A search is presented for hadronic signatures of beyond the Standard Model (BSM) physics, with an emphasis on signatures of a strongly-coupled hidden dark sector accessed via resonant production of a $Z'$ mediator. The ATLAS experiment dataset collected at the Large Hadron Collider from 2015 to 2018 is used, consisting of proton-proton collisions at $\sqrt{s}$ = 13 TeV and corresponding to an integrated luminosity of 140 fb$^{-1}$. The $Z'$ mediator is considered to decay to two dark quarks, which each hadronize and decay to showers containing both dark and Standard Model particles, producing a topology of interacting and non-interacting particles within a jet known as ``semi-visible". Machine learning methods are used to select these dark showers and reject the dominant background of mismeasured multijet events, including an anomaly detection approach to preserve broad sensitivity to a variety of BSM topologies. A resonance search is performed by fitting the transverse mass spectrum based on a functional form background estimation. No significant excess over the expected background is observed. Results are presented as limits on the production cross section of semi-visible jet signals, parameterized by the fraction of invisible particles in the decay and the $Z'$ mass, and by quantifying the significance of any generic Gaussian-shaped mass peak in the anomaly region.
Acceptance times efficiency weighted yields across the signal grid.
The 95% CL limits on the cross-section $\sigma(pp \rightarrow Z' \rightarrow \chi \chi$) times branching ratio B in fb with all statistical and systematic uncertainties, for the $R_{\text{inv}}=$0.2 signal points.
The 95% CL limits on the cross-section $\sigma(pp \rightarrow Z' \rightarrow \chi \chi$) times branching ratio B in fb with all statistical and systematic uncertainties, for the $R_{\text{inv}}=$0.4 signal points.
Inclusive and differential cross sections for Higgs boson production in proton-proton collisions at a centre-of-mass energy of 13.6 TeV are measured using data collected with the CMS detector at the LHC in 2022, corresponding to an integrated luminosity of 34.7 fb$^{-1}$. Events with the diphoton final state are selected, and the measured inclusive fiducial cross section is $σ_\text{fid}$ = 74 $\pm$ 11 (stat) $^{+5}_{-4}$ (syst) fb, in agreement with the standard model prediction of 67.8 $\pm$ 3.8 fb. Differential cross sections are measured as functions of several observables: the Higgs boson transverse momentum and rapidity, the number of associated jets, and the transverse momentum of the leading jet in the event. Within the uncertainties, the differential cross sections agree with the standard model predictions.
Differential fiducial cross sections for pT of the Higgs boson
Example description
Differential fiducial cross sections for rapidity of the Higgs boson
We present a search for the rare flavor-changing neutral-current decay $B^0 \to K^{\ast 0} \tau^+ \tau^-$ with data collected by the Belle II experiment at the SuperKEKB electron-positron collider. The analysis uses a 365 fb$^{-1}$ data sample recorded at the center-of-mass energy of the $\Upsilon(4S)$ resonance. One of the $B$ mesons produced in the $\Upsilon(4S)\to B^0 \bar{B}^0$ process is fully reconstructed in a hadronic decay mode, while its companion $B$ meson is required to decay into a $K^{\ast 0}$ and two $\tau$ leptons of opposite charge. The $\tau$ leptons are reconstructed in final states with a single electron, muon, charged pion or charged $\rho$ meson, and additional neutrinos. We set an upper limit on the branching ratio of $BR(B^0 \to K^{\ast 0} \tau^+ \tau^-) < 1.8 \times 10^{-3}$ at the 90% confidence level, which is the most stringent constraint reported to date.
- - - - - - - - Overview of HEPData Record - - - - - - - -<br/><br/></ul><b>Post-fit yields:</b><ul><li><a href="159541?version=1&table=Postfit%20yields:%20fit%20variable">Fit variable $\eta(\rm{BDT})$</a></ul><b>Signal $q^{2}$:</b><ul><li><a href="159541?version=1&table=Generated%20$q^2$"> Generated $q^{2}$ distribution </a></ul><b>Signal selection efficiency:</b><ul><li><a href="159541?version=1&table=Selection%20efficiency"> Selection efficieny in signal region </a>
Observed yields and fit results in bins of $\eta(\rm{BDT})$ as obtained by the fit on the four signal categories, corresponding to an integrated luminosity of 365 fb$^{-1}$. The yields are shown for $B^0 \rightarrow K^{\ast 0}\tau\tau$ signal and the two background components ($B\bar{B}$ decays and $q\bar{q}$ continuum).
Distribution of the di-tau invariant mass squared $q^2$ assumed for the generated signal $B^0 \rightarrow K^{\ast 0}\tau\tau$ events.
