Fysikdagarna 2022

15 Jun 2022, 09:00 → 17 Jun 2022, 15:00 Europe/Stockholm

Joakim Cederkall (Lund University (SE)), Malin Sjödahl, Per Eng-Johnsson (Lund University), Peter Christiansen (Lund University (SE)), Susanne Tegler, Tomas Brage, Torbjörn Lundberg, Urban Eriksson (Lund University)

The annual conference of the Swedish Physical Society, Fysikdagarna, was held in Lund 15–17 June 2022 with all the plenary events taking place at AF-borgen. The conference consisted of parallel sessions organized by the individual sections (Wednesday afternoon and Friday morning), a plenary day with a conference dinner (Thursday), a plenary poster session (Wednesday evening) and the open annual meeting of the Swedish Physical Society (Friday before lunch). Check the timetable for an easy overview. The final program can also be downloaded as a pdf here: link.

The theme of the 2022 meeting was Swedish accelerator-based science with plenary contributions on CERN, FAIR, MAX IV, and ESS.

Plenary speakers:

• Achim Schwenk (Technical University of Darmstadt)

• Andreas Schreyer (Science Director at ESS)

• Eugenia Etkina (Rutgers University, 2014 Millikan Medal)

• Martin Bech (Lund University)
• Meytal Eran-Jona (Head of Diversity and Inclusion Office, Weizmann Institute of Science, WIS) and Yosef Nir (WIS)
• Sara Blomberg (Lund University)
• Sara Strandberg (Stockholm University, Göran Gustafsson Prize 2018)
• Svante Jonsell (Stockholm University)
• Stephen Molloy (Head of Accelerator Operations at MAX IV)
• Troels Petersen (NBI)

The winner of the best poster award was Emma Campillo (Lund University).

 

Organisers: Anna Arnadottir, Joakim Cederkäll, Malin Sjödahl, Per Eng-Johnsson, Peter Christiansen (chair), Susanne Tegler, Tomas Brage, Torbjörn Lundberg, Torsten Åkesson, and Urban Eriksson.

   

Credits: the Lund graphics used in the conference logo was originally made by Eamonn Maguire from Antarctic Design for the LHCP 2016 conference.

poster2022-en.pdf

poster2022.pdf

program.pdf

Wednesday 15 June

09:00 → 12:00 Sektionen för elementarpartikel och astropartikelfysik: AF Borgen: Nya Fest

09:00 Particle days: Welcome and Introduction

Fysikdagarna.pdf

09:15 ATLAS experiment: Overview of activities at KTH

This contribution will present the current activities in the KTH team working on the ATLAS experiment at the LHC. An overview of topics ranging from luminosity studies and ongoing Run-2 analysis topics to HL-LHC upgrade work will be discussed.

Speaker: Christian Ohm (KTH Royal Institute of Technology (SE))

ATLASatKTH.pdf

09:30 Search for a supersymmetric long-lived particle at the ATLAS experiment

A search for a long-lived supersymmetric particle at ATLAS in multi-jet events with a displaced vertex. The talk will focus on event selection, suppression of background through means of vetoing certain detector regions as well as the final limits set by the search.

Speaker: Karl Filip Backman (Stockholm University (SE))

Partikeldagarna_FilipBackman.pdf

09:45 Search for Higgs-like scalar particles in the $bb \gamma \gamma$ final state with the ATLAS experiment.

We develop a new class of experimental search for new Higgs-like spin-0 particles with the ATLAS experiment at LHC. We focus on the essentially unexplored asymmetric Higgs decay $X \rightarrow SH$, where $X$ and $S$ denote two BSM spin-0 Higgs-like neutral particles and $X$ is the heavier of the two ($m_X > m_S$). $H$ denotes the already experimentally known Higgs boson with a mass of $m_H = 125$ GeV. This type of LHC signature arises in models that predict primordial Gravitational Waves (GW) and are able explain the baryon- antibaryon asymmetry of the universe via Strong First Order Electroweak Phase Transition which generates primordial GW in the process. In this talk we present the construction of a search for $X \rightarrow SH$ in the two photon, two b-jet final states and projected sensitivities with Run-2 and Run-3 data.

Speaker: Stefio Yosse Andrean (Stockholm University (SE))

yosse_partikeldagarna2022.pdf

10:00 Break

10:30 Effective Field Theory interpretations of Higgs boson pair production searches in ATLAS

After the discovery of the Higgs boson in 2012, an important test of the electroweak symmetry breaking would be to establish evidence of the Higgs boson self-coupling, which can be achieved through a measurement of Higgs boson pair production. In the Standard Model (SM), di-Higgs events are dominantly produced in gluon-gluon fusion processes at the LHC, e.g. involving the Yukawa coupling to top quarks (top-quark loops) or via the Higgs boson self-coupling. These two production modes interfere destructively, which leads to a very small di-Higgs production cross-section. However, deviations in couplings of the Higgs boson from SM expectation as well as new vertices in Effective Field Theories (EFT) could lead to a significant enhancement of the di-Higgs production rate. A re-interpretation of the search for non-resonant Higgs boson pair production in terms of Higgs EFT (HEFT) benchmark models is presented. Upper limits on the HH production cross-section are set for seven HEFT benchmark models and exclusion limits are set on two HEFT coupling parameters associated with the couplings of a Higgs boson pair with two gluons, c_{gghh}, and with a top-quark pair, c_{tthh}.

Speaker: Christina Dimitriadi (University of Bonn (DE))

partikeldagarna_2022_cdimitriadi.pdf

10:45 Status and Prospects of Light Dark Matter eXperiment

An elegant explanation for the origin and observed abundance of dark matter in the Universe is the thermal freeze-out mechanism. Within this mechanism, possible masses for dark matter particle candidates are restricted approximately to the MeV - TeV range. The GeV-TeV mass range is being explored intensely by a variety of experiments searching for Weakly Interacting Massive Particles. The sub-GeV region occurs naturally in Hidden Sector dark matter models, but has been tested much less by experiments to date. Exploring this mass range is imperative as part of a comprehensive Dark Matter search programme, but requires new experimental approaches.

The freeze-out mechanism assumes a non-gravitational interaction between dark and ordinary matter, which necessarily implies a production mechanism for dark matter at accelerator experiments. Recent advancements in particle accelerators and detectors in combination with software developments like machine learning techniques open new possibilities to observe such processes.

The planned Light Dark Matter eXperiment (LDMX) is an electron-beam, fixed- target experiment that exploits these developments, enabling us to observe processes orders of magnitudes rarer than what is detectable today. The key to this is a multi-GeV beam providing a few electrons 46-million times per second, and a detector that monitors how each individual electron interacts in the target — for up to $10^{16}$ electrons. First beam for commissioning the experiment is expected in early 2024 at SLAC, Stanford, marking the starting point of a first data taking period of about one and a half years. A second phase with higher beam-energy and -intensity is foreseen soon thereafter.

This presentation will give an overview of the theoretical motivation and the different components of the LDMX detector concept, as well as the main experimental challenges and how they are addressed. It will further discuss projected sensitivities and possible future upgrades towards covering a large portion of the viable phase-space for sub-GeV thermal relic dark matter and other models.

Speaker: Ruth Pottgen (Lund University (SE))

LDMX_FD_June2022.pdf

11:00 The SMARTHEP International Training Network

Growing amounts of research data require new computing solutions to manage increased data storage, utilisation, and analysis capabilities. The EU-funded SMARTHEP project, where Lund is one of the founding participants, will break from the traditional paradigm of ‘first collect data, then analyse it’ and move towards real-time analysis (RTA) where data collection and analysis become synonymous, so that unprocessed information that would be expensive to store can be discarded. As a consortium formed by academic and industrial partners on scientific, technological, and entrepreneurship aspects of RTA, the SMARTHEP project will train a new generation of inter-sector researchers and give them the tools to process large datasets in real-time, aided by machine learning and hybrid computing architectures. In this contribution we will outline how the network has started, its plans and possible ways to collaborate with other Swedish institutes.

