The 15th International Workshop on Tau Lepton Physics

24 Sept 2018, 00:00 → 28 Sept 2018, 15:06 Europe/Amsterdam

Vondelkerk, Amsterdam

Cristina Galea (Nikhef National institute for subatomic physics (NL)), Olga Igonkina (Nikhef National institute for subatomic physics (NL))

This is the fifteenth workshop of TAU series on physics of the tau lepton, it’s neutrino, and related processes. The goal of the workshop is to get theorists and experimentalists together to discuss recent progress in the field. New results from high energy machines (e.g LHC experiments: ATLAS, CMS, LHCb), low energy machines (BES-III and other) and B-factories (including Belle-2) will be presented as well as recent results from g-2 and neutrino oscillation experiments. The program also includes related subjects such as hadron cross section measurement at e+e- colliders, lepton universality puzzles in meson decays, searches for Lepton Flavour Violation in τ and μ decays and review talks on the future experiments.

 

Format of the conference:

The program will consist of plenary talks only. Tentative schedule is from Monday lunch time till Friday lunch time. Additionally, there will be a poster session on Monday evening with posters remaining in main room for the full duration of the conference.

 

Venue:

The conference will take place in Vondelkerk, in the center of Amsterdam

 

Conference fee:
The conference fee includes coffee breaks,  the welcome reception, the dinner and the social program. The fee is 225€. The online version of proceedings will be free of charge, and the printed version is 25€.  Accompanying persons are cordially invited to join the conference dinner (60€).

 

Proceedings

We are please to announce that the proceedings for Tau2018 are now available at SciPost.

 

 

Conference Poster

Tau2018LatexTemplate.tar.gz

Tau2018LatexTemplate.zip

Tau2018ProceedingGuideline.pdf

Monday, 24 September

12:00 → 13:00 Registration

13:00 → 13:30 Session: Welcome

13:00 Welcome

Speaker: Stan Bentvelsen (Nikhef National institute for subatomic physics (NL))

13:20 Organisation issues

Speaker: Olga Igonkina (Nikhef National institute for subatomic physics (NL))

Intro.pdf

13:30 → 15:00 Session: Tau properties - I

Convener: Yuping Guo

13:30 Report from the HFLAV group

Speaker: Alberto Lusiani (INFN)

lusiani-tau18.pdf

14:00 Latest Belle results on tau decays

We firstly measure the branching fraction for tau -> pi e+e- nu and pi
mu+mu- nu. Though these decays are allowed by the standard model, they
have never been measured because they are expected to have a small
branching fraction. Belle's largest tau data sample makes us to expect
to measure these decays with a high sensitivity. In this presentation,
we show the result of measurement of branching fraction of these decays
using Belle's full data sample. We also discuss the result with the
hadron physics model prediction, which has been published recently.

Speaker: Yifan Jin (The University of Tokyo)

Tau2018YifanJin.pdf

14:20 Measurement of the branching fractions B(tau -> K npi0 nu), n=0,1,2,3, and B(tau -> pi npi0 nu), n=3,4

We report the measurements of the branching fractions of the decay B(tau -> K npi0 nu), n=0,1,2,3, and B(tau -> pi npi0 nu), n=3,4 excluding the contributions that proceed through the decay of intermediate K0 and \eta mesons. The measurements are based on a data sample of 435 million tau pairs produced in e+e- collisions at and near the Y(4s) peak and collected with the BaBar detector in 1999--2008.
These measurements are substantial improvements of previous measurements and B(tau -> pi 4pi0 nu) is measured for the first time.

Speaker: Thomas Lueck (University of Pisa)

tau2018_thomasLueck.pdf

14:40 Prospects for τ lepton physics at Belle II

The Belle II experiment is a substantial upgrade of the Belle detector and will operate at the SuperKEKB energy-asymmetric e+e− collider. The accelerator has already successfully completed the first phase of commissioning in 2016 and first electron positron collisions in Belle II are expected for April 2018. The design luminosity of SuperKEKB is 8×1035 cm−2s−1 and the Belle II experiment aims to record 50 ab−1 of data, a factor of 50 more than the Belle experiment. Belle II broad programme of τ physics, in particular in searches of lepton flavor and lepton number violations (LFV and LNV), benefiting from the large cross section of the pairwise τ lepton production in e+e−collisions. We expect that after 5 years of data taking, Belle II will be able to reduce the upper limits on LF and LN violating τ decays by an order of magnitude. Any experimental observation of LFV or LNV in τ decays constitutes an unambiguous sign of physics beyond the Standard Model, offering the opportunity to probe the underlying New Physics. In this talk we will review the τ lepton physics program of Belle II.

Speaker: Michel Hernandez Villanueva (Cinvestav)

MVillanueva Tau-Workshop-2018.pdf

15:00 → 15:30 Coffee or lunch break

15:00 Coffee break

15:30 → 18:10 Session: Tau properties - II

Convener: Matthias Jamin

15:30 Tau mass measurement at BESIII

In order to obtain the most accurate mass of tau lepton using a limited amount of data at BESIII, we optimized the position and luminosity distribution of each energy point. Beam energy measurement system was built at BEPCII for minimizing the system error caused by energy uncertainty. About 140 pb-1 tau mass scan data was acquired in April this year, and preliminary measurement results is presented in this talk.

