Publications

Order by: publication date number of citations

• Status and prospects of the JUNO experiment

  Matthias Raphael Stock, on behalf of the JUNO collaboration

  SciPost Phys. Proc. 17, 020 (2025) · published 23 July 2025 | Toggle abstract · pdf

  The Jiangmen Underground Neutrino Observatory (JUNO) is a multi-purpose neutrino experiment currently under construction in China. It is located 52.5 km away from two nuclear power plants in a newly constructed 700-m-deep underground laboratory. JUNO will be the largest liquid scintillator (LS) detector in the world comprising 20 kt of ultra-pure LS filled in an acrylic sphere. Its main goal is to determine the neutrino mass ordering by measuring the energy spectrum of reactor neutrinos with highest accuracy. In addition, JUNO will cover precision measurements of oscillation parameters and several aspects in the field of astroparticle physics. Data taking will start in late 2024.

• The Hyper-Kamiokande experiment: Status and prospect

  Umut Kose, on behalf of Hyper-Kamiokande collaboration

  SciPost Phys. Proc. 17, 019 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Hyper-Kamiokande is the next-generation neutrino observatory, aiming to tackle a broad spectrum of physics programs. These include probing leptonic CP violation through long baseline accelerator neutrino oscillations, determining neutrino mass ordering, potentially discovering the proton decay, and capturing neutrinos from supernova relics, other astrophysical sources, and the sun. As the world's largest underground Cherenkov detector, Hyper-Kamiokande boasts a fiducial volume eight times that of its predecessor, Super-Kamiokande. With 258 kton of ultrapure water as its medium, Hyper-Kamiokande is scheduled to begin its groundbreaking operations in 2027, located in Kamioka, Japan. This proceeding outlines the ambitious physics program of Hyper-Kamiokande, details of the design of the detector, and provides an update on its current status.

  1 citation

• FASER experiment and first results from LHC run 3

  Umut Kose, on behalf of FASER collaboration

  SciPost Phys. Proc. 17, 018 (2025) · published 23 July 2025 | Toggle abstract · pdf

  FASER is designed to search for light, extremely weakly interacting and long-lived beyond standard model particles at the CERN Large Hadron Collider. Such particles, e.g., dark photons, may be produced in the high-energy proton-proton collisions at the ATLAS interaction point and then decay to visible particles in FASER, which is placed 480 m downstream and aligned with the collision axis line-of-sight. The detector covers a previously unexplored range of pseudorapidity larger than 8.8, which allows it to have sensitivity to new physics in the far-forward region. FASER also has a sub-detector called FASER$\nu$, which is specifically designed to detect and investigate high-energy collider neutrino interactions in the TeV regime, extending current cross-section measurements. In this proceeding, the FASER detector and present recent results obtained during LHC Run 3 will be introduced.

• Matter effect in $P_{\mu \tau}$ at long baselines

  Srubabati Goswami, Supriya Pan, Animesh Chatterjee

  SciPost Phys. Proc. 17, 017 (2025) · published 23 July 2025 | Toggle abstract · pdf

  In the simple two-generation case, the probability $P_{\mu \tau}$ is not affected by interactions of neutrinos in matter. But for three-generation case, at baselines of the order of 9000 km, matter effects become important for this channel. This is a genuine three-flavour effect. We study how the presence of non-standard interactions (NSI) alters the $P_{\mu \tau}$ at these baselines. We observe large deviations from the standard matter effect. In particular, we find energies and baselines for which the phases governing the NSIs do not play any role. This may facilitate a better determination of NSI parameters if tau neutrinos can be detected.

• Search for lepton flavour violating decays involving tau leptons in the final state at CMS

  Luca Guzzi

  SciPost Phys. Proc. 17, 016 (2025) · published 23 July 2025 | Toggle abstract · pdf

  In the Standard Model (SM) lepton flavour numbers are approximately conserved at energies accessible to current experiments, where lepton flavour violation is extremely suppressed. The observation of neutrino oscillations, however, proves that neutrinos are massive particles and allows for additional Lepton Flavour Violating (LFV) processes also at low energies. Nevertheless, these processes are predicted with very low branching ratios and are sensitive to new physics effects, which could manifest as an enhancement in the decay probability. Similarly, Lepton Flavour Universality Violating (LFUV) observables allows for the test of the SM and the study of beyond the SM theories. The latest CMS results from the Higgs, B-physics and exotica groups are presented on the search for LFV and LFUV with tau leptons in the final state. The results are based on data collected in proton-proton collisions at the centre-of-mass energy of 13 TeV.