The first measurement of the dijet transverse momentum balance $x_j$ in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}}$ = 8.16 TeV is presented. The $x_j$ observable, defined as the ratio of the subleading over leading jet transverse momentum in a dijet pair, is used to search for jet quenching effects. The data, corresponding to an integrated luminosity of 174.6 nb$^{-1}$, were collected with the CMS detector in 2016. The $x_j$ distributions and their average values are studied as functions of the charged-particle multiplicity of the events and for various dijet rapidity selections. The latter enables probing hard scattering of partons carrying distinct nucleon momentum fractions $x$ in the proton- and lead-going directions. The former, aided by the high-multiplicity triggers, allows probing for potential jet quenching effects in high-multiplicity events (with up to 400 charged particles), for which collective phenomena consistent with quark-gluon plasma (QGP) droplet formation were previously observed. The ratios of $x_j$ distributions for high- to low-multiplicity events are used to quantify the possible medium effects. These ratios are consistent with simulations of the hard-scattering process that do not include QGP production. These measurements set an upper limit on medium-induced energy loss of the subleading jet of 1.26% of its transverse momentum at the 90% confidence level in high multiplicity pPb events.
The unfolded dijet balance distribution, $(1/N_{dijet})(dN_{dijet}/dx_{j})$, as function of $x_{j}$ for the $10-60$, $60-120$, $120-185$, $185-250$ and $250-400$ multiplicity ranges with both jets at the midrapidity regions.
The unfolded dijet balance distribution, $(1/N_{dijet})(dN_{dijet}/dx_{j})$, as function of $x_{j}$ for the $10-60$, $60-120$, $120-185$, $185-250$ and $250-400$ multiplicity ranges with leading and subleading jets at midrapidity and forward regions, respectively.
The unfolded dijet balance distribution, $(1/N_{dijet})(dN_{dijet}/dx_{j})$, as function of $x_{j}$ for the $10-60$, $60-120$, $120-185$, $185-250$ and $250-400$ multiplicity ranges with leading and subleading jets at midrapidity and backward regions, respectively.
The pseudorapidity distribution of charged hadrons produced in Au+Au collisions at a center-of-mass energy of $\sqrt{s_\mathrm{NN}} = 200$ GeV is measured using data collected by the sPHENIX detector. Charged hadron yields are extracted by counting cluster pairs in the inner and outer layers of the Intermediate Silicon Tracker, with corrections applied for detector acceptance, reconstruction efficiency, combinatorial pairs, and contributions from secondary decays. The measured distributions cover $|\eta| < 1.1$ across various centralities, and the average pseudorapidity density of charged hadrons at mid-rapidity is compared to predictions from Monte Carlo heavy-ion event generators. This result, featuring full azimuthal coverage at mid-rapidity, is consistent with previous experimental measurements at the Relativistic Heavy Ion Collider, thereby supporting the broader sPHENIX physics program.
Nch, Npart, and Nch/(Npart/2) values in Table 4, presented in Figure 6.
Nch as a function of $\eta$, presented in Figure 5.
This paper reports measurements of the transverse energy per unit pseudorapidity ($dE_{T}/dη$) produced in Au+Au collisions at $\sqrt{s_{NN}} = 200$ GeV, performed with the sPHENIX detector at the Relativistic Heavy Ion Collider (RHIC). The results cover the pseudorapidity range $\left|η\right| < 1.1$ and constitute the first such measurement performed using a hadronic calorimeter at RHIC. Measurements of $dE_{T}/dη$ are presented for a range of centrality intervals and the average $dE_{T}/dη$ as a function of the number of participating nucleons, $N_{\mathrm{part}}$, is compared to a variety of Monte Carlo heavy-ion event generators. The results are in agreement with previous measurements at RHIC, and feature an improved granularity in $η$ and improved precision in low-$N_{\mathrm{part}}$ events.
An example of a reconstructed EMCal di-cluster invariant mass distribution, similar to those used for in situ EMCal tower calibrations. The distributions are made from EMCal cluster pairs using Run 2024 Au+Au data. The prominent peak arises from $\pi^{0}\to\gamma\gamma$ decays.
An example of a reconstructed EMCal di-cluster invariant mass distribution, similar to those used for in situ EMCal tower calibrations. The distributions are made from EMCal cluster pairs using a GEANT-4 simulation of HIJING events. The prominent peak arises from $\pi^{0}\to\gamma\gamma$ decays.
An example of the measured energy distribution in a single OHCal tower, showing the MIP distribution from cosmic-ray data from the detector.
Partonic collectivity is one of the necessary signatures for the formation of quark-gluon plasma in high-energy nuclear collisions. Number of constituent quarks (NCQ) scaling has been observed for hadron elliptic flow $v_2$ in top energy nuclear collisions at the Relativistic Heavy Ion Collider and the LHC, and this has been theoretically suggested as strong evidence for partonic collectivity. In this Letter, a systematic analysis of $v_2$ of $π^{\pm}$, $K^{\pm}$, $K^{0}_{S}$, $p$, and $Λ$ in Au+Au collisions at ${\sqrt{s_{_{\rm{NN}}}}}$ = 3.2, 3.5, 3.9, and 4.5 GeV, with the STAR experiment at the Relativistic Heavy Ion Collider, is presented. NCQ scaling is markedly violated at 3.2 GeV, consistent with a hadronic-interaction dominated equation of state. However, as the collision energy increases, a gradual evolution to NCQ scaling is observed. This beam-energy dependence of $v_2$ for all hadrons studied provides evidence for the onset of dominant partonic interactions by ${\sqrt{s_{_{\rm{NN}}}}}$ = 4.5 GeV.