Speaker: Jianyong Zhang (IHEP, CAS)

tau2018_zhangjy-v1.pdf

15:50 Implications of tau data for CP violation in K decays

In the chiral limit, the D = 6 contribution of the Operator Product Expansion (OPE) of the V-A correlator of quark currents only depends on two vacuum condensates, which can be related with the electroweak penguin contributions of K->pipi processes, keys for a better understanding of CP violation in kaons. We use those relations to obtain those matrix elements between hadrons using the ALEPH spectral function.

Speaker: Antonio Rodríguez-Sánchez

tau2018_Rodriguez-Sanchez.pdf

16:10 The status of the inclusive tau determination of V_us

I review the current status of determinations of V_us using inclusive hadronic tau decay data, focusing on (1) recent work establishing theoretical systematic issues with the conventional determination based on flavor-breaking finite-energy sum rule analyses employing only inclusive strange and non-strange branching fractions as experimental input, (2) an alternate flavor-breaking sum rule implementation which avoids these problems, and (3) a very recent lattice-based analysis of the inclusive strange decay distribution. The latter, in particular, clearly establishes that the V_us implied by inclusive hadronic tau decay data is significantly larger than the results obtained from the conventional sum rule implementation, and, in fact, in good agreement within errors with the expectations of three-family unitarity.

Speaker: Kim Maltman (York University)

tau2018_maltman.pdf

16:30 A no-go theorem for non-standard explanations of the τ→KSπντ CP asymmetry

Speaker: Martin Hoferichter (University of Washington)

tau2018_hoferichter_cirigliiano.pdf

16:50 Non-standard interactions in tau- -> (pi-pi0,pi-eta)nu_tau

Being G-parity suppressed in the SM, tau to eta/eta' pi nu_tau decays can set competitive bounds on non-standard scalar charged current interactions. This question is addressed within an EFT framework, including the most general interactions between SM fields up to dimension six, assuming massless neutrinos (based on JHEP 1712 (2017) 027).

Speaker: Gabriel Lopez Castro (Cinvestav-IPN)

SCC-Amsterdam.pdf

17:10 New Physics bounds from Hadronic Tau decays

I'll discuss the information about New Physics that can be extracted from Hadronic Tau decays, and its interplay with other Electroweak Precision Observables and the complementarity with searches at the LHC.

Speaker: Martin Gonzalez-Alonso (CERN)

tau2018_Gonzalez-Alonso.pdf

17:30 NLO prediction for the decays τ→ℓℓ′ℓ′νν¯ and μ→eeeνν¯

We present the differential decay rates and the branching ratios of the tau and muon decays with internal conversion, τ→ℓℓ′ℓ′νν¯ and μ→eeeνν¯, in the Standard Model at NLO in the on-shell scheme.

These five-body leptonic decays are a tool to study the Lorentz structure of the weak interactions and to test lepton flavor universality. They are also a source of SM background for charged-lepton-flavor-violation searches of the forbidden decays μ→eee and τ→ℓℓ′ℓ′.

Even if the shift in the branching ratios induced by radiative corrections turns out to be small and of order 1% --- mainly due to a running effect of the fine-structure constant α --- locally in the phase space these corrections can reach the 5-10 % level, depending on the applied cuts.

We found for instance that in the phase space region where the neutrino energies are small, and the momenta of the three charged leptons have a similar signature as in the μ→eee and τ→ℓℓ′ℓ′ decays, the NLO corrections decrease the leading-order prediction by about 10-20 %.

Speaker: Matteo Fael (University of Siegen)

faeltau.pdf

17:50 BSM b->s tau+ tau-

Speaker: Bernat Capdevila (IFAE)

capdevila.pdf

18:10 → 21:25 Reception: Reception and poster session

18:36 Limits on the anomalous magnetic and electric dipole moments of the tau-neutrino in pp collisions at the LHC

Speaker: Alejandro Gutierrez-Rodriguez (Universidad Autonoma de Zacatecas)

POSTER-AMSTERDAM-TAU-22-08-2018New.pdf

18:37 Sensitivity on the electromagnetic dipole moments of the τ-lepton at the CLIC

Speaker: Maria de los Angeles Hernandez-Ruiz (San Luis Potosi Aut. University)

Poster_M_Hernandez_Ruiz.pdf

18:38 Study of the e+e- -> pi+pi-pi0pi0pi0, pi+pi-pi0pi0eta reactions via ISR at BaBar

Speaker: Evgeny Solodov (BudkerINP)

Solodov_Tau18.pdf

18:40 On isospin breaking in tau input for (g-2) from Lattice QCD

Speaker: Mattia Bruno (BNL)

tau_2018_poster.pdf

18:43 Search for FCNC decays of a top quark to an up-type quark and the SM Higgs boson in the di-tau final state

Speaker: Boyang Li (Tsinghua University (CN))

15thworkshopPoster.pdf

18:45 Measurement of the spectral function for the τ−→K−KSντ decay in Babar experiment

Speaker: Sergey Serednyakov (BINP Novosibirsk)

