Experimental Particle Physics - Science topic

A search for the very rare $$B^{*0}\rightarrow \mu ^+\mu ^-$$ B ∗ 0 → μ + μ - and $$B_{s}^{*0}\rightarrow \mu ^+\mu ^-$$ B s ∗ 0 → μ + μ - decays is conducted by analysing the $$B_c^+\rightarrow \pi ^+\mu ^+\mu ^-$$ B c + → π + μ + μ - process. The analysis uses proton-proton collision data collected with the LHCb detector between 2011 and 2018, co...

Deep learning techniques have evolved rapidly in recent years, significantly impacting various scientific fields, including experimental particle physics. To effectively leverage the latest developments in computer science for particle physics, a strengthened collaboration between computer scientists and physicists is essential. As all machine lear...

The very high luminosity run foreseen at the Z -pole for the FCC-ee will allow the detection in Z decays of new particles with very low couplings to the Standard Model. These particles can have measurable flight paths before they decay. If the timing and the position of the decay vertex can be measured with high precision, the mass of such particle...

A bstract The first full amplitude analysis of B ⁺ → ψ (2 S ) K ⁺ π ⁺ π ⁻ decays is performed using proton-proton collision data corresponding to an integrated luminosity of 9 fb ⁻¹ recorded with the LHCb detector. The rich K ⁺ π ⁺ π ⁻ spectrum is studied and the branching fractions of the resonant substructure associated with the prominent K 1 (12...

AMoRE-II aims to search for neutrinoless double beta decay ( $$0\nu \beta \beta $$ 0 ν β β ) with an array of 423 $$\hbox {Li}_2^{100}\hbox {MoO}_4$$ Li 2 100 MoO 4 crystals operating in the cryogenic system as the main phase of the Advanced Molybdenum-based Rare process Experiment (AMoRE). AMoRE has been planned to operate in three phases: AMoRE-p...

Charged-particle trajectories are usually reconstructed with the LHCb detector using combined information from the tracking devices placed upstream and downstream of the 4 T m dipole magnet. Trajectories reconstructed using only information from the tracker downstream of the dipole magnet, which are referred to as T tracks, have not been used for p...

In this work, we address the question of how to enhance signal-agnostic searches by leveraging multiple testing strategies. Specifically, we consider hypothesis tests relying on machine learning, where model selection can introduce a bias towards specific families of new physics signals. Focusing on the New Physics Learning Machine, a methodology t...

A bstract The inclusive jet cross section is measured as a function of jet transverse momentum p T and rapidity y . The measurement is performed using proton-proton collision data at $$ \sqrt{s} $$ s = 5 . 02 TeV, recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 27.4 pb − 1 . The jets are reconstructed with th...

Self-assembled configurations are versatile for applications in which liquid-mediated phenomena are employed to ensure that static or mild physical interactions between assembling blocks take advantage of local energy minima. For granular materials, however, a particle’s momentum in air leads to random collisions and the formation of disordered pha...

Properties of the underlying-event in pp interactions are investigated primarily via the strange hadrons $$K_{S}^{0}$$ K S 0 , $$\Lambda $$ Λ and $$\bar{\Lambda }$$ Λ ¯ , as reconstructed using the ATLAS detector at the LHC in minimum-bias pp collision data at $$\sqrt{s} = 13$$ s = 13 TeV. The hadrons are reconstructed via the identification of the...

Magnetorheological (MR) fluids can be utilized in one of the fundamental operating modes of which the gradient pinch mode has been the least explored. In this unique mode non-uniform magnetic field distributions are taken advantage of to develop a so-called Venturi-like contraction in MR fluids. By adequately directing magnetic flux the material ca...

A bstract We present an analysis of the sensitivity of current and future LHC searches for new spin-0 particles in top–anti-top-quark $$ \left(t\overline{t}\right) $$ t t ¯ final states, focusing on generic axion-like particles (ALPs) that are coupled to top quarks and gluons. As a first step, we derive new limits on the effective ALP Lagrangian in...

The ATLAS tile calorimeter (TileCal) is the hadronic sampling calorimeter covering the central region of the ATLAS detector at the Large Hadron Collider (LHC). This paper gives an overview of the calorimeter’s operation and performance during the years 2015–2018 (Run 2). In this period, ATLAS collected proton–proton collision data at a centre-of-ma...