$p_{T}$ dependence of $v_{2}$ for $\pi^{+}$ in Au+Au collisions at 3 GeV
$p_{T}$ dependence of $v_{2}$ for $\pi^{+}$ in Au+Au collisions at 3.2 GeV
$p_{T}$ dependence of $v_{2}$ for $\pi^{+}$ in Au+Au collisions at 3.5 GeV
This paper presents a study of the inclusive forward J/$\psi$ yield as a function of forward charged-particle multiplicity in pp collisions at $\sqrt{s} = 13$ TeV using data collected by the ALICE experiment at the CERN LHC. The results are presented in terms of relative J/$\psi$ yields and relative charged-particle multiplicities with respect to these quantities obtained in inelastic collisions having at least one charged particle in the pseudorapidity range $|\eta| < 1$. The J/$\psi$ mesons are reconstructed via their decay into $\mu^+ \mu^-$ pairs in the forward rapidity region ($2.5 < y < 4$). The relative multiplicity is estimated in the forward pseudorapidity range $-3.7 < \eta < -1.7$, which overlaps with the J/$\psi$ rapidity region. The results show a steeper-than-linear increase of the J/$\psi$ yields versus the multiplicity. They are compared with previous measurements and theoretical model calculations.
Forward inclusive J/$\psi$ relative yield as a function of the relative multiplicity in −3.7 < $\eta$ < −1.7 in INEL > 0 pp collisions at $\sqrt{s}$ = 13 TeV.
We report precision measurements on cumulants ($C_{n}$) and factorial cumulants ($\kappa_{n}$) of (net-)proton number distributions up to fourth-order in Au+Au collisions from phase II of the Beam Energy Scan program at RHIC. (Anti-)protons are selected at midrapidity ($|y|<0.5$) within a transverse momentum range of $0.4 < p_T < 2.0$ GeV/$c$. The collision energy and centrality dependence of these cumulants are studied over center-of-mass energies $\sqrt{s_{NN}}$ = 7.7 -- 27 GeV. Relative to various non-critical-point model calculations and peripheral collision 70-80% data, the net-proton $C_4/C_2$ measurement in 0-5% collisions shows a minimum around 19.6 GeV for significance of deviation at $\sim2$--$5\sigma$. In addition, deviations from non-critical baselines around the same collision energy region are also seen in proton factorial cumulant ratios, especially in $\kappa_2/\kappa_1$ and $\kappa_3/\kappa_1$. Dynamical model calculations including a critical point are called for in order to understand these precision measurements.
Reference multiplicity distributions (RefMult3 and RefMult3X) for Au+Au collisions at $\sqrt{s_{NN}}$ = 19.6 GeV along with MC Glauber model fits.
Collision centrality dependence of net-proton cumulants in Au+Au collisions for $\sqrt{s_{NN}}$ = 7.7 - 27 GeV obtained with RefMult3 and RefMult3X centrality definition.
Collision energy dependence of net-proton cumulant ratios and proton factorial cumulant ratios in Au+Au collisions from $\sqrt{s_{NN}}$ = 7.7 - 200 GeV for 0-5$\%$ and 70-80$\%$ centrality. Data from $\sqrt{s_{NN}}$ = 7.7 - 27 GeV are from BES-II (obtained with RefMult3X except 27 GeV where RefMult3 is used). Data from $\sqrt{s_{NN}}$ = 39 - 200 GeV are from BES-I (RefMult3).
We measure the spin-density matrix elements (SDMEs) for the photoproduction of $ϕ(1020)$ off of the proton in its decay to $K_S^0K_L^0$, using 105 pb$^{-1}$ of data collected with a linearly polarized photon beam using the GlueX experiment. The SDMEs are measured in nine bins of the squared four-momentum transfer $t$ in the range $-t=0.15-1.0$ GeV$^2$, providing the first measurement of their $t$-dependence for photon beam energies $E_γ= 8.2-8.8$ GeV. We confirm the dominance of Pomeron exchange in this region, and put constraints on the contribution of other Regge exchanges. We also find that helicity amplitudes where the helicity of the photon and the $ϕ(1020)$ differ by two units are negligible.
Spin-density matrix elements of $\phi(1020)$ mesons produced by a linearly polarized photon beam in the helicity system. For each bin of $-t$, the limits of the bin range are given, along with the average $-\bar t$ and root-mean-square deviation $-t_\text{RMS}$ of all events that fall within the bin.
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