experiment at CERN-SPS has been proposed to measure an inclusive differential cross-section of a Ds production with a consecutive decay to tau lepton in p-A interactions. A precise measurement of the tau neutrino cross section would enable a search for new physics effects such as testing the Lepton Universality (LU) of Standard Model in neutrino interactions. The detector is based on nuclear emulsion providing a sub-micron spatial resolution for the detection of short length and small “kink” decays. Therefore, it is very suitable to search for peculiar decay topologies (“double kink”) of Ds→τ→X. In 2022, the second physics run of the experiment was performed successfully. In this talk we discuss the physics potential of the experiment and present the analysis result of the pilot run data and the near-future plans.

Speaker: Toranosuke Okumura (Chiba University (JP))

Lepton_Photon_DsTau.pptx

11:35 MicroBooNE's tests of the MiniBooNE anomalous low-energy excess

MicroBooNE is an 85 tonne active mass liquid argon time projection chamber that uses the same mainly-muon-neutrino beamline as the MiniBooNE experiment. One of the main motivations when the experiment was proposed was to investigate the “low energy excess” (LEE) of electromagnetic (EM) shower events observed by the MiniBooNE experiment, which could not be explained by standard three-flavor neutrino oscillation models. MicroBooNE has released the first results of this measurement, searching for an excess of either electrons from charged-current electron neutrino interactions or photons from NC 𝚫 decays. In this talk I will present these first results, and also the interpretation of these results in the context of neutrino oscillation models with an additional sterile state which induce both appearance and disappearance of electron neutrinos. I will finish the talk with an overview of ongoing LEE analyses in MicroBooNE, including an inclusive single photon-like EM shower selection, and searches for other BSM explanations of the MiniBooNE anomaly.

Speaker: Erin Yandel

MicroBooNE LEE Lepton Photon.pdf

11:50 Latest results from Daya Bay with full dataset

The Daya Bay Reactor Neutrino Experiment was designed with the primary goal of precisely measuring the neutrino mixing parameter, $\theta_{13}$. Eight identically-designed gadolinium-doped liquid scintillator detectors installed in three underground experimental halls measure the reactor antineutrinos from six nuclear reactors at different distances. Until its shutdown at the end of 2020, Daya Bay experiment has acquired nearly 6 million inverse beta decay candidates with neutron captured on gadolinium. In this talk, the latest neutrino oscillation analysis results based on full data will be presented. The resulting oscillation parameters are $\rm{sin}^{2}2\theta_{13} = 0.0851 \pm 0.0024$, $\Delta m^{2}_{32} = (2.466 \pm 0.060) \times 10^{−3} \rm{eV}^2$ for the normal mass ordering or $\Delta m^{2}_{32} = −(2.571 \pm 0.060) \times 10^{−3} \rm{eV}^2$ for the inverted mass ordering, which are the most precise measurement of $\theta_{13}$ and $\Delta m^{2}_{32}$ so far. Moreover, latest results on other topics such as the search of sterile neutrino and the measurement of absolute flux and spectrum of reactor antineutrino are included as well.

Speaker: Zhiyuan Chen (Institute of High Energy Physics, Chinese Academy of Sciences)

LP2023_DayaBay_July19.pdf

12:05 Neutrino Oscillations at the NOvA experiment

NOvA is a long-baseline neutrino oscillation experiment based at the Fermi National Accelerator Laboratory, USA. Utilizing two functionally-identical liquid scintillator tracking calorimeters placed 810 km apart, NOvA observes the appearance of electron (anti)neutrinos and the disappearance of muon (anti)neutrinos in the muon (anti)neutrino-dominated NuMI beam. By observing these (anti)neutrino oscillations, NOvA is probing several key questions in the physics of neutrino oscillations including the neutrino mass ordering, leptonic CP violation phase $\delta_{CP}$, the larger neutrino mass splitting $\Delta m^2_{32}$, and the mixing angle $\theta_{23}$. Up-to-date neutrino oscillation results from NOvA will be presented.

Speaker: Dr Liudmila Kolupaeva (JINR)

nova.pdf

12:20 The Hyper-Kamiokande experiment: design, status of construction and physics goals

Hyper-Kamiokande (HK) is the next generation water Cherenkov detector being constructed in Japan, following in the footsteps of the very successful Kamiokande, Super-Kamiokande and T2K experiments. The Hyper-Kamiokande far detector (260 kton) is planned to be instrumented with 20,000 50 cm diameter photomultiplier tubes (PMT) and about 2,000 multi-PMT optical sensors (each containing 19 7.6 cm PMTs) looking inwards at the detector and 7,200 7.6 cm diameter PMTs looking outwards to veto cosmic radiation and other backgrounds. The design and construction of the detector is at an advanced stage. Hyper-Kamiokande is expected to be commissioned in 2027. The experiment will also count with an Intermediate Water Cherenkov Detector (IWCD) at a site approximately 900 m from the target used to produce neutrino beams at the J-PARC accelerator facility, while the Hyper-Kamiokande far detector is located 295 km away. The main physics goals of the experiment are to significantly improve the precision of neutrino oscillation measurements using the upgraded J-PARC neutrino beam, including the potential discovery of CP violation in the neutrino sector of the Standard Model, measurements of neutrinos from astrophysical sources, such as cosmic rays, solar neutrinos and neutrinos originating from supernovae, and a world-leading search for proton decay.