An Erratum to this paper has been published: https://doi.org/10.1134/S1062873824110078

A bstract We consider a class of singlet scalar extensions of the Standard Model of particle physics in which the scalar couples only to off-shell states. As a result, low-order tree-level processes involving the singlet scalar vanish, providing a unique phenomenology that may allow to evade existing constraints on new singlet scalar fields. We des...

A bstract The results of a model-independent search for the pair production of new bosons within a mass range of 0 . 21 < m < 60 GeV, are presented. This study utilizes events with a four-muon final state. We use two data sets, comprising 41 . 5 fb − 1 and 59 . 7 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV, recorded in 2017 and...

A bstract In this paper, we calculate the resummed jet mass distribution up to next-to-leading logarithmic accuracy for jets defined with the trimming groomer in Z +jet events at the LHC. We compute at fixed order and to all orders the large logarithms, both in the jet mass and z cut trimming variable, including non-global and clustering logarithms...

Proton–proton collision data recorded by the ATLAS detector in 2011, at a centre-of-mass energy of 7 TeV, have been used for an improved determination of the W -boson mass and a first measurement of the W -boson width at the LHC. Recent fits to the proton parton distribution functions are incorporated in the measurement procedure and an improved st...

We investigate the structure of the minimal left-right symmetric model that enables precise predictions in the gauge, scalar and neutrino sector. We revisit the complete set of mass spectra and mixings for the charged and neutral gauge bosons, would-be-Goldstones and gauge fixing, together with the ghost Lagrangian. In the scalar sector, we analyti...

Raoul Gatto and Bruno Touschek’s collaboration in the establishment of electron–positron colliders as a fundamental discovery tool in particle physics will be illustrated. In particular, we will tell the little-known story of how Gatto and Touschek’s pioneering visions combined to provide the theoretical foundation for AdA, the first matter–antimat...

A bstract S herpa is a general-purpose Monte Carlo event generator for the simulation of particle collisions in high-energy collider experiments. We summarise new developments, essential features, and ongoing improvements within the S herpa 3 release series. Physics improvements include higher-order electroweak corrections, simulations of photoprod...

A bstract This paper presents a search for supersymmetric particles in models with highly compressed mass spectra, in events consistent with being produced through vector boson fusion. The search uses 140 fb − 1 of proton-proton collision data at $$ \sqrt{s} $$ s = 13 TeV collected by the ATLAS experiment at the Large Hadron Collider. Events contai...

A bstract The sensitivity of electron EDM experiments has been increasing at a rapid pace, and could yield indications of new physics in the coming decade. An intriguing possibility is that an EDM signal could be generated by new, electroweak-charged particles at the TeV scale that couple to the Higgs and contribute to the electron EDM at two-loop...

A bstract This paper reports a search for a light CP-odd scalar resonance with a mass of 20 GeV to 90 GeV in 13 TeV proton-proton collision data with an integrated luminosity of 140 fb − 1 collected with the ATLAS detector at the Large Hadron Collider. The analysis assumes the resonance is produced via gluon-gluon fusion and decays into a τ ⁺ τ − p...

A bstract Signal-agnostic data exploration based on machine learning could unveil very subtle statistical deviations of collider data from the expected Standard Model of particle physics. The beneficial impact of a large training sample on machine learning solutions motivates the exploration of increasingly large and inclusive samples of acquired d...

A bstract Searches for anomalous neutral triple gauge boson couplings (NTGCs) provide important tests for the gauge structure of the standard model. At the LHC, NTGCs are searched for via the process pp → ZZ → 4 l , where the two Z -bosons are on-shell. In this paper, we discuss how the same process can occur through tree-level diagrams just adding...

We investigate the impact of incorporating vector-like leptons into the Standard Model, aiming to address longstanding puzzles related to the anomalous magnetic moments of the muon and electron while maintaining consistency with neutrino masses and mixings. We find that among the various representations of vector-like leptons permitted by the Stand...

High-energy nuclear collisions encompass three key stages: the structure of the colliding nuclei, informed by low-energy nuclear physics, the initial condition , leading to the formation of quark–gluon plasma (QGP), and the hydrodynamic expansion and hadronization of the QGP, leading to final-state hadron distributions that are observed experimenta...

A bstract This study investigates the precision measurement of the CKM matrix element | V cb | through semileptonic WW events at future Higgs factories, i.e., FCC-ee, ILC, C ³ , and CEPC. We use full detector simulation to generate the WW → ℓνcb signal events and various backgrounds at $$ \sqrt{s} $$ s = 240 GeV with unpolarized beams. The relative...