Serednyakov_Tau18.pdf

18:46 Search for ultra-high energy neutrinos with the Pierre Auger Observatory

Speaker: Marta Trini

tau2018_trini_poster.pdf

18:47 Searches for lepton flavour violation in decays of the Z boson with the ATLAS detector

Speaker: Terry WS Chan (Nikhef National institute for subatomic physics (NL))

20180924_tau2018_ZLFV_poster.pdf

18:48 Disentangle Neutrino Astronomy by Tau signature

Speaker: Daniele Fargion (Rome University 1 Sapienza and INFN)

18:49 Higher order QCD corrections to hadronic tau decays from Padé approximants

Speaker: Diogo Boito (Universidade de São Paulo)

PosterPade_Final.pdf

18:50 Tau reconstruction at CMS with a focus on high momentum taus

Speaker: Soham Bhattacharya (Tata Inst. of Fundamental Research (IN))

poster.pdf

18:52 Study of Michel parameters in tau decays at Belle

Speaker: Denis Epifanov (BINP)

epifanov_poster_tau18.pdf

18:53 Development of the detectors for the DeeMe experiment

Speaker: Natsuki Teshima (Osaka City University)

TAU2018version5.pdf

18:54 The Rare and Forbidden: Testing Physics Beyond the Standard Model with Mu3e

Speaker: Ann-Kathrin Perrevoort (Nikhef National institute for subatomic physics (NL))

Poster_tau2018_perrevoort.pdf

Tau2018_Perrevoort.pdf

18:55 Tau->3 mu in Run-1 with the ATLAS detector

Speaker: Matteo Bedognetti (Nikhef National institute for subatomic physics (NL))

tau3mu_2018_v6.pdf

18:56 Duality Violations and Tau decay

Speaker: Santiago Peris (Univ. Autonoma de Barcelona)

tau2018-PosterDVs.pdf

18:57 Revisiting τ→3μ in the Standard Model and beyond

Recent improvements of the Large Hadron Collider luminosity and beginning of Belle II experiment will increase sensitivity to τ lepton-flavor violating modes. In particular, it has been claimed that BR(τ→3μ) could be as large as 10−14 in the standard model with Dirac neutrinos. This limit could be reached in the near future with further upgrades to the Large Hadron Collider and Belle II. In this talk we revisit this claim in light of more recent neutrino data. Further, we expand this analysis to the case of Majorana masses.

Speaker: Patrick Blackstone (Indiana University Bloomington)

Tau to 3 mu Amsterdam Poster.pdf

Tuesday, 25 September

08:30 → 10:20 Session: Flavor puzzles

Convener: Gregory Max Ciezarek (CERN)

08:30 Theory status

Speaker: Svjetlana Fajfer (Univ. of Ljubljana and Inst. J. Stefan)

Fajfer-tau2018.pdf

09:00 LFU tests with semitauonic decays at LHCb

In the Standard Model, the three charged leptons are identical copies of each other, apart from mass differences. Experimental tests of this feature in semileptonic decays of b-hadrons are highly sensitive to New Physics particles which preferentially couple to the 2nd and 3rd generations of leptons. This talk will review the latest lepton universality tests in semileptonic b->c transitions at LHCb.

Speaker: Sean Benson (Nikhef National institute for subatomic physics (NL))

TAU-2018-SB_LFNU.pdf

09:20 Exploiting tau polarisation in B -> D* tau nu

Speaker: Susanne Westhoff (Heidelberg University)

westhoff.pdf

09:40 Probing LNU with (semi)leptonic B decays

Speaker: Gilberto Tetlalmatzi-Xolocotzi (Nikhef)

Tau_2018_Gilberto.pdf

10:00 LNU, LNV and LFV at Belle II

Speaker: Ami Rostomyan (DESY)

2018-τ.pdf

10:20 → 10:40 Coffee or lunch break

10:40 → 12:40 Session: Lepton Flavor Violation with taus and muons

Convener: Robert Fleischer (Vrije Universiteit Amsterdam)

10:40 Leptonic LFV theory

Speaker: Adrian Signer (Durham University)

6_tau18-signer.pdf

11:10 LFV and neutrino mass

Speaker: Ana M. Teixeira (LPC Clermont)

7_AMTeixeira.cLFV-numass.TAU2018.pdf

11:40 Meson LFV decays (X->e+mu) in LHCb

Speaker: Maarten Van Veghel (Nikhef National institute for subatomic physics (NL))

talk_tau2018_mvveghel_v1.pdf

12:00 Test lepton flavor universality with (semi)leptonic D decays at BESIII

Using 2.93 fb−1 data taken at s√=3.773 GeV and 3.19~fb−1 data taken at s√=4.178 GeV with the BESIII detector, precision measurements of the branching fractions of D0→K−μ+νμ, D+→K¯0μ+νμ, D0→π−μ+νμ, D+→π0μ+νμ and D+s→μ+νμ are performed.
Combining the known branching fractions of D→K¯e+νe, D→πe+νe and D+s→τ+ντ,
we have tested the lepton flavor universality with D→K¯ℓ+νℓ, D→πℓ+νℓ and D+s→ℓ+νℓ decays.
We have also tested lepton flavor universality in different q2ℓνℓ intervals for D→K¯ℓ+νℓ (ℓ=e or μ).
Besides, hadronic form factor fK+(0), D+s decay constant fD+s, and quark mixing matrix element |Vcs| are also extracted with the most precise accuracies to date.