In this talk, I will describe the design of the Hyper-Kamiokande far and intermediate water Cherenkov detectors, the status of their construction and the expected physics capabilities of the experiment.

Speaker: Prof. Paul Soler Jermyn (University of Glasgow (GB))

Lepton_Photon_2023_HK_Soler.pdf

Thursday 20 July

09:00 → 10:10 Low energy: Committee

Convener: Ulrik Egede (Monash University (AU))

09:00 IUPAP C11 report

Speaker: Florencia Canelli (University of Zurich (CH))

C11-2023 - summary.pdf

09:15 ICFA report

Speaker: Stuart Henderson

ICFA Status Lepton Photon July 2023 v2.pptx

09:30 Panel debate: Mental health in Particle Physics

Speakers: Harish Potti (University of Adelaide (AU)), Kim Cornish (Monash University), Dr Moon Moon Devi (Tezpur University, India)

Harish's_Speech

Monash Thrive portal

10:10 → 10:40 Low energy

Convener: Ulrik Egede (Monash University (AU))

10:10 Muon (g-2) SM vs experiment

The anomalous magnetic moment of muon has been used as an indication of physics beyond the Standard Model. Fermilab Muon g-2 experiment has published the most precise measurement of the anomalous magnetic moment of muon with an uncertainty of 460 part-per-billion which showed 4.2 sigma discrepancy between the experiment average and the 2020 g-2 Theory Initiative Standard Model prediction. This talk will show the recent results from the Fermilab Muon g-2 experiment while also briefly cover the status of the Standard Model prediction on calculating the anomalous magnetic moment of muon.

Speaker: Esra Barlas Yucel (University of Illinois at Urbana Champaign)

LeptonPhoton_Muon_g-2_Exp_and_SM.pdf

10:40 → 11:10 Morning break

11:10 → 12:40 Detectors and facilities

Convener: Petar Kevin Rados (DESY)

11:10 Operation, challenges and future developments of SuperKEKB

Speaker: Dr Tetsuo Abe (High Energy Accelerator Research Organization (KEK))

LP2023_SuperKEKB_v3.pdf

LP2023_SuperKEKB_v3.pptx

11:40 Machine learning for low-latency inference

Speaker: Dylan Sheldon Rankin (University of Pennsylvania (US))

lp_fastml_dsr_17jul23.pdf

12:10 Upgrades of the experiments for the High luminosity phase of LHC

Following an intense period of R&D and engineering of technical solutions, ATLAS and CMS are entering production of their upgrades for the High Luminosity LHC. This presentation will highlight the major experimental challenges and the recent progress in preparation of the new detectors. While ATLAS and CMS will continue to be exposed to the highest luminosities and subsequent collision pile-up and data flows, Alice and LHCb are proposing new upgrades during the future Long Shutdown LS3 and LS4 with specific performance requirements. An overview of these new projects will be presented; together with a perspective on related R&Ds considered in the framework of the Detector Research and Development (DRD) international collaborations being formed at CERN.

Speaker: Didier Claude Contardo (Centre National de la Recherche Scientifique (FR))

LP2023_DC.20072023.pdf

LP2023_DC.20072023.pdf

LP2023_DC.20072023.pptx

12:40 → 13:40 Lunch

13:58 → 14:30 Detectors and facilities

Convener: Florencia Canelli (University of Zurich (CH))

13:58 Monash Uni on Friday

Speaker: Ulrik Egede (Monash University (AU))

LP23Thursday.pdf

14:00 Belle II and LHCb Upgrade I performance

Speakers: Petar Kevin Rados, Petar Kevin Rados (DESY)

Belle2_LHCbU1_Perf_FV_v1.pdf

14:30 → 16:00 Dark Matter

Convener: Dr Irene Bolognino (The University of Adelaide)

14:30 The SABRE experiment

Speaker: Elisabetta Barberio

SABRE_LP_FV.pdf

15:00 Theoretical perspective on Dark Matter searches

Speaker: Prof. Nicole Bell (The University of Melbourne)

Lepton_Photon_2023_Bell.pdf

15:30 Liquid Xenon Dark Matter searches

Liquid Xenon Time Projection Chambers are the leading technology for WIMP Dark Matter searches. The current second generation detectors, LZ, PandaX-4T, and XENONnT, are taking data and producing results - their status and their prospects will be reviewed.
At the same time the XLZD consortium is preparing for a third generation detector in this tradition, which will either follow up on any signal seen in the current generation, or carry on the search - towards the neutrino fog. A brief outline of the status and challenges to be met by the consortium will conclude the review.

Speaker: Kai Martens (The University of Tokyo)

16:00 → 16:30 Afternoon break

18:00 → 19:00 Welcome, closing and society: Public talk

Convener: Ulrik Egede (Monash University (AU))

18:00 Lepton Photon public talk

Please remember that you have to register separately for this event. It is free of charge for conference attendees.