Speaker: Caterina Doglioni (University of Manchester (GB))

20220615_Doglioni_Fysikdagarna_SMARTHEP.pdf

11:15 Differentiable Programming for High-Energy Physics

Abstract: Machine learning methods are now ubiquitous in physics, but often target objectives that are one or two steps removed from our physics goals. A prominent example of this is the discrimination between signal and background processes, which doesn’t account for the presence of systematic uncertainties — something crucial for the calculation of quantities such as the discovery significance and upper limits.

To combat this, we show that physics analysis workflows can be optimised in an end-to-end fashion, including the treatment of nuisance parameters that model systematic uncertainties, provided that the workflow is differentiable. By leveraging automatic differentiation and surrogates for non-differentiable operations, we’ve made this possible for the first time, and demonstrate its use in a proof-of-concept scenario.

This talk will motivate the use of end-to-end optimisation as described above, cover the techniques that make it possible, and show recent developments in a high-energy physics context. Future directions that aim to scale and apply these methods will also be highlighted.

Speaker: Mr Nathan Daniel Simpson (Lund University (SE))

Google Slides

11:30 IPPOG/outreach

Speakers: Jonas Strandberg (KTH Royal Institute of Technology (SE)), Sara Strandberg (Stockholm University (SE))

IPPOGReport.pdf

11:45 High-School/outreach

Speaker: Kristian Strid (St Petri)

SVENSKA FYSIKDAGARNA I LUND-StPetri.pdf

12:30 → 17:00 Parallel session: The default times are 13:00-17:00

12:30 → 17:00 Sektionen för kärnfysik: AF Borgen, Kerstins rum

Convener: Joakim Cederkall (Lund University (SE))

12:30 Isospin-symmetry breaking in nuclei and applications

Isospin symmetry is known to be a very useful, but approximate symmetry of atomic nuclei, violated by electromagnetic interactions between nucleons. Modern experiments exploring structure and decay of neutron-deficient nuclei and nuclei along N=Z line continue to bring new information on various features related to isospin-symmetry breaking. In this talk we will review the current status of the isospin non-conserving shell model and its capacities to describe isospin-symmetry breaking using phenomenological or microscopic effective interactions. We will point out possible limitations of purely theoretical determination of isospin mixing and needs for experimental constraints, as well as we discuss beta-delayed proton-gamma emission as a novel tool to probe isospin impurities. Important consequences will be stressed for calculation of astrophysical radiative proton capture reactions. Finally, we will present recent progress in theoretical computations of isospin-symmetry breaking corrections for superallowed beta decay, crucial for the Standard Model tests.

Speaker: Nadezda Smirnova (Laboratoire de Physique des Deux Infinis Bordeaux (LP2IB))

13:00 Recent results from the R3B experiment

By studying the neutron skin thickness across the Sn isotopic chain, one can gain a rich insight into the slope of the density dependence of the symmetry energy. A novel method using the total neutron-removal cross section (𝜎𝛥N) has been shown to be highly sensitive to the slope, with a 1% change in 𝜎𝛥N corresponding to a variation of L=±5 MeV. Experiments that have been performed at GSI at 400<E/A (MeV/nuc)<900 with
120,124,128,132,134Sn projectiles on p and 12C
targets will be discussed in this presentation.

Speaker: Dr Andrea Jedele (Technical university Darmstadt)

13:30 Bayesian inference and predictions in the few-nucleon sector

Effective field theories (EFTs) of the strong nuclear interaction is imbued with uncertainty stemming from, e.g., experimental errors and truncation of the EFT expansion. Theoretical predictions of nuclear observables should thus be considered---and presented---as probability density functions (PDFs) rather than scalar values. Working in a Bayesian framework, we have inferred PDFs for the EFT model parameters from observables in the few-nucleon sector by combining efficient computational methods with advanced sampling techniques and prior knowledge. This enables us to sample the PDFs for predictions of nuclear observables. We also learn that the predictions are precise enough to pick up the small isospin dependency of the nucleon-nucleon interaction. The talk will also cover ongoing work to condition the inference on data in heavier-mass nuclei using highly efficient and accurate emulators.

Speaker: Isak Svensson

13:50 Posterior predictive distributions of nucleon-deuteron scattering observables

Nucleon-deuteron (Nd) scattering data provides direct insight into the three-nucleon forces (3NFs) of chiral effective field theory ($\chi$EFT). Wave-packet continuum discretization (WPCD) is a method that can efficiently approximate Nd scattering wave functions. In this talk I present a study where we developed a WPCD-code and sampled posterior predictive distributions (PPDs) of Nd observables, using recent high-quality posterior probability density functions for the low-energy constants of chiral two-nucleon forces (2NFs). This is a first step towards a Bayesian analysis of 2NFs and 3NFs from $\chi$EFT conditioned on Nd scattering data.

Speaker: Sean Miller (Chalmers University of Technology)

14:10 Mirror Symmetry and Proton Emission in the Upper fp Shell

An experimental campaign focusing on isospin-symmetry and proton emission in the upper fp shell was performed at Argonne National Laboratory (ANL) in 2020, with the nuclear structure group from Lund University leading three out of five experiments. The overarching goal was to perform in-beam high-resolution particle- and γ-ray coincidence spectroscopy. The first experiment focused on particle and γ-ray coincidence spectroscopy of 57Cu. The second experiment studied isobaric analog states in mass A = 61,62. The third experiment explored isospin symmetry at the limits of nuclear binding via proton-γ spectroscopy of 65As.
The focus of the campaign on proton spectroscopy called for a new approach in charged-particle detection. A very complex experimental setup comprising two CD-type double-sided Si-strip detectors (DSSDs) in combination with Microball detector was employed, in conjunction with the Gammasphere array, the Neutron Shell, and the Fragment Mass Analyzer (FMA). A novel combination of CD-DSSD (2 × 2048 pixels) detectors with the Microball array [Fig. 1 (b) and (c)] allowed to add proton tracking capabilities while keeping high particle detection efficiency.
The fusion-evaporation reaction 40Ca + 24Mg → 64Ge* at a beam energy of 106 MeV was used to populate excited states in 61Ga. Results from an earlier experiment concerning the Tz = 1/2 nucleus 61Ga imply a proton-emitting state at about 2.4 MeV excitation energy [Fig. 1 (a)]. Preliminary results from the ongoing analysis will be presented.

Speaker: Yuliia Hrabar

14:30 Stories from inside a magnet: solenoidal spectrometers

Fission barriers in neutron-rich nuclei provide essential input for understanding the astrophysical r-process, yet are extremely challenging to measure. Using direct kinematics is not possible for the investigation of short-lived isotopes. However, high-resolution studies of radioactive beams in inverse kinematics are feasible through the use of a solenoidal spectrometer. By exploiting the underlying kinematics of the reaction, the fission yields as a function of excitation energy can be investigated.
This contribution will include an overview of fission studies in inverse kinematics using solenoidal spectrometers. Features and caveats of this experimental approach will be discussed.

Speaker: Anna Kawecka (Chalmers University of Technology (SE))

kinematyka_Lund2022.pdf

14:50 Coffee

15:15 The potential of multi-strange physics with PANDA at FAIR

The production of antihyperon-hyperon pairs in antiproton-proton collisions is an excellent probe for studying the strong interaction in the non-perturbative regime. Here, the relevant degrees of freedom are unclear. The self-analysing decay of hyperons provides us with a way to investigate reaction dynamics by reconstructing spin observables. Furthermore, hyperon spectroscopy enables us to study how quarks form baryons, which forces are involved, and what the relevant degrees of freedom are.

The upcoming PANDA experiment at FAIR will be a veritable strangeness factory. The amounts of data it will produce in the multistrange sector, in particular, will be unprecedented, with some reaction channels becoming accessible for the first time.

Simulations have been carried out to explore the potential of PANDA to contribute to the various aspects of physics with multi-strange hyperons. This presentation will give an overview of these recent feasibility studies.

Speaker: Michael Papenbrock

Papenbrock_PANDA_Fysikdagarna_2022.pdf

15:40 Femto-science: Electromagnetic transition form factors of the nucleon

Understanding the structure of hadrons is the core mission of hadron physics. Electromagnetic form factors provide us an angle to understand the structure of hadrons. For instance, in the history of particle physics, by studying the electromagnetic form factors of electron-proton scattering one inferred the existence of partons, namely, quarks. In this talk, I will present a model independent study on the transition form factors of the Nucleon to its excitation $N^*(1520)$ using dispersion relations.

