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Searches for hidden sectors using $K^+\toπ^+X$ decays

The NA62 collaboration Cortina Gil, Eduardo ; Jerhot, Jan ; Minucci, Elisa ; et al.
CERN-EP-2025-167, 2025.
Inspire Record 2953428 DOI 10.17182/hepdata.160245

Results from the study of the rare decays $K^+\toπ^+ν\barν$, $K^{+}\rightarrowπ^{+}μ^{+}μ^{-}$ and $K^{+}\rightarrowπ^{+}γγ$ at the NA62 experiment at CERN are interpreted in terms of improved limits for $\rm{B}(K^+\toπ^+X)$ and coupling parameters of hidden-sector models, where $X$ is a mediator. World-leading limits are achieved for dark photon, dark scalar and axion-like particle models.

50 data tables

Number of expected and observed events as a function of squared missing mass.

Number of expected and observed events as a function of squared missing mass.

Single Event Sensitivity (SES) for the $K^{+}\rightarrow\pi^{+}X$ search as a function of X mass.

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Imaging nuclear shape through anisotropic and radial flow in high-energy heavy-ion collisions

The EMAIL:star-publication@bnl.gov & STAR collaborations
Rept.Prog.Phys. 88 (2025) 108601, 2025.
Inspire Record 2937844 DOI 10.17182/hepdata.159930

Most atomic nuclei exhibit ellipsoidal shapes characterized by quadrupole deformation $β_2$ and triaxiality $γ$, and sometimes even a pear-like octupole deformation $β_3$. The STAR experiment introduced a new "imaging-by-smashing" technique [arXiv:2401.06625, arXiv:2501.16071] to image the nuclear global shape by colliding nuclei at ultra-relativistic speeds and analyzing outgoing debris. Features of nuclear shape manifest in collective observables like anisotropic flow $v_n$ and radial flow via mean transverse momentum $[p_{\mathrm{T}}]$. We present new measurements of the variances of $v_n$ ($n=2$, 3, and 4) and $[p_{\mathrm{T}}]$, and the covariance of $v_n^2$ with $[p_{\mathrm{T}}]$, in collisions of highly deformed $^{238}$U and nearly spherical $^{197}$Au. Ratios of these observables between the two systems effectively suppress common final-state effects, isolating the strong impact of uranium's deformation. By comparing results with state-of-the-art hydrodynamic model calculations, we extract $β_{2\mathrm{U}}$ and $γ_{\mathrm{U}}$ values consistent with those deduced from low-energy nuclear structure measurements. Measurements of $v_3$ and its correlation with $[p_{\mathrm{T}}]$ also provide the first experimental suggestion of a possible octupole deformation for $^{238}$U. These findings provide significant support for using high-energy collisions to explore nuclear shapes on femtosecond timescales, with implications for both nuclear structure and quark-gluon plasma studies.

169 data tables

Data from Figure 2, panel a, $p(N_{ch}^{rec})$

Data from Figure 2, panel b, $p(N_{ch}^{rec})$

Data from Figure 3, panel a, Au+Au

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Measurement of medium-induced acoplanarity in central Au-Au and pp collisions at $\sqrt{s_{\rm NN}}=200$ GeV using direct-photon+jet and $\pi^{0}$+jet correlations

The STAR collaboration
PRL; 3 figures+1 figure in End Matter, 2025.
Inspire Record 2919952 DOI 10.17182/hepdata.159953

The STAR Collaboration reports measurements of acoplanarity using semi-inclusive distributions of charged-particle jets recoiling from direct photon and $\pi^{0}$ triggers, in central Au-Au and pp collisions at $\sqrt{s_{\rm NN}}=200$ GeV. Significant medium-induced acoplanarity broadening is observed for large but not small recoil jet resolution parameter, corresponding to recoil jet yield enhancement up to a factor of $\approx20$ for trigger-recoil azimuthal separation far from $\pi$. This phenomenology is indicative of the response of the Quark-Gluon Plasma to excitation, but not the scattering of jets off of its quasiparticles. The measurements are not well-described by current theoretical models which incorporate jet quenching.

18 data tables

Corrected Yield R=0.2 pi0+jet 10-15 pp at sqrt{s_{NN}}=200 GeV

Corrected Yield R=0.2 pi0+jet 15-20 pp at sqrt{s_{NN}}=200 GeV

Corrected Yield R=0.5 pi0+jet 10-15 pp at sqrt{s_{NN}}=200 GeV

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Combination and interpretation of differential Higgs boson production cross sections in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Chekhovsky, Vladimir ; Hayrapetyan, Aram ; Makarenko, Vladimir ; et al.
CMS-HIG-23-013, 2025.
Inspire Record 2913615 DOI 10.17182/hepdata.156816

Precision measurements of Higgs boson differential production cross sections are a key tool to probe the properties of the Higgs boson and test the standard model. New physics can affect both Higgs boson production and decay, leading to deviations from the distributions that are expected in the standard model. In this paper, combined measurements of differential spectra in a fiducial region matching the experimental selections are performed, based on analyses of four Higgs boson decay channels ($\gamma\gamma$, ZZ$^{(*)}$, WW$^{(*)}$, and $\tau\tau$) using proton-proton collision data recorded with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The differential measurements are extrapolated to the full phase space and combined to provide the differential spectra. A measurement of the total Higgs boson production cross section is also performed using the $\gamma\gamma$ and ZZ decay channels, with a result of 53.4$^{+2.9}_{-2.9}$ (stat)$^{+1.9}_{-1.8}$ (syst) pb, consistent with the standard model prediction of 55.6 $\pm$ 2.5 pb. The fiducial measurements are used to compute limits on Higgs boson couplings using the $\kappa$-framework and the SM effective field theory.