Speakers: Prof. Alan Duffy (Swinburne University of Technology), Dr Suzie Sheehy (University of Oxford and University of Melbourne)

Public talk information

19:30 → 22:00 Conference dinner

Friday 21 July

08:30 → 09:15 Train to Monash University

Remember that the session today will take place at Monash University. You can take train from either Southern Cross or Flinders Street stations. See Google link for directions. You can use the MyKi card that you were given at registration for checking in and out of stations. At Southern Cross, the train will leave from Platform 12, and at Flinders Street from Platform 6. There will be Monash students wearing blue T-shirts at the stations to help you in the right direction. Remember to get off the train at Huntingdale station.

09:30 → 10:30 Collider Precision

Convener: Prof. Peter Skands (Monash University (AU))

09:30 Rare electroweak production measurements

During run 2 of the LHC the ATLAS and CMS experiments each collected nearly 140 inverse fb of pp collisions at sqrt(s) = 13 TeV. This data sample, in combination with advanced experimental techniques, enables searches for rare production processes that were so far inaccessible at previous experiments. Results will be presented of the searches for rare processes predicted by the Standard Model involving the heaviest known elementary particles. In the last year ATLAS and CMS have observed several new tri-boson production processes, completed the list of associated top-quark production processes with gauge bosons and observed four-top-quark production with a statistical significance well over 5 sigma. The measurements of production rates and differential distributions for these rare processes provide direct bounds on several Standard Model couplings.

Speaker: Marcel Vos (IFIC Valencia (ES))

LHCRareProcesses.pdf

PDF for ACROBAT reader

10:00 Future challenges for event generators

Speaker: Davide Napoletano (Universita & INFN, Milano-Bicocca (IT))

talk.pdf

10:30 → 11:00 Morning break

11:00 → 12:00 Astrophysics

Convener: Prof. Nicole Bell (The University of Melbourne)

11:00 Probing ultralight bosons with black holes and gravitational waves

Ultralight boson particles, if they exist as theorized, could form clouds around rapidly rotating black holes through the phenomenon called superradiance. Such clouds are expected to emit long-lasting, quasimonochromatic gravitational radiation. Searching for gravitational waves emitted by boson clouds around black holes provides a new cosmic approach to interrogating the existence of ultralight bosons that are difficult to probe with conventional lab experiments. In this talk, I will provide a theoretical overview of the phenomenon, describe the gravitational wave signatures, and discuss the search prospects targeting stellar mass black holes.

Speaker: Ling Sun (Australian National University)

lepton_photon_2023.pdf

11:30 Particle physics with cosmic neutrinos

The IceCube Neutrino Observatory at the South Pole has been fully operational for over a decade. With a cubic kilometre of deep ice as the detection volume, the detector has seen thousands of astrophysical neutrinos from across the sky – with the first steady point source (NGC1068) recently discovered. In this talk we will discuss what we have learned about the astrophysical origins of these neutrinos, as well as give results in various areas of particle physics that are accessible with these and the even greater flux of background atmospheric neutrinos.

Speaker: Gary Hill (University of Adelaide)

12:00 → 12:30 Flavour

Convener: Anjan Giri

12:00 Semileptonic b-hadron decays

This talk will cover the most recent results of semileptonic b-hadron decays from the Belle II and LHCb experiments and their implications to potential new physics beyond the standard model.

Speaker: Chunhui Chen (Iowa State University (US))

LP2023-ChunhuChen.pdf

12:30 → 13:30 Lunch

13:30 → 14:30 Flavour

Convener: Anjan Giri

13:30 CP violation in heavy flavour decays

The recent highlights in charge-parity violation in heavy flavour decays from the LHCb, Belle II and BESIII experiments will be presented. These include updated measurements of sin2beta, Bs meson mixing phase phi_s, CP violation in Bs-->phi phi, CKM angle gamma by LHCb using Run 2 data, combined Belle and Belle II measurement of gamma, new results on sin2beta, Vub and Vcb by Belle II, and improved measurement of strong phase parameters of D0 decays by BESIII.

Speaker: Yuehong Xie (Central China Normal University CCNU (CN))

CPVB-xie.pdf

14:00 Heavy flavour production

This talk will provide an overview of recent results related to the production of heavy flavour hadrons at the LHC experiments.

Speaker: Victor Jose Gaston Feuillard (Heidelberg University (DE))

HFProduction_VictorFeuillard_LeptonPhoton2023Talk_v5.pdf

14:30 → 15:30 Welcome, closing and society

Convener: Ulrik Egede (Monash University (AU))

14:30 Ireland @ CERN

Speaker: Dr Venus Keus (Dublin Institute for Advanced Studies (DIAS))

VKeus_CATCH22+2.pdf

14:35 Poster prizes

Prizes will be awarded for best posters

Speakers: Bruce Donald Yabsley (University of Sydney (AU)), Prof. Peter Skands (Monash University (AU))

lp23posters.pdf

14:45 Close of conference

Speaker: Ulrik Egede (Monash University (AU))

LP23Friday.pdf