A bstract The rare electromagnetic J/ψ → μ ⁺ μ − μ ⁺ μ − decay is observed with a significance greatly exceeding the discovery threshold, using proton-proton collision data collected by the LHCb experiment during 2016–2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5 . 4 fb − 1 . The rate of this decay is mea...

A bstract As the partons in a high energy jet propagate through the droplet of quark-gluon plasma (QGP) produced in a heavy-ion collision they lose energy to, kick, and are kicked by the medium. The resulting modifications to the parton shower encode information about the microscopic nature of QGP. A direct consequence, however, is that the momentu...

Charmonium production cross-section in proton–proton collisions is measured at the centre-of-mass energy $$\sqrt{s}=13\,\textrm{TeV}$$ s = 13 TeV using decays to $$p\bar{p}$$ p p ¯ final state. The study is performed using a data sample corresponding to an integrated luminosity of $$2.2\,\textrm{fb}^{-1}$$ 2.2 fb - 1 collected in 2018 with the $$\t...

Neutral current Drell–Yan (DY) lepton-pair production is considered to study Z -boson quark couplings. Using the open-source fit platform , we investigate the impact of high-statistics measurements of the neutral current DY (NCDY) forward–backward asymmetry $$A_{\textrm{FB}}$$ A FB near the weak boson mass scale in the present and forthcoming stage...

The CONUS experiment aims to detect coherent elastic neutrino-nucleus scattering (CE $$\nu $$ ν NS) of reactor antineutrinos on germanium nuclei in the fully coherent regime, continuing on this way the CONUS physics program started at the Brokdorf nuclear power plant, Germany. The CONUS setup is installed in the nuclear power plant in Leibstadt, Sw...

A bstract We study the production of three electroweak gauge bosons at the LHC, in the effective field theory of the standard model, at dimension six and next-to-leading order in QCD. We present results for inclusive cross-sections and differential distributions, finding that these QCD corrections are large, often vary across the phase-space and no...

The Large Hadron Collider (LHC), the world’s largest and most powerful particle accelerator, has been a pivotal tool in advancing our understanding of fundamental physics. By colliding heavy ions, such as lead ions, the LHC recreates conditions similar to those just after the Big Bang. This allows scientists to study the quark–gluon plasma (QGP), a...

A bstract During the 2015–2018 data-taking period, the Large Hadron Collider delivered proton-proton bunch crossings at a centre-of-mass energy of 13 TeV to the ATLAS experiment at a rate of roughly 30 MHz, where each bunch crossing contained an average of 34 independent inelastic proton-proton collisions. The ATLAS trigger system selected roughly...

A bstract Using pp collision data at $$ \sqrt{s} $$ s = 13 TeV, recorded by the LHCb experiment between 2016 and 2018 and corresponding to an integrated luminosity of 5 . 4 fb − 1 , the forward-backward asymmetry in the pp → Z/γ * → μ ⁺ μ − process is measured. The measurement is carried out in ten intervals of the difference between the muon pseud...

We revisit an economical model for the $$g-2$$ g - 2 anomaly featuring a vector-like charged fermion, a scalar doublet and a scalar singlet in the light of new results from Fermilab. The phenomenological implications for lepton-flavor universality, Higgs decays, and charged lepton-flavor violating decays are discussed in detail.

A bstract A measurement is performed of Higgs bosons produced with high transverse momentum ( p T ) via vector boson or gluon fusion in proton-proton collisions. The result is based on a data set with a center-of-mass energy of 13 TeV collected in 2016–2018 with the CMS detector at the LHC and corresponds to an integrated luminosity of 138 fb − 1 ....

In the present work, we propose to explore the productions of the bottom and bottom-strange mesons in the high-energy pion and kaon-induced reactions on a proton target. The cross sections are evaluated with an effective Lagrangian constructed by the heavy-quark limit and chiral symmetry. Our estimations show that at $$P_\pi =80$$ P π = 80 GeV, the...

A bstract The Deep Underground Neutrino Experiment (DUNE) is a leading experiment in neutrino physics which is presently under construction. DUNE aims to measure the yet unknown parameters in the three flavor oscillation case which includes discovery of leptonic CP violation, determination of the neutrino mass hierarchy and measuring the octant of...

