The first science run of the LUX-ZEPLIN (LZ) experiment, a dual-phase xenon time project chamber operating in the Sanford Underground Research Facility in South Dakota, USA, has reported leading limits on spin-independent WIMP-nucleon interactions and interactions described from a non-relativistic effective field theory (NREFT). Using the same 5.5~t fiducial mass and 60 live days of exposure we report on the results of a relativistic extension to the NREFT. We present constraints on couplings from covariant interactions arising from the coupling of vector, axial currents, and electric dipole moments of the nucleon to the magnetic and electric dipole moments of the WIMP which cannot be described by recasting previous results described by an NREFT. Using a profile-likelihood ratio analysis, in an energy region between 0~keV$_\text{nr}$ to 270~keV$_\text{nr}$, we report 90% confidence level exclusion limits on the coupling strength of five interactions in both the isoscalar and isovector bases.
Isoscalar interaction coupling limit for Lagrangian 1
Isovector interaction coupling limit for Lagrangian 19
Isoscalar interaction coupling limit for Lagrangian 19
A search for the non-resonant production of Higgs boson pairs in the $HH\rightarrow b\bar{b}\tau^+\tau^-$ channel is performed using 140 fb$^{-1}$ of proton-proton collisions at a centre-of-mass energy of $13$ TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The analysis strategy is optimised to probe anomalous values of the Higgs boson self-coupling modifier $\kappa_\lambda$ and of the quartic $HHVV$ ($V = W,Z$) coupling modifier $\kappa_{2V}$. No significant excess above the expected background from Standard Model processes is observed. An observed (expected) upper limit $\mu_{HH}<5.9$$(3.3)$ is set at 95% confidence-level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The coupling modifiers are constrained to an observed (expected) 95% confidence interval of $-3.1 < \kappa_\lambda < 9.0$ ($-2.5 < \kappa_\lambda < 9.3$) and $-0.5 < \kappa_{2V} < 2.7$ ($-0.2 < \kappa_{2V} < 2.4$), assuming all other Higgs boson couplings are fixed to the Standard Model prediction. The results are also interpreted in the context of effective field theories via constraints on anomalous Higgs boson couplings and Higgs boson pair production cross-sections assuming different kinematic benchmark scenarios.
Observed (filled circles) and expected (open circles) 95% CL upper limits on $\mu_{HH}$ from the fit of each individual channel and the combined fit in the background-only ($\mu_{HH} = 0$) hypothesis. The dashed lines indicate the expected 95% CL upper limits on $\mu_{HH}$ in the SM hypothesis ($\mu_{HH} = 1$). The inner and outer bands indicate the $\pm 1\sigma$ and $\pm 2\sigma$ variations, respectively, on the expected limit with respect to the background-only hypothesis due to statistical and systematic uncertainties.
Observed and expected 95% CL upper limits on $\mu_{HH}$, $\mu_{ggF}$ and $\mu_{VBF}$ from the individual SR likelihood fits as well as the combined results. The $\mu_{ggF}$ and $\mu_{VBF}$ limits are quoted both from the results of the simultaneous fit of both signal strengths (central column), and from independent fits for the individual production modes, assuming the other to be as predicted by the SM. The uncertainties quoted on the combined expected upper limits correspond to the 1σ uncertainty band.
Observed (solid line) value of $-2\ln\Lambda$ as a function of $\kappa_{\lambda}$ for the combined fit, when all other coupling modifiers are fixed to their SM predictions.
With the STAR experiment at the BNL Relativisic Heavy Ion Collider, we characterize $\sqrt{s_\mathrm{NN}}$ = 200 GeV p+Au collisions by event activity (EA) measured within the pseudorapidity range $eta$$in$ [-5, -3.4] in the Au-going direction and report correlations between this EA and hard- and soft- scale particle production at midrapidity ($\eta$$\in$ [-1, 1]). At the soft scale, charged particle production in low-EA p+Au collisions is comparable to that in p+p collisions and increases monotonically with increasing EA. At the hard scale, we report measurements of high transverse momentum (pT) jets in events of different EAs. In contrast with the soft particle production, high-pT particle production and EA are found to be inversely related. To investigate whether this is a signal of jet quenching in high-EA events, we also report ratios of pT imbalance and azimuthal separation of dijets in high- and low-EA events. Within our measurement precision, no significant differences are observed, disfavoring the presence of jet quenching in the highest 30% EA p+Au collisions at $\sqrt{s_\mathrm{NN}}$ = 200 GeV.
Distributions of Event Activity (as measured by the BBC) from MB and HT events with the latter satisfying an offline trigger of $E_\mathrm{T}^\mathrm{trig}>4 \mathrm{GeV}$.
Density of charged particles with $p_\mathrm{T}>0.2$ GeV/$c$ and $|\eta|\le0.9$ in ten ranges of EA for MB events and HT events selected with several offline trigger values.