17 data tables

Observed best fit differential cross section for the $p_{T}^{H}$ observable

Observed best fit differential cross section for the $N_{jets}$ observable

Observed best fit differential cross section for the $p_{T}^{j1}$ (GeV) observable

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Search for hadronic decays of feebly-interacting particles at NA62

The NA62 collaboration Cortina Gil, Eduardo ; Jerhot, Jan ; Lurkin, Nicolas ; et al.
Eur.Phys.J.C 85 (2025) 571, 2025.
Inspire Record 2877075 DOI 10.17182/hepdata.156981

The NA62 experiment at CERN has the capability to collect data in a beam-dump mode, where 400 GeV protons are dumped on an absorber. In this configuration, New Physics particles, including dark photons, dark scalars, and axion-like particles, may be produced in the absorber and decay in the instrumented volume beginning approximately 80 m downstream of the dump. A search for these particles decaying in flight to hadronic final states is reported, based on an analysis of a sample of $1.4 \times 10^{17}$ protons on dump collected in 2021. No evidence of a New Physics signal is observed, excluding new regions of parameter spaces of multiple models.

66 data tables

90% CL upper limit in dark photon coupling vs mass parameter space for combined di-lepton and hadronic final states, using bremsstrahlung production without the time-like form factor.

90% CL upper limit in dark photon coupling vs mass parameter space for combined di-lepton and hadronic final states, including mixing and bremsstrahlung production with a time-like form factor.

90% CL upper limit in dark scalar coupling vs mass parameter space for combined di-lepton and hadronic final states.

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First Measurement of the Muon Neutrino Interaction Cross Section and Flux as a Function of Energy at the LHC with FASER

The FASER collaboration Mammen Abraham, Roshan ; Ai, Xiaocong ; Anders, John ; et al.
Phys.Rev.Lett. 134 (2025) 211801, 2025.
Inspire Record 2855783 DOI 10.17182/hepdata.156838

This letter presents the measurement of the energy-dependent neutrino-nucleon cross section in tungsten and the differential flux of muon neutrinos and anti-neutrinos. The analysis is performed using proton-proton collision data at a center-of-mass energy of $13.6 \, {\rm TeV}$ and corresponding to an integrated luminosity of $(65.6 \pm 1.4) \, \mathrm{fb^{-1}}$. Using the active electronic components of the FASER detector, $338.1 \pm 21.0$ charged current muon neutrino interaction events are identified, with backgrounds from other processes subtracted. We unfold the neutrino events into a fiducial volume corresponding to the sensitive regions of the FASER detector and interpret the results in two ways: We use the expected neutrino flux to measure the cross section, and we use the predicted cross section to measure the neutrino flux. Both results are presented in six bins of neutrino energy, achieving the first differential measurement in the TeV range. The observed distributions align with Standard Model predictions. Using this differential data, we extract the contributions of neutrinos from pion and kaon decays.

32 data tables

The systematic uncertainties of the fitted number of neutrino interactions.

The systematic uncertainties of the fitted number of anti-neutrino interactions.

The systematic uncertainties of the fitted number of neutrino and anti-neutrino interactions.

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Multiplicities of positive and negative pions, kaons and unidentified hadrons from deep-inelastic scattering of muons off a liquid hydrogen target

The COMPASS collaboration Alexeev, G.D. ; Alexeev, M.G. ; Alice, C. ; et al.
Phys.Rev.D 112 (2025) 012002, 2025.
Inspire Record 2840545 DOI 10.17182/hepdata.159544

The multiplicities of positive and negative pions, kaons and unidentified hadrons produced in deep-inelastic scattering are measured in bins of the Bjorken scaling variable $x$, the relative virtual-photon energy $y$ and the fraction of the virtual-photon energy transferred to the final-state hadron $z$. Data were obtained by the COMPASS Collaboration using a 160 GeV muon beam of both electric charges and a liquid hydrogen target. These measurements cover the kinematic domain with photon virtuality $Q^2 > 1$ (GeV/$c)^2$, $0.004 < x < 0.4$, $0.1 < y < 0.7$ and $0.2 < z < 0.85$, in accordance with the kinematic domain used in earlier published COMPASS multiplicity measurements with an isoscalar target. The calculation of radiative corrections was improved by using the Monte Carlo generator DJANGOH, which results in up to 12% larger corrections in the low-$x$ region.