Speaker: Di An

Lund_Talk.pdf

16:00 The Structure of Something Strange

All matter that we encounter in our daily lives is made up of baryons. These, in turn, are built from quarks held together by the strong force. Because of the nature of the strong force, it is challenging to understand the interactions between the quarks and how these give the baryons the properties that we can observe. Despite a century of intense effort, the mechanisms behind properties like the mass and spin of even the most common baryons, the nucleons, are not fully understood. By studying the internal electromagnetic structure of the baryons we can learn more about how the quarks are arranged and consequently about the interactions that bind them together. The structure of nucleons has been and continues to be studied extensively, but it is valuable to also pursue other, parallel avenues of research. A complementary and relatively unexplored approach is to study hyperons, i.e. baryons that contain strange quarks, instead. The strange quark is considerably heavier than the up and down quarks and is therefore expected to have a different spatial distribution. What are the implications for the structure and what does this, in turn, tell us about the strong force? Answering these questions allows us to form a more general and complete understanding of how baryons are formed. Hyperons are unstable and this makes them complicated to study compared to the nucleons, but because their decays are "self-analyzing" they also offer unique opportunities. In this talk I will discuss how polarization, entanglement, and self-analyzing decays can be combined to study the electromagnetic structure of hyperons, and show recent results from the BESIII experiment at the Beijing Electron-Positron Collider (BEPCII) where this method has been applied to the $\Lambda$ hyperon.

Speaker: Viktor Thorén

Thoren_FD.pdf

16:20 Exploring the HADES Feb22 pp Run

During this spring the HADES experiment at GSI in Darmstadt, Germany had a total of 30 days of proton beam, producing pp reactions at 4.5 GeV beam kinetic energy. The main goal of this beam time is to study hyperon production and their electromagnetic decays. It is one of the FAIR Phase-0 projects, using FAIR equipment at the GSI facility. For this run the HADES spectrometer was accomplished by a Forward Detector which includes PANDA Straw Tube Tracking Stations.
While the detector calibration is ongoing, the simplest physics channel to look into is proton-proton elastic scattering. One can learn a lot about data quality by studying this channel including a luminosity measurement, quality control and normalization. Since the Forward Detector was added, three event topologies can be studied. While one proton is detected in the main HADES spectrometer, the other one can either be found in the same detector, or in the Forward Detector, or completely escape detection. Our measurements are compared to detailed differential cross-section measurements from other experiments at 4.15 GeV and 4.65 GeV, available by the database SAID. Apart from providing crucial input for the HADES physics program foreseen for this data campaign, these studies will contribute with new pp elastic cross-section measurements at intermediate energy.

Speaker: Jana Rieger (Uppsala University (UU))

fysikdagarna22.pdf

16:40 Physics Opportunities from the $pp \rightarrow KK \Lambda \Lambda$ Reaction Channel at HADES

Understanding the physics and inner workings of neutron stars has been a longstanding issue since their discovery in 1967. These incredibly dense stellar objects are formed from the collapse of supergiants, finding equilibrium by a neutron degeneracy arising in its interior. The development of accurate equation of state models has been hindered by the energetically favoured appearance of hyperons within neutron star cores due to the limited understanding of the ways in which they interact.

The femtoscopy method has proved to be a promising avenue for probing these hyperon interactions, where the HADES experiment at GSI has contributed with measurements. For future hyperon studies, a kinematic fitter has been developed at Uppsala University as part of HADES' software tools to improve the reconstruction of hyperons, an upgrade that allows for further femtoscopy studies as well. To be presented is a simulation project which aims to determine the performance of this fitter on the $pp \rightarrow KK \Lambda \Lambda$ production reaction, relevant for $\Lambda \Lambda$ femtoscopy studies.

Speaker: Malin Bohman

12:30 → 20:00 Undervisningssektionen (Gymnasie): Visit to ESS

Convener: Susanne Tegler

12:30 Registrering och kaffe

Samling på ESS (Partikelgatan 2 i Lund)

13:00 Introduktion ESS

13:15 Föreläsning "Experiment med neutroner vid ESS"

Overview ESS for Public.pdf

14:00 Föreläsning "Strålkällan vid ESS"

The European Spallation Source.pdf

14:45 Säkerhetsinformation inför rundtur

15:00 Fika

15:15 Ta på skyddskläder (grupp 2)

15:30 Workshop (grupp 1) Rundtur på ESS (grupp 2)

Gauss Rifle Worksheet_ESS.pdf

Hidden Shapes.pdf

16:30 Ta på alternativt ta av skyddskläder

16:45 Rundtur på ESS (grupp 1) Workshop (grupp 2)

17:45 Ta av skyddskläder och avslutning på ESS

18:30 Gymnasielärarträff med buffé på Fysicum

13:00 → 17:00 Sektionen för Gravitation: AF Borgen, VD-rummet

Convener: Håkan Andreasson

13:00 Roger Penroses insatser för relativitetsteori

Speaker: Ingemar Bengtsson

14:00 Roterande rumtider i allmän relativitetsteori

Speaker: Michael Bradley

15:00 Fika

15:30 Gravitational collapse and cosmic censorship for the Einstein-Vlasov system

Speaker: Håkan Andreasson

16:15 Some aspects of black hole stability

Speaker: Thomas Bäckdahl

13:00 → 17:10 Sektionen för atom-, molekyl- och optisk fysik: AF Borgen: Gustafscenen

13:00 Welcome and short introduction to AMO physics in Lund and Sweden

Speaker: Jan Marcus Dahlström

13:15 Cooling dynamics of nitrogen-containing PAH cations (PANHs)

Polycyclic aromatic hydrocarbons (PAHs) are a class of organic molecules based on two or more fused aromatic rings, with hexagonal rings as typical dominant constituents. They are found and formed in a wide variety of environments. In the case of extraterrestrial environments, PAHs are believed to be an important component in interstellar dust and gas and as such are responsible for infrared emission features that dominate the spectra of many galactic and extragalactic sources [1]. Numerous experimental and theoretical studies on PAHs have been carried out in the past decades, but how they may survive in space is still not fully understood [2].
PAHs that contain one or more nitrogen atoms are so-called polycyclic aromatic nitrogen heterocycles (PANHs). The existence of PANHs in space has been inferred by their detection in meteorites [3], and they may be present in the haze surrounding Saturn’s largest moon Titan [4]. Their presence in astrophysical environments is further supported by the recent discoveries of two interstellar nitrile group functionalized PAH molecules (1- and 2- cyanonaphthalene) [5] and one of the simplest nitrogen-bearing aromatic molecules (benzonitrile: c-C6H5CN) [6] in the TMC-1 molecular cloud. One key issue is the cooling dynamics of such molecules, which affects their abundances in the ISM [7].
The ultra-high vacuum and low-temperature environment provided by the DESIREE ion-beam storage ring facility [8] is ideal for following ultraslow molecular relaxation processes of astrophysical interest on timescales exceeding seconds, where fragmentation, recurrent fluorescence, and IR emission compete. In this talk, I will present such studies of PAH molecules with a focus on the spontaneous and laser-induced decays of acridine (C13H9N) and phenazine (C12H8N2) cations. Both molecules are members of the PANH family and consist of three planar aromatic rings but differ in that a C–H groups in the central anthracene ring have been replaced by one N to form acridine or two N to form phenazine. Fig.1 shows examples of the spontaneous decays of hot acridine and phenazine cations as monitored through the yields of neutrals due to unimolecular dissociation products as functions of ion beam storage time. These curves provide information on the characteristic radiative cooling times for which the decays are quenched, which together with results using laser probing techniques allow following the cooling dynamics in unprecedented detail.

References:
[1] A. G. G. M. Tielens, Ann. Rev. Astron. Astrophys. 46, 289 (2008) [2] C. Joblin and A. G. G. M. Tielens, EAS, EDP Sciences (2011) [3] P. G. Stoks and A. W. Schwartz, Geochim. Cosmochim. Acta 45, 563 (1981) [4] H. Imanaka, Icarus 168, 344 (2004) [5] McGuire et al., Science 371, 1265–1269 (2021) [6] McGuire et al., Science 359, 202–205 (2018)
[7] J. Montillaud, C. Joblin, and D. Toublanc, A&A 552, A15 (2013) [8] [1] R. D. Thomas et al., Rev. Sci. Instrum., 82(6):065112, 2011.