Speaker: Sifan Zhang (Institute of High Energy Physics Chinese Academy of Sciences)

LFU_at_BESIII.pdf

12:20 L to l(') l+ l- LFV decays in the SM with massive neutrinos

Speaker: Dr Gerardo Hernández Tomé (Cinvestav)

AMSTERDAM-GHT.pdf

12:40 → 14:00 Coffee or lunch break

14:00 → 15:55 Session: Standard Model measurements with taus at the LHC

Convener: Keti Kaadze (Kansas State University (US))

14:00 Hadronic Tau reconstruction and identification performance in ATLAS and CMS

Tau leptons play an important role in many Standard Model and Beyond the Standard Model physics processes that are being investigated at the LHC. This talk details measurements of the performance of the reconstruction and identification of hadronic tau lepton decays by the ATLAS and CMS detectors. The measurements include the performance of the identification, trigger, energy calibration and decay mode classification algorithms for reconstructed tau candidates. The performance of these algorithms is measured using the Run 2 dataset of pp collisions collected at the LHC at a centre-of-mass energy sqrt(s)=13 TeV.

Speaker: Anne-Catherine Le Bihan (Centre National de la Recherche Scientifique (FR))

TAU2018_amsterdam.pdf

14:25 Monte Carlo, fitting, Machine Learning for Tau leptons

Over the last few years, progress in analysis of massively multidimensional distribution was achieved for the broad range of applications in Industry, Science and in particular in domain of High Energy physics. In the talk use of such techniques for Higgs boson parity measurement using its cascade decay into tau leptons and later into 3pi decay modes will be used as an example. The use of weighted event samples was very practical and helped to establish distance between events important for the ML applications.

Convenient for that purpose properties of the Tauola Monte Carlo will be presented. The new version feature interface between Monte Carlo library and hadronic currents to be prepared by phenomenologists and/or experimental physicists at the time of data analysis.

The flexibility in that respect of Monte Carlo programs and of the fitting programs, is of importance as precision of tau decay measurements is usually higher than that of the predictions obtained from theoretical considerations of intermediate energy strong interactions. Good technical arrangements can be helpful for the future studies.

Speaker: Zbigniew Andrzej Was (Polish Academy of Sciences (PL))

Amst18.pdf

14:45 Tau polarization measurement in Z->tautau at LHC

Parity violation in decays of Z bosons leads to tau lepton polarisation. The measurement of the polarisation offers a unique possibility to measure tau lepton couplings and to translate them into a measurement of the effective electroweak mixing angle. Data taken by the CMS experiment are used to perform a measurement of the tau lepton polarisation in the most promising hadronic decay modes. The analysis is based on decay-mode-specific optimal observables discriminating between the two possible longitudinal spin states of tau leptons. The resulting average tau polarisation offers the possibility to estimate the effective electroweak mixing angle taking into account the variation of the polarisation as a function of sqrt(s) and the impact of different quark flavours.

....

Speaker: Benedict Tobias Winter (Albert Ludwigs Universitaet Freiburg (DE))

ATL-COM-PHYS-2018-1368.pdf

15:05 Measurements of Higgs boson decays to leptons with the ATLAS detector

The Higgs boson decays to di-leptons has been studied by the ATLAS Collaboration using pp collisions at the LHC. Recent results on the H-> tau tau final state based on 36fb-1 of data collected at 13 TeV will be shown. In addition searches for the Lepton Flavour Violating Higgs boson decays and for the H-> mu mu final state will also be reported.

Speaker: Lara Katharina Schildgen (University of Bonn (DE))

TAU2018_Schildgen.pdf

15:30 Measurements of Higgs properties with the H->tautau decay at CMS

The latest results on the Higgs boson decaying into a tau pair using data from the CMS experiment are reported. The talk will include the observation of the Higgs boson into a tau pair decays with the Run 2 and Run 1 data, and the more recent analyses targeting the VH and ttH production modes. The decay channel into taus allows also constraining the CP properties of the Higgs boson and first results are presented.

Speaker: Somnath Choudhury (Indian Institute of Science (IN))

TAU_2018_CHOUDHURY.pdf

15:55 → 16:15 Coffee or lunch break

16:20 → 18:45 Session: Beyond Standard Model measurements with taus at LHC - I

Convener: Luca Fiorini (Univ. of Valencia and CSIC (ES))

16:20 Higgs LFV involving taus (theory)

Speaker: Cedric Weiland (IPPP Durham)

Talk_Tau2018.pdf

16:40 Search for lepton flavour violation with the ATLAS detector

Lepton flavor violation (LVF) is a striking signature of potential beyond the Standard Model physics. The search for LFV with the ATLAS detector is reported in searches focusing on the decay of the Higgs boson, the Z boson and of a heavy neutral gauge boson, Z', using pp collisions data with a center of mass energy of 8 TeV and 13 TeV.