3 data tables

h+/h- multiplicities in (x, y, z) bins with corrections, applied corrections for VM and RC are provided in the table

pi+/pi- multiplicities in (x, y, z) bins with corrections, applied corrections for VM and RC are provided in the table

K+/K- multiplicities in (x, y, z) bins with corrections, applied corrections for VM and RC are provided in the table


Light Nuclei Femtoscopy and Baryon Interactions in 3 GeV Au+Au Collisions at RHIC

The STAR collaboration Aboona, B.E. ; Adam, J. ; Adamczyk, L. ; et al.
Phys.Lett.B 864 (2025) 139412, 2025.
Inspire Record 2837311 DOI 10.17182/hepdata.156057

We report the measurements of proton-deuteron ($p$-$d$) and deuteron-deuteron ($d$-$d$) correlation functions in Au+Au collisions at $\sqrt{s_\mathrm{NN}}$ = 3 GeV using fixed-target mode with the STAR experiment at the Relativistic Heavy-Ion Collider (RHIC). For the first time, the source size ($R_{G}$), scattering length ($f_{0}$), and effective range ($d_{0}$) are extracted from the measured correlation functions with a simultaneous fit. The spin-averaged $f_0$ for $p$-$d$ and $d$-$d$ interactions are determined to be -5.28 $\pm$ 0.11(stat.) $\pm$ 0.82(syst.) fm and -2.62 $\pm$ 0.02(stat.) $\pm$ 0.24(syst.) fm, respectively. The measured $p$-$d$ interaction is consistent with theoretical calculations and low-energy scattering experiment results, demonstrating the feasibility of extracting interaction parameters using the femtoscopy technique. The reasonable agreement between the experimental data and the calculations from the transport model indicates that deuteron production in these collisions is primarily governed by nucleon coalescence.

3 data tables

Proton-Deuteron correlation function in 3 GeV Au+Au collisions.

Deuteron-Deuteron correlation function in 3 GeV Au+Au collisions.

Source size of p-d and d-d correlation function


Energy-scaling behavior of intrinsic transverse momentum parameters in Drell-Yan simulation

The CMS collaboration Hayrapetyan, Aram ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.D 111 (2025) 072003, 2025.
Inspire Record 2839223 DOI 10.17182/hepdata.154142

An analysis is presented based on models of the intrinsic transverse momentum (intrinsic $k_\mathrm{T}$) of partons in nucleons by studying the dilepton transverse momentum in Drell-Yan events. Using parameter tuning in event generators and existing data from fixed-target experiments and from hadron colliders, our investigation spans three orders of magnitude in center-of-mass energy and two orders of magnitude in dilepton invariant mass. The results show an energy-scaling behavior of the intrinsic $k_\mathrm{T}$ parameters, independent of the dilepton invariant mass at a given center-of-mass energy.

45 data tables

Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP5 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.

Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP4 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.

Tuned intrinsic kT parameters BeamRemnants:PrimordialkThard in Pythia with the underlying-event tune CP3 at nucleon-nucleon center-of-mass energy from 38.8 GeV to 13 TeV.

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Temperature Measurement of Quark-Gluon Plasma at Different Stages

The STAR collaboration Aboona, B.E. ; Adam, J. ; Adamczyk, L. ; et al.
Nature Commun. 16 (2025) 9098, 2025.
Inspire Record 2755369 DOI 10.17182/hepdata.147195

In a Quark-Gluon Plasma (QGP), the fundamental building blocks of matter, quarks and gluons, are under extreme conditions of temperature and density. A QGP could exist in the early stages of the Universe, and in various objects and events in the cosmos. The thermodynamic and hydrodynamic properties of the QGP are described by Quantum Chromodynamics (QCD) and can be studied in heavy-ion collisions. Despite being a key thermodynamic parameter, the QGP temperature is still poorly known. Thermal lepton pairs ($e^+e^-$ and $\mu^+\mu^-$) are ideal penetrating probes of the true temperature of the emitting source, since their invariant-mass spectra suffer neither from strong final-state interactions nor from blue-shift effects due to rapid expansion. Here we measure the QGP temperature using thermal $e^+e^-$ production at the Relativistic Heavy Ion Collider (RHIC). The average temperature from the low-mass region (in-medium $\rho^0$ vector-meson dominant) is $(1.99 \pm 0.24) \times 10^{12}$ K, consistent with the chemical freeze-out temperature from statistical models and the phase transition temperature from LQCD. The average temperature from the intermediate mass region (above the $\rho^0$ mass, QGP dominant) is significantly higher at $(3.40 \pm 0.55)\times 10^{12}$ K. This work provides essential experimental thermodynamic measurements to map out the QCD phase diagram and understand the properties of matter under extreme conditions.

5 data tables

The inclusive dielectron invariant mass spectra of 27 GeV in 0-80% centrality.

The inclusive dielectron invariant mass spectra of 54.4 GeV in 0-80% centrality.

The charged multiplicity normalzied excess yield of 27 GeV in 0-80% centrality.

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