Speaker: Suvasthika Indrajith

13:40 Quantum computing in rare-earth-ion-doped crystals

Quantum computers are predicted to achieve significant speed-ups for certain applications when compared to classical computers. In this talk, I give an overview of quantum computing in rare-earth-ion-doped crystals, including the results of recent theoretical investigations that show that quantum processor nodes constructed in these materials can be tailored to contain between a few tens and 1000 qubits. Furthermore, the average number of qubits each qubit can interact with, denoted by the connectivity, can be partly tailored to lie between just a few and roughly 100.

Speaker: Adam Kinos (Lund University)

14:05 Ultrafast nanophotonics: from all-optical control of exciton dynamics towards plasmon-tailored nano-chemistry

Ultrafast control of light-matter interactions is fundamental in view of new technological frontiers, for instance in light-driven information processing and nanoscale photo-chemistry. In this framework, we explore metal-dielectric nanocavities to achieve all-optical modulation of the light reflectance at a specific wavelength. Without the need of driving higher order effects, our system is based on linear absorption, provides large relative modulation exceeding 100% and switching bandwidths of few hundred GHz at moderate excitation fluence [1]. This archetypical system becomes even more interesting if the “gain medium” is an inorganic van der Waals bonded semiconductor, like a transition metal dichalcogenide (TMD). TMDs are subject of intense research due to their electronic and optical properties which are promising for next-generation optoelectronic devices. In this context, understanding the ultrafast carrier dynamics, as well as charge and energy transfer at the interface between metals and semiconductors is crucial and yet quite unexplored. By employing a pump-push-probe scheme, we experimentally study how thermally induced ultrafast charge carrier injection affects the exciton formation dynamics in bulk WS2 [2], opening up excellent opportunities also in nano-chemistry. In fact, if a molecular transition strongly interacts with the light modes of a resonator, we can tailor the energetics and the morphology of the molecular electronic states. By combining quantum mechanical modelling and pump-probe spectroscopy, we shed light on the ultrafast dynamics of a hybrid system composed of photo-switchable dye molecules coupled with optically anisotropic plasmonic nanoantennas, which allow us to selectively switch between two regimes where the light-matter interaction is either weak or strong [3]. Our synergistic approach is instrumental to devise new strategies for tailoring electronic states by using plasmons for applications in polaritonic chemistry on femtosecond timescales.

References
[1] J. Kuttruff, D. Garoli, J. Allerbeck, R. Krahne, A. De Luca, D. Brida, V. Caligiuri, and N. Maccaferri. “Ultrafast all-optical switching enabled by epsilon-near-zero-tailored absorption in metal-insulator nanocavities”, Commun. Phys. 3, 114, 2020.
[2] K. R. Keller, R. Rojas-Aedo, H. Zhang, P. Schweizer, J. Allerbeck, D. Brida, D. Jariwala, and N. Maccaferri. “Sub-ps thermionic electron injection effects on exciton-formation dynamics at a van der Waals semiconductor/metal interface”, arXiv:2202.03818.
[3] J. Kuttruff, M. Romanelli, E. Pedrueza-Villalmanzo, J. Allerbeck, J. Fregoni, V. Saavedra-Becerril, J. Andreasson, D. Brida, A. Dmitriev, S. Corni, and N. Maccaferri. “Ultrafast dynamics of a hybrid plasmon polariton-molecular system at the weak and strong coupling regimes”, submitted.

Speaker: Dr Nicolò Maccaferri (Umeå University)

14:30 Atomic astrophysics for Galactic evolution

The chemical composition of a star provides information about the environment in which it was born. This, in turn, makes it possible to study the formation and evolution of our Galaxy. Reliable abundance analysis of various elements in stellar spectra require an understanding of the atomic nature, in the form of accurate atomic transition data. By combining radiative lifetimes with relative emission line ratios, so called branching fractions, from Fourier Transform Spectroscopy measurements, we can derive oscillator strengths for astronomically important transitions.
We present our current project of astronomical relevance: the spectrum of neutral aluminium, Al I. Aluminium is specifically found in young, massive stars, which makes it a key element for mapping out ongoing nucleosynthesis throughout the Galaxy. Comparing experiment to theoretical calculations helps confirm and further improve atomic structure codes. The combination of these two methods, in turn, allows for an even more accurate stellar abundance analysis, as well as a better understanding of the atomic structure.

Speaker: Madeleine Burheim

14:40 Understanding Dynamic Calculations of Anharmonic Infrared Spectra

The infrared spectrum of a molecular system is traditionally calculated from energy derivatives at its equilibrium geometry. Such methods are inherently limited to a single static point, and cannot describe anharmonic potential features such as the ergodic double-well. A more recent approach is to simulate classical vibration with Born-Oppenheimer molecular dynamics, freely exploring the potential surface. The trajectory is then processed into an infrared spectrum using the Fermi Golden Rule. I will explain why this approach works, and compare its results on toy and real systems to that of static methods. I will also discuss the role of the most important numerical parameters.

Speaker: Åke Andersson

14:50 On the interplay of fluorescence, dissipation, and molecular dissociation for a model diatomic molecule in a quantum optical cavity

Speaker: Megha Gopalakrishna

15:00 Coffee break

15:30 Shooting X-rays at the nitrogen molecule like it's 2022

Using synchrotron radiation and state of the art instruments we uncover more about the electronic structure of N$_2$. In this presentation we will look at new core-excited states in N$_2^+$ studied by X-ray absorption spectroscopy and how the vibrational wavefunction of N$_2$ can be imaged by resonant inelastic X-ray scattering.

Speaker: Ludvig Kjellsson (MAX IV Laboratory)

15:55 Exploring crystallisation in ”no man’s land’

The region in the water’s phase diagram called “no-man’s land” (160K - 232 K) [1,2] has incited vast research. It is within its depths that the origin of water’s anomalous properties is thought to hide behind a veil of crystallisation [3,4]. However, there are other open questions in this region regarding the early stages of crystallisation itself, particularly that of the structure of ice. The main hurdle to overcome has been that water spontaneously crystallises as either bound of “no-man’s land” is approached.
We succeeded in navigating this region by applying ultra-fast heating using an infrared laser on amorphous ices, followed by femtosecond X-ray scattering measurements at different delay times. After the observation of a liquid-liquid transition[5], the curtain fell and crystallisation started, allowing us to probe the early stages of crystallisation[6]. We observed that the crystallising phase is stacking disordered ice (Isd) with a high cubicity which decreased over time. We note that a growing small portion of hexagonal ice (Ih) was also present, suggesting that already within our timeframe, Isd starts annealing into Ih.

References:

[1] R. S. Smith, B. D. Kay, Nat. 1999, 398, 788–791.
[2] B. J. Mason, Adv. Phys. 1958, 7, 221–234.
[3] P. Gallo, K. Amann-Winkel et al., Chem. Rev. 2016, 116, 7463-7500
[4] K. Amann-Winkel, C. Gainaru et al., PNAS. 2013, 110, 17720
[5] K. H. Kim et al., Science. 2020, (80). 370, 978–982
[6] M. Ladd-Parada et al., J. Phys. Chem. B. 2022,126, 2299-2307

Speaker: Marjorie Ladd Parada (Stockholms Universitet)

16:20 Relativistic laser-electron acceleration from nanotargets

The interaction between ultraintense laser light (10^20 W/cm2) and nanotips can produce electron bunches with interesting properties, such as relativistic energy (1-10MeV), high charge (nC) and pulse duration expected in the attosecond regime. Experimental results about the angular distribution, charge and spectrum will be shown and explained using the vacuum laser acceleration mechanism.

Speaker: Aitor De Andres Gonzalez

16:30 A Levitating Droplet as a Toy Atom

There very first example a student learns in quantum mechanics is the square potential well. However, when working with atoms we use spherical coordinates and a spherical potential well would be a much closer analogy. After writing the Schrödinger equation in spherical coordinates, the centrifugal barrier ($\ell (\ell + 1) /r^{2}$) appears, which, when added to a square potential well in the radial coordinate, results in a wedged potential well.