• Searches for new physics that couple with third generation fermions

  Valeria D'Amante, on behalf of the CMS collaboration

  SciPost Phys. Proc. 17, 015 (2025) · published 23 July 2025 | Toggle abstract · pdf

  The $\tau$ lepton, with a mass of $1776.86 ± 0.12$ MeV, is unique in its ability to decay into hadrons and a neutrino. Approximately one-third of $\tau$ decays produce an electron or a muon and two neutrinos, denoted as $\tau_e$ and $\tau_\mu$. The remaining decays, mainly involving hadrons and a tau neutrino, are denoted as $\tau_h$. At the CERN LHC, searches involving $\tau$ leptons are crucial for studying the decay of Higgs bosons to $\tau$ pairs, probing Yukawa couplings, and CP properties of the Higgs. These measurements support Standard Model (SM) tests and searches for Beyond Standard Model (BSM) physics, including new or heavy Higgs bosons, leptoquarks, supersymmetric particles, or gauge bosons. The $\tau$ lepton polarization in Z boson decays is also significant for probing the SM. Despite its potential as a portal to new physics, the $\tau$ lepton's decay products, especially neutrinos and hadrons, make its reconstruction and identification challenging at the LHC. At the CMS experiment, neutrinos contribute to Missing Transverse Energy (MET), and hadronically decaying $\tau$ leptons are often misidentified as jets, complicating the separation of $\tau$-involved processes from background processes.

• Searches for new phenomena in final states with taus using the ATLAS detector

  Giuseppe Carratta

  SciPost Phys. Proc. 17, 014 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Many theories beyond the Standard Model predict new phenomena, such as leptoquarks, vector like leptons, $Z'$ and $W'$ bosons, supersymmetry, new scalars or heavy leptons, in final states with isolated, high-$p_{T}$ taus. Searches for new physics with such signatures, produced either resonantly or non-resonantly, are performed using the ATLAS experiment at the LHC. The most recent results at $\sqrt{s} =$ 13 TeV in proton-proton collision, are presented in this contribution.

• Measurements of Higgs boson properties in decays to two Tau leptons and search for lepton-flavor-violating Higgs boson decays into Tau leptons using the ATLAS detector

  Ömer Oğul Öncel

  SciPost Phys. Proc. 17, 013 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Three analyses exploiting the $H→\tau\tau$ process using 139 fb$^{-1}$ of proton--proton collision data collected at a center-of-mass energy of 13 TeV by the ATLAS detector at the LHC are presented. A measurement of $VH$ production, with $V(=W, Z)→ e\nu/\mu\nu,ee/\mu\mu$ decays, has established the first evidence for this process with an observed (expected) significance of 4.2 (3.6) standard deviations. The second analysis, first of its kind by the ATLAS collaboration, probes CP-invariance if the decay products of the $\tau$ leptons using an angular observable $\phi_\tau$, and measured an observed (expected) value of $\phi_\tau=9 ± 16^\circ (0 ± 28^\circ)$ at 68% confidence level. The last analysis is a search for lepton-flavour-violation in $H→ e\tau/\mu\tau$ decays, where most stringent exclusion limits at 95% confidence level on $H→ e\tau$ branching ratio of 0.2%, is obtained.

• Chiral Belle: e-Beam polarization upgrade of SuperKEKB

  J. Michael Roney

  SciPost Phys. Proc. 17, 012 (2025) · published 23 July 2025 | Toggle abstract · pdf

  Recent R&D work associated with upgrading the SuperKEKB $e^+e^-$ collider with polarized electron beams is presented. The Chiral Belle physics program enables a set of unique precision measurements using the Belle II detector. It includes a set of measurements of $\sin^2\theta_W$ via separate left-right asymmetry ($A_{LR}$) measurements in annihilations to pairs of electrons, muons, taus, charm and b-quarks that yield precisions matching or exceeding those of the current world averages from measurements at the $Z^0$-pole, but at 10GeV, thereby also probing the running of the couplings. Chiral Belle will also probe for new physics via the highest precision measurements of neutral current universality ratios and precision measurements of tau lepton properties, including the tau magnetic moment. After summarizing the physics goals, developments related to provision of the polarized source, the new components of the accelerator lattice that rotate the electron spin from transverse to longitudinal at the interaction point, and polarimetry of the electron beam will be reported.

• Precision $e^-$ beam polarimetry at an $e^+e^-$ B factory using tau-pair events

  Caleb Miller

  SciPost Phys. Proc. 17, 011 (2025) · published 23 July 2025 | Toggle abstract · pdf

  A novel technique for measuring the average beam polarization in $e^+e^-$ collisions, known as Tau Polarimetry, has been developed by the BABAR collaboration. This technique makes use of the relationship between the polarization of the beams, the resulting polarization of the $\tau^+\tau^-$ produced, and the kinematics of the decay products. Using this technique BABAR has measured the average $e^-$ beam polarization of PEP-II to be 0.0034 $± 0.0024_{stat} ± 0.0029_{sys}$. This technique is expected to be used at Belle II after a proposed polarization upgrade as the most precise method with which beam polarization can be determined.