Speaker: Brian Le (University of Melbourne (AU))

Brian_LE_v5_Tau2018-18-09-25.pdf

17:00 Search for lepton flavour violation with the CMS detector

The experimental observation of neutrino oscillations proves that neutrinos have mass and Lepton Flavour is not conserved in the neutral sector. This implies that Lepton Flavour non-conservation occurs also in the charged sector through neutrino loops, which, however, are extremely suppressed, well beyond the foreseeable experimental reach. On the other hand, several Beyond the Standard Model scenarios predict charged LFV processes, such as tau->3mu, to have branching fractions at the level of 10^{-10} - 10^{8}, which can be achieved by the current experiment in the near or medium term. We present the search for the LFV tau->3mu decay using tau leptons from B and D mesons, as well as from W bosons, based on the 2016 CMS pp dataset, corresponding to an integrated luminosity of 33.1/fb.

Speaker: Jian Wang (University of Florida (US))

Tau2018_JianWang.pdf

17:20 LHC searches motivated by recent B-anomalies

Speaker: Darius Faroughy (Jozef Stefan Institute)

Faroughy_TAU_2018.pdf

17:40 Leptoquark searches and high mass phenomena with taus at CMS

Several searches for new particles with taus are presented. Leptoquarks that couple strongly to the third generation may explain long-standing anomalies observed in B physics. Searches for both singly and doubly produced leptoquarks have been carried out with LHC run 2 data. In addition, searches for scalar partners of the tau, as predicted in supersymmetric models, for new gauge bosons (W' to tau nu, Z' to tau tau), for additional Higgs bosons, and for other phenomena with taus in the final state are discussed.

Speaker: Klaas Padeken (Vanderbilt University (US))

Padeken Amsterdam Tau 2018.pdf

18:00 Searches for new phenomena with tau leptons in the final state using the ATLAS detector

Many theories beyond the Standard Model predict new phenomena which decay to well isolated, high-pT tau leptons. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results reported here use the pp collision data sample collected in 2015 and 2016 by the ATLAS detector at the LHC with a centre-of-mass energy of 13 TeV.

Speaker: Masahiro Kuze (Tokyo Institute of Technology (JP))

TAU2018_Kuze.pdf

18:20 New physics opportunities in the tau sector

Speaker: AMARJIT Soni (BNL)

7_AMS tau 2018 final.pdf

Wednesday, 26 September

08:30 → 09:30 Session: Beyond Standard Model measurements at the LHC - II

Convener: Cristina Galea (Nikhef National institute for subatomic physics (NL))

08:30 Di-Higgs searches in final states with tau leptons at the LHC

Di-Higgs final states can arise through non-resonant production of two Higgs
bosons and through potential heavy states decaying to two Higgs boson. This
talk presents searches for di-Higgs decays in final states containing two tau
leptons and two b-quarks at the ATLAS and CMS experiments using 13 TeV
collision data from the LHC.

Speaker: Petar Bokan (Uppsala University (SE), Georg-August-Universitaet Goettingen (DE))

DiHiggs_Tau2018_PetarBokan_180926.pdf

08:50 Searches for additional Higgs bosons decaying to tau leptons at the LHC

The searches for additional Higgs bosons decaying to tau leptons in scenarios beyond the standard model will be summarised, from the pp collision data collected by the ATLAS and CMS experiments at LHC Run-2.

Speaker: Claudio Caputo (Universite Catholique de Louvain (UCL) (BE))

2_CCaputo_BSMHiggs_Tau2018.pdf

09:10 SUSY searches with taus at the LHC

The supersymmetric partner of the tau lepton, the stau, is predicted to be relatively light in a range of SUSY models, and may be a key for dark matter.
This talk presents recent CMS and ATLAS results from searches for chargino and neutralino mediated stau, and direct stau pair production.

Speaker: Feng Lyu (Chinese Academy of Sciences (CN))

3_Susy-tau_tau2018-v8.pdf

09:30 → 09:50 Coffee or lunch break

09:50 → 12:15 Session: Neutrino - I

Convener: Vittorio Paolone (University of Pittsburgh)

09:50 Neutrinoless Double Beta Decay Overview

Speaker: Laura Cardani (INFN - National Institute for Nuclear Physics)

2018_TauWorkshop.pdf

Neutrinoless Double Beta Decay Overview

10:20 Neutrinoless Double Beta Decay - Theory and Connection to Tau

Speaker: Vincenzo Cirigliano (Los Alamos National Laboratory)

5_cirigliano.pdf

10:50 Solar Neutrino Physics with Borexino

Borexino is a large solar neutrino detector running at the Laboratori Nazionali del Gran Sasso since 2007. Neutrinos are detected via their interaction with a 300-ton liquid scintillator target, purified to achieve unprecedented levels of radio-purity. Borexino has detected most of the expected solar neutrino spectrum, as well as anti-neutrinos from Earth’s radioactivity and from nuclear reactors with a baseline of ~1,000 km. Recently, neutrinos from the entire pp fusion chain in the Sun have been measured with refined precision using analysis tools that fully exploit our understanding of the detector. Among these, the Beryllium-7 neutrinos are now measured with ~3% precision, which contributes to refining solar models and helps address the solar metallicity problem. These recent results will be presented along with an update on ongoing efforts to measure the last missing tile in the solar neutrino puzzle: CNO neutrinos.