In this work, we use an optical trap and a water droplet to create an experiment with exactly such wedged potential wells. The equation for the scattering intensity obtained directly from the Maxwell equations turns out identical to the radial, Schrödinger equation, where the light trapped in resonating modes inside the droplet is analogous to an electron trapped in an atomic potential.

The width of the radial square well is smoothly changed by changing the radius of the droplet resulting in a directional Mie scattering spectrum consisting of a series of Fano resonances. This again points to the analogy with an atom, since Fano resonances were first discovered for inelastic electron scattering by helium atoms. The resonances are ordered by the integer angular momentum value, $\ell$, associated with the rotation of the light as it reflects inside the surface of the droplet. In an atomic system, this would be the angular momentum of the electron.

The full spectrum consists of a series of consecutive Fano Combs, each with dozens of individual resonances evolving from wide Lorentzian shapes to sharp asymmetrical Fano profiles. We use the analogy with the Schrödinger equation to fully and intuitively explain the Fano Comb structure. This results in a model experiment for an atom with a knob to control the atom's properties including the potential's width and depth, that \textbf{scans over a wide range of angular momenta}. The spectrum gives a full picture of the range of possible resonances in such a toy atomic system.

Speaker: Javier Tello Marmolejo

16:40 fs-recombination in Fe-based solar cells limits the performance

It has been widely recognized in the scientific community that scarce elements such as ruthenium are not ideal for sustainable technology. During the past 10 years, progress has been made in exploring first-row transition metals as replacements for scarce metals in many solar cell and photocatalysis applications.[1] Iron analogues to well-performing ruthenium-complexes were early found to not yield nearly the same solar cell performance, despite Ru and Fe being congeners.[2] Prior to our efforts, by means of ultrafast spectroscopy it was found that the relevant excited state deactivates in less than a ps, a timescale not accessible for most electron-transfer reactions.[3] Nowadays many examples of Fe-based complexes with ps-ns lifetimes have been demonstrated, mainly realized by the carbene-ligand.[4]
In the work described here, a set of push-pull Fe-carbene complexes have been characterized by means of time-resolved spectroscopy both in solution and after sensitization of titania nanoparticles.[5] In this way, parts of the dye-sensitized solar cell responsible for interfacial electron-transfer between the dye and the semiconductor are recreated, making it possible to study these processes. Creating rod-like push-pull complexes is a key strategy to facilitate charge separation in solar cells, and to mitigate charge recombination. Our results show that indeed electron injection into titania happen within 100 fs after excitation[5] and is highly efficient.[6] However, recombination leaves only ~10 % of the initially injected electrons for the timescale accessible to contribute to solar cell performance. Moreover, the recombination was found to take place mainly with a time constant of 100 fs and return the dye molecules to their excited state.[5] The discovery of the ultrafast recombination reaction identifies a key bottleneck that limits the development of Fe-based solar cells, something that would never have been found without employing ultrafast characterisation techniques.

[1] O.S. Wenger, Photoactive Complexes with Earth-Abundant Metals, J. Am. Chem. Soc. 140 (2018) 13522–13533. https://doi.org/10.1021/jacs.8b08822.
[2] S. Ferrere, B.A. Gregg, Photosensitization of TiO2 by [FeII(2,2‘-bipyridine-4,4‘-dicarboxylic acid)2(CN)2]: Band Selective Electron Injection from Ultra-Short-Lived Excited States, J. Am. Chem. Soc. 120 (1998) 843-844. https://doi.org/10.1021/ja973504e
[3] J. E. Monat, J. K. McCusker, Femtosecond Excited-State Dynamics of an Iron(II) Polypyridyl Solar Cell Sensitizer Model, J. Am. Chem. Soc. 122 (2000) 4092–4097. https://doi.org/10.1021/ja992436o
[4] L. Lindh et al., Photophysics and Photochemistry of Iron Carbene Complexes for Solar Energy Conversion and Photocatalysis, Catalysts 10 (2020) 315. https://doi.org/10.3390/catal10030315
[5] L. Lindh et al., Dye-Sensitized Solar Cells based on Fe N-heterocyclic Carbene Photosensitizers with Improved Rod-like Push-Pull Functionality, Chemical Science 12 (2021) 16035-16053. https://doi.org/10.1039/d1sc02963k
[6] T. Harlang et al., Iron sensitizer converts light to electrons with 92% yield, Nature Chemistry 7 (2015) 883-889. https://doi.org/10.1038/nchem.2365

Speaker: Linnea Lindh (Chemical Physics/Theoretical Chemistry Lund University)

16:50 Multiconfigurational effects in an iron-nitrosyl (FeNO) complex.

Nitrosyl-containing iron complexes (FeNO) have attracted many studies focusing on the mechanisms of NO binding in heme and NO release by a photoactivated nitric oxide-releasing moiety complex. M-NO and M-CO bonds form by $\sigma$-donation to an unoccupied metal orbital and the bond is strengthened by $\pi$-back donation from a filled metal d-orbital to the unoccupied $\pi^*$ orbitals on the ligand. Unlike M-CO bonds which are linear, M-NO bonds are often bent, resulting from one extra electron residing in the NO $\pi^*$. Hence fluctuations between linear and bent FeNO bonds occur and are correlated to the placement of the extra electron in either the partially occupied d-orbitals or in one of the unoccupied NO $\pi$* ligand orbitals. The understanding of the complex bonding by means of theory and computation requires a multiconfigurational approach. In the present work, we consider fluctuations in geometric and electronic properties by the sampling structures from an ab intio molecular dynamics (AIMD) simulation. Theoretical calculations (CASSCF and NEVPT2) reveal strong correlations between sampled properties and the principle Fe-N reaction coordinate. In addition to these correlations, we find that fluctuations of electronic character occur leading to a multireference description of the oxidation state of the iron metal center.

Speaker: Michael Coates (Stockholms universitet)

17:00 A Green's function method for the two-dimensional frustrated spin-1/2 Heisenberg magnetic lattice

Speaker: Zhen Zhao

13:00 → 17:05 Sektionen för elementarpartikel och astropartikelfysik: AF Borgen: Nya Fest

Conveners: David Silvermyr (Lund University (SE)), Rikkert Frederix (Lund University)

13:00 Phase Transition and Gravitational Wave of Strongly Coupled Dark Sectors

We go beyond the state-of-the-art by combining first principal lattice results and effective field theory approaches as Polyakov Loop model to explore the non-perturbative dark deconfinement-confinement phase transition and the generation of gravitational-waves in a dark Yang-Mills theory. We further include fermions with different representations in the dark sector. Employing the Polyakov-Nambu-Jona-Lasinio (PNJL) model, we discover that the relevant gravitational wave signatures are highly dependent on the various representations. We also find a remarkable interplay between the deconfinement-confinement and chiral phase transitions. In both scenarios, the future Big Bang Observer experiment has a higher chance to detect the gravitational wave signals.

Speaker: Dr Zhi Wei Wang (Lund University)

Strongly Coupled Sectors and GW_v1_Lund.pdf

13:15 The electroweak phase transition and Effective Field Theory

About a picosecond after the Big Bang, when the universe had cooled down to a temperature of around 100 GeV, the electroweak symmetry was broken, as the Higgs field condensed into a state with a non-zero vacuum expectation value. This process is known as the Electroweak Phase Transition (EWPT). If the EWPT was a first-order phase transition, it was an abrupt and violent process with formation of bubbles of the new phase, whose dynamics could potentially explain the observed baryon-antibaryon asymmetry of the universe, and it could also yield a detectable gravitational wave background.

The Standard Model, however, predicts a smooth transition. This can be traced back to the large Higgs mass that makes a first-order transition impossible. Going beyond the Standard Model, a first-order transition could be possible, for example through new scalar fields with masses close to the electroweak scale that contribute to the Higgs potential. It is also possible that the new physics may be heavier, and to investigate this we have studied the EWPT in the Standard Model Effective Field Theory (SMEFT) with higher dimension operators. I will discuss various possibilities for obtaining a strong first-order EWPT in the SMEFT and in other theories, and the theoretical and experimental constraints. I will also briefly discuss the prospects for probing the allowed parameter space using di-Higgs production in colliders.