A bstract The production cross sections of D ⁰ , D ⁺ , and $$ {\Lambda}_{\textrm{c}}^{+} $$ Λ c + hadrons originating from beauty-hadron decays (i.e. non-prompt) were measured for the first time at midrapidity in proton–lead (p–Pb) collisions at the center-of-mass energy per nucleon pair of $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 5 . 02 TeV. Nuclear mo...

In the paper, we discuss the development of the multigap resistive plate chamber time-of-flight (TOF) technology and the production of the solenoidal tracker at RHIC (STAR) TOF detector in China at the beginning of the twenty-first century. Subsequently, recent experimental results from the first beam energy scan program (BES-I) at the Relativistic...

The most recent searches by the ATLAS and CMS Collaborations in final states with soft leptons and missing transverse energy show mild excesses predominantly associated with dilepton invariant masses of about $$10{-}20$$ 10 - 20 GeV, which can result from decays of electroweakinos that are heavier than the lightest neutralino by $$\mathcal {O}(10)$...

A bstract A search is presented for new particles produced in proton-proton collisions at a centre-of-mass energy of 13 TeV that result in final states comprising a massive vector ( W or Z ) boson that decays hadronically and large missing transverse momentum. The data sample was collected with the ATLAS experiment at the Large Hadron Collider from...

A bstract We present theoretical predictions for observables in inclusive $$ \overline{B}\to {X}_s{\ell}^{+}{\ell}^{-} $$ B ¯ → X s ℓ + ℓ − suitable for measurements at hadron colliders through a sum-over-exclusive approach. At low q ² we calculate the branching ratio and three angular observables. At high q ² we provide the branching ratio and the...

The M onument experiment measures ordinary muon capture (OMC) on isotopes relevant for neutrinoless double-beta ( $$0\nu \beta \beta $$ 0 ν β β ) decay and nuclear astrophysics. OMC is a particularly attractive tool for improving the theoretical description of $$0\nu \beta \beta $$ 0 ν β β decay. It involves similar momentum transfers and allows te...

A bstract This paper reports the observation of top-quark pair production in proton-lead collisions in the ATLAS experiment at the Large Hadron Collider. The measurement is performed using 165 nb − 1 of p +Pb data collected at $$ \sqrt{s_{\textrm{NN}}} $$ s NN = 8 . 16 TeV in 2016. Events are categorised in two analysis channels, consisting of eith...

In a simplified model including an exotic vector-like X -quark (VLQ- X ) with electric charge 5/3, we investigate the process $$e^{+}p \rightarrow \bar{\nu }_{e}X+\bar{\nu }_{e}X\bar{t}$$ e + p → ν ¯ e X + ν ¯ e X t ¯ induced by the couplings between the VLQ- X and the first- and third-generation quarks at the future ep colliders. We further explor...

We perform a detailed phenomenological study of high-energy neutrino deep inelastic scattering (DIS) focused on LHC far-forward experiments such as FASER $$\nu $$ ν and SND@LHC. To this aim, we parametrise the neutrino fluxes reaching these LHC far-forward experiments in terms of ‘neutrino PDFs’ encoding their energy and rapidity dependence by mean...

A bstract Measurements of the Higgs boson production times decay rates and differential cross-sections have recently been performed by the ATLAS experiment in several decay channels using up to 139 fb − 1 of proton-proton collision data at $$ \sqrt{s} $$ s = 13 TeV recorded at the Large Hadron Collider. This paper presents multiple interpretations...

The global spin alignment of vector mesons has been observed by the STAR collaboration at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL). It provides a unique opportunity to probe the correlation between the polarized quark and antiquark in the strongly coupled quark-gluon plasma (sQGP) produced in relativistic h...

A bstract Using e ⁺ e − collision data collected by the BESIII detector at BEPCII corresponding to an integrated luminosity of 30 fb − 1 , we measure Born cross sections and effective form factors for the process $$ {e}^{+}{e}^{-}\to {\Xi}^0{\overline{\Xi}}^0 $$ e + e − → Ξ 0 Ξ ¯ 0 at forty-five center-of-mass energies between 3.51 and 4.95 GeV. Th...

A bstract We investigate the collinear limit of the energy-energy correlator (EEC) in a heavy-ion context. First, we revisit the leading-logarithmic (LL) resummation of this observable in vacuum following a diagrammatic approach. We argue that this route allows to naturally incorporate medium-induced effects into the all-orders structure systematic...

A bstract A search for neutral long-lived particles (LLPs) decaying in the ATLAS hadronic calorimeter using 140 fb − 1 of proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV delivered by the LHC is presented. The analysis is composed of three channels. The first targets pair-produced LLPs, where at least one LLP is produced with sufficiently low...