Speaker: Andrea Pocar (University of Massachusetts, Amherst)

20180926-pocar-tau2018.pdf

11:10 KATRIN First Tritium

Speaker: Volker Hannen (University of Münster)

7_hannen_tau2018-compl.pdf

11:30 Sterile neutrinos (including SBND program)

Speaker: Ivan Esteban

Talk_Ivan_Esteban.pdf

11:55 Recent Results from MicroBooNE

MicroBooNE is a 85-ton active mass Liquid Argon Time Projection Chamber (LArTPC) which has been collecting data since 2015 from the Booster Neutrino Beam at Fermilab. LArTPCs are imaging detectors that record neutrino interactions with strong spatial resolution and are among the favored technology for the next generation of neutrino experiments. The main goal of MicroBooNE is to investigate the excess of nu-e-like events at low energy observed by the MiniBooNE experiment. It also has a program of precision measurements of neutrino cross sections on argon, as well as providing important LArTPC R&D for future detectors. In this talk, I will present recent results from MicroBooNE on the detector technology, event reconstruction techniques as well as from neutrino beam data.

Speaker: Wei Tang (University of Tennessee)

9_TAU18_uB_WeiTang.pdf

12:15 → 13:30 Coffee or lunch break

13:30 → 15:00 Session: Neutrino - II

Convener: Paul De Jong (Nikhef National institute for subatomic physics (NL))

13:30 Recent results from reactor antineutrino experiments

The smallest neutrino mixing angle θ_13 has been successfully measured by the disappearance of reactor antineutrinos at RENO, Daya Bay, and Double Chooz. The oscillation frequency is also measured based on energy and baseline dependent disappearance probability of reactor antineutrinos. Recent results find a variation in the observed reactor antineutrino flux as a function of the reactor fuel evolution. In this talk, we present more precisely measured values of θ_13 and dm^2_ee and results on the evolution of observed reactor antineutrino yields.

Speaker: Hyunkwan Seo

TAUP2018_reactor_v1.pdf

13:50 Final results of the OPERA experiment on nu-tau appearance in the CNGS neutrino beam

The OPERA experiment at the Gran Sasso Laboratory was designed to study nu_mu → nu_tau oscillations in appearance mode in the CERN-to-Gran Sasso neutrino beam. We report the final analysis of the full data sample based on looser selection criteria than in previous analyses, and multivariate approach. Oscillation parameters have been determined with a reduced statistical uncertainty, and the discovery of tau neutrino appearance is confirmed with an improved significance level. The measurement of nu_tau CC cross-section was performed, and the direct observation of the nu_tau- lepton number is also reported.

Speaker: Giuliana Galati (Universita e sezione INFN di Napoli (IT))

14:10 Beams T2K, NOvA and resulting picture

Speaker: Pablo Fernandez Menendez (Univ. of Valencia and CSIC (ES))

beamer.pdf

14:35 Cosmic neutrinos: IC, KM3NeT, ANTARES, AUGER

Speaker: Daan van Eijk (WIPAC)

TAU_DaanVanEijk_small.pdf

15:00 → 18:00 Social program: museum excursion

Thursday, 27 September

08:30 → 10:05 Session: g-2 theory

Convener: Mattia Bruno (BNL)

08:30 Introduction

Speaker: William Marciano (Brookhaven)

1_marchiano.pdf

09:15 Hadronic vacuum polarization

Speaker: Christoph Lehner (BNL)

talk-nobackup.pdf

09:40 Hadronic light-by-light

Speaker: Harvey Meyer

3_meyerhTAU18.pdf

10:05 → 10:30 Coffee or lunch break

10:30 → 13:00 Session: g-2 experiments

Convener: Charles Timmermans

10:30 Historical Overview

Speaker: Bradley Lee Roberts (Boston University)

4_BLRoberts-Tau2018-historical-g-2-final.pdf

4_BLRoberts-Tau2018-historical-g-2-final.pptx

11:00 E989 @ FNAL

Speaker: Anna Driutti

5_driutti_GM2FNAL.pdf

11:20 E34 @ KEK

Speaker: Tsutomu Mibe

6_tau2018_mibe_20180927_r1.pdf

11:40 Auxiliary measurements, esp. mumu/mup in Muonium; MuSEUM experiment

Speaker: Shimomura

7_Tau2018.pdf

12:00 Search for the Electric Dipole Moment and anomalous magnetic moment of the tau lepton at tau factories

Precise measurement of the Electric Dipole Moment (EDM) and anomalous magnetic moment (g-2) of particles is an important test of Beyond Standard Model (BSM) physics. It is generally believed that the tau lepton couples more strongly to BSM due to its large mass, and can be searched for at collider experiments. A new method to approximately reconstruct the neutrinos from the hadronic decays of τ−τ+ pairs produced at e−e+ tau factories is proposed. With a matrix element technique, and the estimated 50 ab−1 of data to be delivered by the Belle-II experiment, a tau EDM search with a 1-σ level precision of |dτ|<2.09×10−19 e⋅cm, and g-2 search with |Δaτ|<1.80×10−5 (1.5% of the SM prediction), can be expected. The new precisions can put an upper bound on the heavy mirror neutrino mass, which is complimentary to the direct search at hadron colliders, or a light scalar with mass at O(1 GeV), which can explain the current muon g-2 anomaly as well. The method in this work offers a new opportunity to search for BSM in current and future tau factories with high precision.