Speaker: Rikard Enberg

Partikeldagarna 2022.pdf

Partikeldagarna 2022.pptx

13:30 New methods for studying the Electroweak phase transition

Gravitational waves offer a new way to understand the Higgs via the Electroweak phase transition. The signal from such a transition would, if observed, give crucial information of the underlying physics. Provided that the transition is first-order and proceeds through nucleating bubbles. Yet theoretical predictions of the gravitational-wave spectrum are rife with uncertainties. Large ones at that—spanning several orders of magnitude for some models. Fortunately, many uncertainties can be reduced by using modern EFT techniques. In this talk I give an overview of these results. To be specific, I review state-of-the-art techniques for calculating the bubble-nucleation rate and related observables at high temperatures. In addition, I discuss when conventional methods fail, and how far we can trust perturbation theory.

Speaker: Andreas Ekstedt

FysikDagarnaAE.pdf

13:45 Fingerprints of freeze-in dark matter in an early matter-dominated era

We study the impact of an alternate cosmological history with an early matter-dominated epoch on the freeze-in production of dark matter. Such early matter domination is triggered by a meta-stable matter field dissipating into radiation. In general, the dissipation rate has a non-trivial temperature and scale factor dependence. Compared to the usual case of dark matter production via the freeze-in mechanism in a radiation-dominated universe, in this scenario, orders of magnitude
larger coupling between the visible and the dark sector can be accommodated. As a proof of principle, we consider a specific model where the dark matter is produced by a sub-GeV dark photon having a kinetic mixing with the Standard Model photon. We point out that the parameter space of this model can be probed by the experiments in the presence of an early matter-dominated era.

Speaker: Dr Avik Banerjee (Chalmers University of Technology)

talk_Freezein_Lund2022.pdf

14:00 Phase transitions: A source of cosmic-frontier phenomenology

In this talk, I will present a short overview of the connection between particle physics and phase transitions in the early and very early universe. I will then focus on phase transitions during inflation and present recent results on how to use the stochastic spectral expansion to perform phenomenology calculations. I will also talk about the interplay between the electroweak phase transition, new physics at the TeV-scale and experimental constraints.

Speaker: Eliel Camargo-Molina (Uppsala University)

Partikeldagarna2022.pdf

14:15 CDF II W-mass anomaly faces first-order electroweak phase transition

We suggest an appealing strategy to probe a large class of scenarios beyond the Standard Model simultaneously explaining the recent CDF II measurement of the W boson mass and predicting first-order phase transitions (FOPT) testable in future gravitational-wave experiments. Our analysis deploys measurements from the gravitational waves channels and high energy particle colliders. We discuss this methodology focusing on the specific example provided by an extension of the Standard Model of particle physics that incorporates an additional scalar SU(2)_L triplet coupled to the Higgs boson. We show that within this scenario a strong electroweak FOPT is naturally realised consistently with the measured W boson mass-shift. This model can be tested in future space-based interferometers such as LISA, DECIGO, BBO, TianQin, TAIJI projects and in future colliders such as FCC, ILC, CEPC.

Speaker: Roman Pasechnik (Lund university)

Fysikdagarna22-Pasechnik.pdf

14:30 A fermionic portal to a non-abelian dark sector

I will present a new class of renormalisable models, labelled Fermion Portal Vector Dark Matter, consisting of a dark SU(2)D gauge sector connected to the Standard Model through a Vector-Like fermion mediator, not necessarily requiring a Higgs portal, in which a massive vector boson is the Dark Matter candidate. Multiple realisations are possible, depending on the properties of the VL partner and of the scalar potential. These models have a large number of applications with significant implications for cosmology, collider physics and flavour observables, depending on the mediator sector.

Speaker: Luca Panizzi (Uppsala University)

FPVDM3.pdf

14:45 Speeding up SM Amplitude Calculations with Chirality Flow

Two years ago, we introduced a new method to calculate Feynman diagrams more efficiently and transparently, the Chirality-Flow formalism. In this framework, which builds on the spinor-helicity formalism, analytic, tree-level Standard Model Feynman diagrams can be written down almost immediately as a complex number, without the need for intermediate algebra. In this talk, as a proof-of-concept, I will discuss how using Chirality-Flow for massless QED makes MadGraph5_aMC@NLO a factor 2-10 times faster for processes with up to 7 final-state particles, with increasing speed gain for higher multiplicity.

Speaker: Andrew Lifson

ALPartikeldagarna2022.pdf

15:00 Break

15:30 Status of the Light Dark Matter KAW project

This contribution provides an overview of the status of the Knut and Alice Wallenberg project “Light Dark Matter”, a collaboration between experimental and theoretical particle and nuclear physicists from Lund University, Chalmers and Stockholm University. The project addresses the possible existence of sub-GeV dark matter in a very comprehensive way. Its activities range from the setup of a new, highly-sensitive experiment, LDMX, to discover such particles, over the development of software tools for simulations and statistical interpretation of the data, to connections and input to other existing and future experiments including direct detection. In this talk, we will review the motivation and goals of the project, report on recent activities and progress, and give an outlook on the next steps.

Speaker: Timon Emken

Fysikdagarna2022_Emken.pdf

15:45 The SHIFT project: status and prospects

SHIFT (Solving the Higgs Fine-tuning problem with Top partners) is a Swedish theory-experiment collaboration with participants from Chalmers, Stockholm University and Uppsala, which is funded by KAW between January 2018 and June 2023. The aim of the project is to develop new models and search for top partners which could potentially explain the low mass of the Higgs boson, as well as perform precision measurements of processes involving top quarks, with the same goal. In this talk, we present the latest result from our studies of supersymmetry, composite Higgs models and indirect searches.

Speaker: Elin Bergeaas Kuutmann (Uppsala University (SE))

SHIFT_project_elin_Partikeldagarna2022.pdf

SHIFT_project_elin_Partikeldagarna2022.pptx

16:00 Searching for Vector Dark Matter at Beam Dump Experiments

Beam dump experiments place strong constraints on the parameter space of interesting sub-GeV dark matter (DM) models. We extend the current literature, which mainly focuses on the predicted signals of scalar and fermionic DM at beam dump experiments, by considering simplified DM models where the Standard Model is extended by one vector DM candidate along with one spin-1 or spin-0 mediator. In this analysis, we determine the parameter space which gives rise to the observed thermal relic abundance and predict the sensitivity of current and future beam dump experiments (such as LDMX) in addition to other complimentary experiments on these models. We explore the effect of the DM mass, mediator mass, and couplings on these constraints, considering both on-shell and off-shell DM production.

Speaker: Taylor Gray

Fysikdagarna_Lund2022_TaylorGray.pptx

16:15 General Dark Matter Electron Interactions in Detector Materials

We develop a novel formalism to describe the scattering of dark matter (DM) particles by electrons bound in detector materials such as silicon, germanium and graphene for a general form of the underlying DM-electron interaction. By applying non-relativistic effective field theory methods, we find that the DM and material physics factorise into a handful of DM and material "response functions". The former are obtained by taking the non-relativistic limit of the free amplitude for DM-electron scattering, whereas the latter are expressed in terms electron wave-function overlap integrals and obtained using Density Functional Theory. To illustrate the potential of our formalism, we predict scattering rates for DM-electron interactions that were not accurately tractable before, such as the magnetic dipole interaction.

Speaker: Einar Urdshals

Urdshals_Lund_talk.pdf

16:30 RECFA/CERN

Speakers: Arnaud Ferrari (Uppsala University (SE)), David Anthony Milstead (Stockholm University (SE))

RECFA-ECFA-upload.pptx.pdf

16:45 IUPAP

Speakers: Roman Pasechnik (Lund university), Roman Pasechnik (Lund university)

IUPAP-talk-Pasechnik_2022.pdf

17:00 News from ACCU (slides only, no presentation)

Speaker: Rebeca Gonzalez Suarez (Uppsala University (SE))

ACCU_PartikelDagarna2022.pdf

13:15 → 14:15 Undervisningssektionen (Physics Education Research): Fysikum, Sal D (L315)

Convener: Urban Eriksson (Lund University)

13:15 Teaching with open research data: experiences from five years of exploration-driven lab exercises in subatomic physics for undergraduate students

Over the past five years we have guided over 400 undergraduate university students to quite independently finding and measuring properties of subatomic particles in real research data from the ATLAS experiment at CERN. I will discuss our experiences with designing lab exercises using real research data, technical challenges and how we solved them, the gradual improvements we implemented from year to year, as well as some personal reflections on perceived pedagogical benefits from learning via curiosity-driven exploration. The presentation may also include a live demonstration and quick guide to how the computer lab is set up, and/or some indications of how well these types of labs work for high school students.