In this work, we investigate a new class of transverse momentum dependent functions (TMDs) as known as align-spin (AS) functions, employing the framework of twisted quark states. We reveal that these twisted (vortex) quark states serve as effective tools for the study of TMDs, thereby facilitating a comprehensive analysis of AS-functions. The propo...

A bstract Heavy flavour production in proton-proton (pp) collisions provides insights into the fundamental properties of Quantum Chromodynamics (QCD). Beauty hadron production measurements are widely performed through indirect approaches based on their inclusive decay modes. A Bayesian unfolding data-driven analysis of the ALICE and LHCb data was p...

A bstract We project the reach of future lepton colliders for measuring CKM elements from direct observations of W decays. We focus our attention to | V cs | and | V cb | determinations, using FCC-ee as case study. We employ state-of-the-art jet flavor taggers to obtain the projected sensitivity, and scan over tagger performances to show their effe...

First results on the polarization of $$\Lambda $$ hyperons inclusively produced on 26.5-GeV/ c $${{K}^{ - }}$$ and $${{\pi }^{ - }}$$ beams are presented. The measurements were carried out using the SPASCHARM setup at the U-70 accelerator facility (Protvino, Russia) on nuclear targets in 2021 and 2022. The polarization of an $$\Lambda $$ hyperon on...

A bstract The effective lifetime of the $$ {\textrm{B}}_{\textrm{s}}^0 $$ B s 0 meson in the decay $$ {\textrm{B}}_{\textrm{s}}^0\to \textrm{J}/{\uppsi \textrm{K}}_{\textrm{S}}^0 $$ B s 0 → J / ψK S 0 is measured using data collected during 2016–2018 with the CMS detector in $$ \sqrt{s} $$ s = 13 TeV proton-proton collisions at the LHC, correspondi...

A bstract Extensions of the Standard Model with masses at or below the GeV scale are motivated by searches for dark matter and precision measurements in the quark and lepton flavour sectors, including that of the muon anomalous magnetic moment. An excellent experimental environment to test such light new physics is given by the Belle II experiment,...

This paper describes measurements of the transverse momentum spectra of W and Z bosons produced in proton–proton collisions at centre-of-mass energies of $$\sqrt{s}=5.02$$ s = 5.02 TeV and $$\sqrt{s}=13$$ s = 13 TeV with the ATLAS experiment at the Large Hadron Collider. Measurements are performed in the electron and muon channels, $$W\rightarrow \...

A bstract Transverse momentum p T spectra and anisotropic flow distributions are studied for charmonia and charmed hadrons produced in Pb-Pb collisions and measured with the ALICE detector at the CERN Large Hadron Collider (LHC). The investigations are performed within the framework of the Statistical Hadronization Model with the transverse dynamic...

In this paper, we study the discovery potential of a Vector-Like B quark (VLB) via the process $$pp \rightarrow B(\rightarrow bZ)j\rightarrow b(Z \rightarrow \nu _l\bar{\nu _l})j$$ p p → B ( → b Z ) j → b ( Z → ν l ν l ¯ ) j at the Large Hadron Collider (LHC) with $$\sqrt{s}=14$$ s = 14 TeV. In the framework of a simplified model, we perform a scan...

A bstract A muon collider represents a promising candidate for the next generation of particle physics experiments after the expected end of LHC operations in the early 2040s. Rare or hard-to-detect processes at the LHC, such as the production of multiple gauge bosons, become accessible at a TeV muon collider. We present here the prospects of detec...

A bstract The $$ \mathcal{CP} $$ CP structure of the Higgs boson is a fundamental property which has not yet been constrained with high precision. $$ \mathcal{CP} $$ CP violation in the Yukawa coupling between the Higgs boson and top quark pair can be probed directly at the Large Hadron Collider by measuring top-quark-associated Higgs production. M...

A bstract New low-mass particles with very small couplings to standard model particles that travel significant distances before decaying are interesting candidates to address some of the most intriguing questions of modern physics. In this paper, I propose to extend the LHC’s research program by installing a gaseous fixed target referred to as SHIF...

These lectures were presented at the 2024 QCD Masterclass in Saint-Jacut-de-la-Mer, France. They introduce and review fundamental theorems and principles of machine learning within the context of collider particle physics, focused on application to jet identification and discrimination. Numerous examples of binary discrimination in jet physics are...