Speaker: Xin Chen (Tsinghua University (CN))

Tau2018_talk_v1.pdf

12:20 Experimental input from e+e- machines to hadronic contribution to muon (g-2)

The VEPP-2000 e+e− collider has been operating at BINP (Novosibirsk) from 2010 in the center-of-mass energy range from 0.3 to 2 GeV. The project luminosity of this machine, exploiting the idea of the round beams, has to amount to 1032cm−2s−1. In 2017 experiments at VEPP-2000 were renewed after three year shutdown taken for new intensive positron injection source implementation as well as for upgrade of 1 GeV booster. After this upgrade the luminosity up to 5×1032cm−2s−1 was achieved. Two detectors, CMD-3 and SND, are running at two interaction regions of the VEPP-2000. Each detector collected about 120 pb-1 in the new run. Considerable statistics was taken within an energy range around the nucleon-antinucleon pair production.
Precise study of the hadrons production in e+e− annihilation at low energies provides important information about interactions of light quarks and spectroscopy of their bound states.
Precise measurements of the total hadronic cross section, characterized by the ratio R, is vitally needed for the calculation of the contribution of the hadronic vacuum polarization to the muon anomalous magnetic moment. It should be noted that at present the accuracy of the theoretical calculations of the muon (g-2) via the Standard Model is dominated by the precision of the hadronic contribution while the difference of theoretical and experimental values exceeds three standard deviations.
In this report we will discuss current status and results obtained by the of the CMD-3 experiment.

Speaker: Boris Shwartz (Budker Institute of Nuclear Physics, Novosibirsk)

talk-tau18-3.pdf

12:40 e+e- for g-2 light-by-light

Speaker: Yuping Guo

10_YPGuo-Tau2018.pdf

13:00 → 14:30 Coffee or lunch break

14:30 → 15:30 Session: QCD

Convener: Elisabetta Pallante

14:30 Alpha_s from lattice

Speaker: Stefan Sint (Trinity College Dublin (IE))

tau18.pdf

14:50 The strong coupling from e+e−→ hadrons

We use a new compilation of the hadronic R-ratio from available data for the process e+e−→ hadrons below the charm mass to determine the strong coupling αs, using finite-energy sum rules. Quoting our results at the τ mass to facilitate comparison to the results obtained from similar analyses of hadronic τ-decay data, we find αs(m2τ)=0.298±0.016±0.006 in fixed-order perturbation theory, and αs(m2τ)=0.304±0.018±0.006 in contour-improved perturbation theory, where the first error is statistical, and the second error combines various systematic effects. These values are in good agreement with a recent determination from the OPAL and ALEPH data for hadronic τ decays.

Speaker: Maarten Golterman (San Francisco State University)

2afternoon____tau2018_Golterman.pdf

15:10 Alpha_s from tau data

Speaker: Antonio Pich (IFIC, U. Valencia -.)

3TAU2018_Rtau_pich.pdf

15:30 → 16:00 Coffee or lunch break: Conference picture

16:00 → 18:00 Session: Muon experiments

Convener: Nicolo De Groot (Department of Experimental High Energy Physics)

16:00 General features of LFV experiments with muons

Speaker: Yoshitaka Kuno (Osaka University)

1Tau2018_KUNO.pdf

16:30 The Mu3e Experiment at PSI

Lepton Flavor Violation (LFV) is strongly suppressed in the Standard Model, whilst several models based on {\it new physics} predict observable effects accessible to the new generation of experiments. Mu3e will search for the LFV neutrinoless muon decay μ+→e+e−e+ with a sensitivity down to 10−16 (at 90\% C.L.) using the world most intense continuous muon beam at the Paul Scherrer Institute.

The search for the μ+→e+e−e+ decay requires a large acceptance detector capable of coping with rates of up to 2×109 stopped muons per second with excellent momentum, spacial, and time resolution. The Mu3e detectoris based on thin monolithic active silicon pixel sensors (HV-MAPS) for precise tracking in conjunction with scintillating fibers and tiles coupled to Si-PMs arrays for very precise timing measurements. After an intense R\&D phase, the Mu3e apparatus is under constructions. First data is expected in 2020.

Speaker: Alessandro Bravar (Universite de Geneve (CH))

2Bravar_Tau2018.pdf

16:50 Searching for Muon to electron conversion : The Mu2e experiment at Fermilab

The Mu2e experiment will measure the charged-lepton flavor violating (CLFV) neutrino-less conversion of a negative muon into an electron in the field of a nucleus. Mu2e will improve the previous measurement by four orders of magnitude, reaching a SES (single event sensitivity) of 3×10−17 on the conversion rate. The experiment will reach mass scales of nearly 104 TeV, far beyond the direct reach of colliders. The experiment is sensitive to a wide range of new physics, complementing and extending other CLFV searches.

Mu2e is under design and construction at the Muon Campus of Fermilab; we expect to start taking physics data in 2022 with 3 years of running to achieve our target sensitivity. We will present the physics motivation for Mu2e, the detector design, and the current experimental status.