Speaker: Christian Ohm (KTH Royal Institute of Technology (SE))

KTH_open-data_labs.pdf

13:45 Linking Programming to Representations

Within the physics discipline exists a plethora of different equations, graphs, words, and gestures. Each of these are constructed to represent a specific aspect of a physical system or concept. One way to construct and manipulate representations is by programming simulations of physical concepts. The visualisations created from the simulations are constructed to capture and showcase a specific aspect of the physical concept. By using social semiotics and variation theory of learning to describe the role of programming in the construction of representations, and consequently, the role of programming in the meaning-making process, the affordances of programming may be described.
To fully describe students’ creation and manipulation of representations, the framework of social semiotics had to extended with new constructs to better describe students’ movements between different types of representations: Transductive Links and Active and Passive transductions.
This presentation aims to capture the ideas of Kim Svensson’s PhD Thesis, with the same name, on the subject of physics education research.

Speaker: Kim Svensson (Lund University)

17:00 → 19:00 Plenary session: Poster session, AF Borgen Athen

Thursday 16 June

08:30 → 08:35 Welcome, AF Norgen, Stora salen (5)

welcome.pdf

08:35 → 08:45 LINXS intro (10)

Speaker: Elizabeth Blackburn (Lund University)

LINXS_presentation_SFS_2022-06-16.pdf

LINXS_presentation_SFS_2022-06-16.pptx

08:45 → 09:25 MAX IV (30+10)

Speaker: Stephen Molloy

01_Stephen_Molloy_MAXIV.pdf

01_Stephen_Molloy_MAXIV.pptx

09:25 → 10:05 ESS (30+10)

Speaker: Andreas Schreyer

02 Andreas Schreyer_ESS Update June 2022.pptx

10:05 → 10:30 Fika

10:30 → 11:00 LINXS: Bio-medical imaging using synchrotron radiation (20+10)

Speaker: Martin Bech

03_Martin Bech FysikDagarna_MB_Imaging.pdf

03_Martin Bech FysikDagarna_MB_Imaging.pptx

11:00 → 11:30 LINXS: X-ray spectroscopy in the service of catalysis for renewable chemicals and fuels (20+10)

Speaker: Sara Blomberg

04_Sara Blomberg_talk_timesnewroman.pdf

04_Sara Blomberg_talk_timesnewroman.pptx

11:30 → 12:00 Antihydrogen and the ALPHA and GBAR experiments (20+10)

Speaker: Svante Jonsell

Fysikdagarna.pdf

Fysikdagarna.pdf

Fysikdagarna.pptx

12:00 → 12:45 Lunch (included)

12:45 → 12:50 Welcome to Lund (Mayor of the City of Lund)

Speaker: Mats Helmfrid

12:50 → 13:35 FAIR and strong interaction matter in the universe (35+10)

The strong interaction described by quantum chromodynamics gives rise to the formation of hadrons and nuclei that constitute the baryonic matter in the Universe and governs the densest matter in neutron stars and highest temperatures reached in compact object mergers. Combined with the electroweak interaction, it determines the structure and properties of all nuclei in the nuclear chart in a similar way as quantum electrodynamics shapes the periodic table of elements. However, big science problems of the strong interaction remain unsolved, especially regarding the structure of extreme neutron-rich matter in the laboratory and stars.

FAIR and other new facilities will discover over a thousand new isotopes, getting as close as possible to the nuclei in the Universe's heavy-element nucleosynthesis pathway. On the theoretical side, there are impressive advances towards a unified description of all nuclei and matter based on effective field theories of the strong interaction. This talk will discuss the advances and challenges in understanding strongly interacting matter, with a focus on the physics and astrophysics of NUSTAR at FAIR.

Speaker: Achim Schwenk (TU Darmstadt)

Schwenk_Lund_2022.pdf

13:35 → 14:30 Investigative Science Learning Environment (ISLE): When learning physics mirrors doing physics (45+10)

The Investigative Science Learning Environment (ISLE) approach is an intentional approach to learning and teaching physics that has two major goals: to systematically engage students in the activities that mirror scientific practice while they are constructing and applying new knowledge and to help them grow as learners and be empowered during that process. The former means that everything that happens in the classroom and at home related to students learning of physics mirrors the activities in which practicing scientists engage. The latter means that the decisions that the instructor makes while planning, enacting, and assessing the instruction support student intellectual and emotional growth. In my talk I will discuss how the ISLE approach addresses these goals in practice and share the research findings collected in the studies of ISLE students and ISLE teachers.

Speaker: Eugenia Etkina

ISLE Talk Lund.pdf

14:30 → 14:50 Fika

14:50 → 15:35 CERN, LHC and the Higgs (35+10)

Sweden was among the twelve countries that founded CERN - the European Laboratory for Particle Physics - in 1954. Since then it has grown into a scientific melting pot where thousands of physicists from all over the world work together to uncover what the universe is made of and how it works. Ten years ago, the ATLAS and CMS experiments at CERN's Large Hadron Collider (LHC) discovered the Higgs boson, a central ingredient in the standard model of particle physics. In only a few days, the LHC will start it's third run after a period of extensive upgrades. The new data will allow the physicists to search for the physics beyond the standard model that is needed to explain for instance the dark matter in the universe and the asymmetry between matter and antimatter.

Speaker: Sara Strandberg (Stockholm University (SE))

fysikdagarna_strandberg_220616.pdf

15:35 → 16:30 Challenges for women's careers in physics (45+10)

Speakers: Meytal Eran Jona, Yosef Nir

women_in_physicsr_LUND_06-22_meytal_final.pdf

18:30 → 22:00 Conference dinner (included). AF Borgen Stora salen. After dinner: Troels Petersen: The modelling of Covid-19

Friday 17 June

09:00 → 12:00 Parallel session: Parallel sessions

09:00 → 11:50 Sektionen för elementarpartikel och astropartikelfysik: Institutionen för astronomi och teoretisk fysik, Lundmarkssalen

09:00 The ESSnuSB Experiment - Conceptual Design and Physics Potential

The ESSnuSB experiment is a proposed long-baseline neutrino beam experiment that will measure the CP violation in the lepton sector. The CP violation will be determined by measuring the neutrino beam at the second probability maximum for muon neutrino oscillation into electron neutrinos, where the systematic uncertainty in the measurement is significantly reduced compared to the first oscillation maximum. The required high intensity neutrino beam will be produced with the high-intensity proton accelerator at the European Spallation Source (ESS) in Lund, Sweden. Within the ESSnuSB proposal the ESS proton accelerator will be upgraded to accommodate a doubling of the intensity, and an accumulator ring will be added to shorten the pulse-length by three orders of magnitude. The proton beam pulses will be distributed over four granular titanium targets to produce secondary particles, primarily pions, that are collimated and charge-selected using focusing horns. The pions will decay-in-flight to muons and neutrinos, where the selected sign of the pions determines if neutrinos or anti-neutrinos are produced. The neutrino beam will then be measured in the un-oscillated state with a near-detector complex on the ESS premises, using three different detector technologies. After this it will propagate 360 km to the water-Cherenkov far-detector in Zinkgruvan, north of Vättern lake, where the oscillated beam will be measured.

The ESSnuSB Conceptual Design Report is in the final stages of preparation, and will be presented here along with the evaluated physics potential for discovery of leptonic CP violation and, in particular, precision measurements of the CP violating phase.