Speaker: Richard Bonventre (Lawrence Berkeley National Laboratory)

3bonventre_tau2018.pdf

17:10 mu-e conversion experiments in J-PARC

Speaker: Natsuki Teshima (Osaka City University)

teshima_TAU201809_v10.pdf

17:30 MEG final results and progress towards MEG-II

Speaker: Toshiyuki Iwamoto

5iwamoto_tau.pdf

19:00 → 22:00 Dinner

Friday, 28 September

08:30 → 10:00 Session: Future detectors - I

Convener: Kenji Inami (Nagoya university)

08:30 Tau physics at the High Luminosity LHC

Speaker: Emilie Passemar (Indiana University/JLab)

1_EPassemar_HEHL.pdf

08:50 Tau physics at CEPC/ILC

Speaker: Manqi Ruan (Chinese Academy of Sciences (CN))

2_Tau CEPC-ILC v23.pdf

09:10 Tau physics at FCC

Speaker: Mogens Dam (University of Copenhagen (DK))

FCCtau2018.pdf

09:30 GRAND: A Giant Radio Array for Neutrino Detection

Precise detection of cosmogenic ultra-high-energy (UHE) neutrinos, with energy in excess of 108 GeV, will confirm the photo-dissociation of UHE cosmic rays and the identification of the sources of UHE neutrinos will directly point to sources of UHE cosmic rays.

GRAND will look for ντs interacting in rock, thereby creating an UHE τ lepton, which can escape from the rock.The τ decay products will create an air shower that can be detected.

As the flux of these UHE neutrinos is expected to be low, GRAND requires a huge exposure, which is only possible with a cheap and reliable detection method. Our air shower detection is based on the recently proven radio technology. In several steps of development we expect to be able to instrument up to 200,000 km2 for about 150 M euro.

Except for a guaranteed detection of UHE neutrinos, GRAND will be able to investigate many other science topics, including neutrino physics, UHE gamma-ray detection, UHE cosmic ray astronomy and physics with very large statistics, the detection of fast radio bursts and giant radio pulses, and a measurement of the epoch of reionisation.

The R&D and different initial phases of development of GRAND, as well as the physics reach for these research topics will be discussed.

Speaker: Charles Timmermans

4_CTGrand.pdf

10:00 → 10:20 Coffee or lunch break

10:20 → 11:40 Session: Future detectors - II

Convener: Marcus Matthias Morgenstern (Nikhef National institute for subatomic physics (NL))

10:20 Status of the DUNE Experiment

The Deep Underground Neutrino Experiment (DUNE) provides a rich science program with the focus on the neutrino oscillation physics, proton decay studies and Supernova explosions. The high-intensity wide-band neutrino beam will be produced at Fermilab and will be directed to the 40 kt Liquid Argon far detector at the Sanford Underground Research Facility (SURF), 1300 km from Fermilab. One of the most important goals of the experiment is to determine the neutrino mass ordering and the measurement of the CP violating phase. The underground location of the large DUNE far detector and its excellent energy and spatial resolution will allow also conducting non-accelerator physics programs predicted by GUT models, such as nucleon decay or n-nbar oscillations. Moreover, it will be sensitive to measure of the electron neutrino flux from a core-collapse supernova providing valuable information on the mechanism of a supernova. This ambitious project involves worldwide contribution and extensive prototyping and testing program to guarantee that all parts of the technology are fully understood and well tested. Two such prototypes, in both single phase (ProtoDUNE-SP) and dual phase (ProtoDUNE-DP) technologies, are under construction and will be operated at the CERN Neutrino Platform (NP) starting in 2018.

Speaker: Alessandra Tonazzo

1_180928_TAU2018_DUNE.pdf

10:40 Super tau charm factory, HIEPA

Speaker: Guangshun Huang (University of Science and Technology of China (CN))

STCF_tau2018.pdf

11:00 Novosibirsk: tau-charm factory and di-muonium experiment

Speaker: Pavel Piminov (Budker Institute of Nuclear Physics (RU))

3_piminov.pdf

3_piminov.ppt

11:20 SHIP

Speaker: Kyrylo Bondarenko

Bondarenko_SHiP.pdf

11:40 → 12:00 Coffee or lunch break

12:00 → 13:30 Session: Poster presentations and summary talk

Convener: Olga Igonkina (Nikhef National institute for subatomic physics (NL))

12:00 4th place: Search for ultra-high energy neutrinos with the Pierre Auger Observatory

Speaker: Marta Trini

4.pdf

12:10 3rd place: Study of Michel parameters in tau decays at Belle

Speaker: Denis Epifanov (BINP)

3.pdf

12:20 2nd place: The Rare and Forbidden: Testing Physics Beyond the Standard Model with Mu3e

Speaker: Ann-Kathrin Perrevoort (Nikhef National institute for subatomic physics (NL))

2.pdf

12:35 1st place: On isospin breaking in tau input for (g-2) from Lattice QCD

Speaker: Mattia Bruno (BNL)

1.pdf

12:45 Summary talk

Speaker: Simon Eydelman (Budker Institute of Nuclear Physics (RU))

summary_am18.pdf