Speaker: Prof. Tord Ekelöf (Uppsala University)

T.Ekelöf ESSnuSB och ESSnuSB+ Partikeldagarna 17 juni 2022.pdf

T.Ekelöf ESSnuSB och ESSnuSB+ Partikeldagarna 17 juni 2022.pptx

09:15 Latest Results from the IceCube Neutrino Observatory

The IceCube Neutrino Observatory, built into a cubic kilometer of ice at
the South Pole, was completed in 2010 and has been in continuous
operation since then. Discovering the diffuse astrophysical neutrino
flux in 2013, and pinpointing the first high-energy neutrino sources
starting in 2018, IceCube has inaugurated the era of neutrino
astronomy. Progress has been not only incremental but occasionally
revolutionary, a result of large advances in computing that could not
have been foreseen when the detector was built. Such advances include
the detailed modeling of photon propagation in the glacial ice, and the
application of Deep Learning to event selection and reconstruction. In
this talk, I will review some of the latest results from IceCube, with
an eye toward where such innovations have had a large impact.

Speaker: Chad Finley (Stockholm University / OKC)

Finley_IceCube_Partikeldagarna_2022.pdf

09:30 Probing X-ray bright blazars as sources of high-energy astrophysical neutrinos with IceCube

X-ray emission from blazars can be a useful tool to constrain their neutrino flux, assuming hadronic gamma-rays cascade down due to absorption inside source and secondary pair production. This approach was useful in disfavoring a single zone model for high-energy neutrino emission from the blazar TXS 0506+056, and more recently in the case of FSRQ PKS 1502+106 to hint at the presence of a hadronic component during its quiescent and flaring states. In this work, we test the neutrino emission potential of 1000 (soft) X-ray bright blazars by performing an untriggered search for neutrino flares from their direction in 10 years of IceCube data. We stack all flares from a source location to boost the significance of time-dependent emission, and perform population tests for FSRQs and BL Lacs in our catalog using the binomial test statistic.

Speaker: Ankur Sharma

fysikdagarna_Xray_blazars_Ankur_170622.pdf

09:45 Detection horizon of neutrinos from core-collapse supernovae using high energy neutrinos

Large-scale neutrino telescopes like IceCube monitor for supernovae using low energy neutrinos O(10 MeV), with a detection horizon out to the Magellanic Clouds. However, some models predict the emission of high-energy neutrinos O(>TeV) in core-collapse supernovae through the interaction of the ejecta with the circumstellar material or through choked jets. In this talk, I will explore the detection horizon of high-energy neutrinos emitted from core-collapse supernovae for the IceCube telescope, demonstrating that the reach for these objects can be pushed past the LMC and out to the neighboring galaxies in the Mpc range.

Speaker: Nora Valtonen-Mattila

Nora_Valtonen_Mattila_Fysikdagarna_2022.pdf

10:00 Break

10:30 New opportunities with IceCube-Gen2

The IceCube Neutrino Observatory is the world-leading instrument for astrophysical neutrino measurements. In the coming decade, we plan for IceCube-Gen2, which will include an expanded optical array with a factor of ~ 8 more instrumented volume and the addition of a radio array to extend the energy reach up to the EeV scale. Gen2 will move from the discovery era of astrophysical neutrinos to allow for robust observation of astrophysical neutrino sources, and will probe new territory in the highest energies. Here I will discuss the new opportunities for science expected with Gen2, including multi-messenger observations of sources, new classes of sources that can be observed, improvements in supernova neutrino detection and improved reach for BSM physics. I will also discuss the role Sweden will play in Gen2, toward both the planned radio and optical arrays.

Speaker: Erin O'Sullivan

Partikeldagarna2022_eosullivan.pdf

10:45 Pulsars do not produce sharp spectral features in the cosmic-ray positron flux

Pulsars dominate the local cosmic-ray positron flux at high energies by producing electron-positron pairs from their spindown energy. While the AMS-02 experiment, that measures the cosmic-ray flux to great precision, shows that the positron flux is very smooth, simple simulations of pulsar models predict sharp spectral features. In this work, we add several mechanisms to model the local positron flux more realistically. Specifically, we implement a more realistic positron production mechanism of the pulsars, and take into account variations in the magnetic fields and interstellar radiation fields that affect the energy losses of the positrons as they propagate through the Galaxy. Our models show that the sharp spectral features predicted by the simple models vanish, which is consistent with the observed smoothness of the local cosmic-ray positron flux.

Speaker: Isabelle John (Stockholm University)

Fysikdagarna_2022_IsabelleJohn.pdf

11:00 HIBEAM at the ESS - status and plans

In this talk I present the status of the "HIBEAM at the ESS" research project. The High Intensity Baryon Extraction and Measurement (HIBEAM) is the first stage of the two-stage experiment HIBEAM-NNBAR program and addresses major open questions in modern physics, in particular the origin of the observed matter-antimatter asymmetry and the nature of dark matter, with unique discovery potential, complementary to other worldwide experiments. The work comprises pre-studies, for the design of the HIBEAM instrument at the European Spallation Source (ESS). The two year program of work is split into four categories - beamline design and optimization, design and prototype of detectors for neutron-antineutron conversion searches, and the design of neutron detectors for dedicated sterile neutron searches. The work is funded with a VR RFI grant and brings together world-leading expertise from four Swedish institutes (Stockholm, Uppsala and Lund Universities and Chalmers Institute of Technology) and external scientists from the Institut Laue Langevin in Grenoble and Tennessee University, respectively. The project also involves the wider HIBEAM/NNBAR collaboration.

Speaker: Bernnhard Meirose (Stockholms Universitet + Lunds Universitet)

Meirose_Partikeldagarna2022_v2.pdf

11:15 ALICE activities in Lund

In the ALICE group at Lund, we analyse data from proton-proton and heavy-ion collisions to gain a better understanding of the connection between microscopic QCD processes and the properties of nuclear matter at high temperature and energy density. We will also discuss the hardware activities in our group, particularly our contributions to the ongoing and planned detector upgrades in light of the upcoming Runs 3 and 4 at the LHC.

Speaker: Alice Ohlson (Lund University (SE))

aohlson_partikeldagarna2022.pdf

09:00 → 12:00 Undervisningssektionen (Gymnasie)

09:00 Föreläsning "Magneter och människor – MR i forskning och medicin" (Fysicum K404)

Karin Markenroth Bloch
Forskare och föreståndare för den nationella 7T-anläggningen, Lunds Universitet

Speaker: Karin Markenroth Bloch

Magneter_och_människor–MR_i_forskning_och_medicin.pdf

09:01 Workshop "Investigative Science Learning Environment and student learning of energy" med fika (Fysicum H421), fully booked

Eugenia Etkina (Rutgers University, USA) and Gorazd Planinsic (University of Ljubljana, Slovenia)

In this workshop the participants will learn the foundations of the Investigative Science Learning Environment approach (ISLE) to teaching and learning physics and how to use this approach to help students invent the concepts of energy, work, and energy conservation. Specifically, we will focus on the idea of a system and a bar charts as a representation of work-energy processes. The ISLE approach is a scaffolded inquiry approach that helps students learn physics by engaging them in the processes that mirror scientific practice. The students, working in groups, start by observing physical phenomena, identifying patterns, and devising conceptual and quantitative models. Then they design experiments to test the models trying to rule them out. Finally, the students apply the models that were not ruled out by the testing experiments for practical purposes.

Speakers: Eugenia Etkina, Gorazd Planinsic

Energy_Workshop activities.pdf

ISLE resources.pdf

10:00 Fika

10:20 Föreläsning "Joniserande strålning i medicinens tjänst för diagnostik och terapi" (Fysicum K404)

Michael Ljungberg,
Professor och avdelningsföreståndare för Medicinsk strålningsfysik, Lund

Speaker: Michael Ljungberg

Fysikdagarna2022_handouts.pdf

10:30 → 12:00 Plenary session: SFS annual meeting, Fysikum, Sal A (L317)

11:30 Oseenmedaljen 2022: Modellera väteabsorption i en legering

Speaker: Magnus Rahm

Magnus Rahm, 2022 års mottagare av Oseenmedaljen

MagnusRahm.pdf

13:00 → 15:00 Parallel session: Visit to ESS (Please mail susanne.tegler@gmail.com before Thursday 12:00 if you would like to come. Maximum 12 participants.)