Charged particle density as a function of EA, UE $\eta$, and $p_\mathrm{T,jet}^\mathrm{lead}$ for HT ($E_\mathrm{T}^\mathrm{trig}>4$ GeV) events with $p_\mathrm{T,jet}^\mathrm{raw,lead}>4~\mathrm{GeV}/c$.
Measurements of the $p_{\rm T}$-dependent flow vector fluctuations in Pb-Pb collisions at $\sqrt{s_{_{\rm NN}}} = 5.02~\mathrm{TeV}$ using azimuthal correlations with the ALICE experiment at the Large Hadron Collider are presented. A four-particle correlation approach [1] is used to quantify the effects of flow angle and magnitude fluctuations separately. This paper extends previous studies to additional centrality intervals and provides measurements of the $p_{\rm T}$-dependent flow vector fluctuations at $\sqrt{s_{_{\rm NN}}} = 5.02~\mathrm{TeV}$ with two-particle correlations. Significant $p_{\rm T}$-dependent fluctuations of the $\vec{V}_{2}$ flow vector in Pb-Pb collisions are found across different centrality ranges, with the largest fluctuations of up to $\sim$15% being present in the 5% most central collisions. In parallel, no evidence of significant $p_{\rm T}$-dependent fluctuations of $\vec{V}_{3}$ or $\vec{V}_{4}$ is found. Additionally, evidence of flow angle and magnitude fluctuations is observed with more than $5\sigma$ significance in central collisions. These observations in Pb-Pb collisions indicate where the classical picture of hydrodynamic modeling with a common symmetry plane breaks down. This has implications for hard probes at high $p_{\rm T}$, which might be biased by $p_{\rm T}$-dependent flow angle fluctuations of at least 23% in central collisions. Given the presented results, existing theoretical models should be re-examined to improve our understanding of initial conditions, quark--gluon plasma properties, and the dynamic evolution of the created system.
The ratio $v_{2}{2}/v_2[2]$ as a function of $p_{\rm T}$ in different centrality intervals
The ratio $v_{3}{2}/v_3[2]$ as a function of $p_{\rm T}$ in different centrality intervals
The ratio $v_{4}{2}/v_4[2]$ as a function of $p_{\rm T}$ in different centrality intervals
The $p_{\rm T}$-differential production cross sections of non-prompt ${\rm D^0}$, ${\rm D^+}$, and ${\rm D_s^+}$ mesons originating from beauty-hadron decays are measured in proton$-$proton collisions at a centre-of-mass energy $\sqrt{s}=13$ TeV. The measurements are performed at midrapidity, $|y| < 0.5$, with the data sample collected by ALICE from 2016 to 2018. The results are in agreement with predictions from several perturbative QCD calculations. The fragmentation fraction of beauty quarks to strange mesons divided by the one to non-strange mesons, $f_{\rm{s}}/(f_{\rm{u}} + f_{\rm{d}})$, is found to be $0.114 \pm 0.016~{\rm (stat.)} \pm 0.006~{\rm (syst.)} \pm 0.003~{\rm (BR)} \pm 0.003~{\rm (extrap.)}$. This value is compatible with previous measurements at lower centre-of-mass energies and in different collision systems in agreement with the assumption of universality of fragmentation functions. In addition, the dependence of the non-prompt D meson production on the centre-of-mass energy is investigated by comparing the results obtained at $\sqrt{s} = 5.02$ and 13 TeV, showing a hardening of the non-prompt D-meson $p_{\rm T}$-differential production cross section at higher $\sqrt{s}$. Finally, the ${\rm b\overline{b}}$ production cross section per unit of rapidity at midrapidity is calculated from the non-prompt ${\rm D^0}$, ${\rm D^+}$, ${\rm D_s^+}$, and $\Lambda_{\rm c}^+$ hadron measurements, obtaining ${\rm d}\sigma/{\rm d}y = 75.2\pm 3.2~(\mathrm{stat.}) \pm 5.2~(\mathrm{syst.})^{+12.3}_{-3.2} ~(\mathrm{extrap.})\text{ } \rm \mu b \;.$
$p_{\mathrm{T}}$-differential non-prompt $\mathrm{D}^{0}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{0}\rightarrow\mathrm{K}^-\pi^+$: $(3.95 \pm 0.03)\%$. Global relative uncertainty on BR: $0.8\%$ Global relative uncertainty on luminosity: $1.6\%$
$p_{\mathrm{T}}$-differential non-prompt $\mathrm{D}^{+}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{+}\rightarrow\mathrm{K}^-\pi^+\pi^+$: $(9.38 \pm 0.16)\%$. Global relative uncertainty on BR: $1.7\%$ Global relative uncertainty on luminosity: $1.6\%$
$p_{\mathrm{T}}$-differential $\mathrm{D}^{+}_\mathrm{s}$ production cross section at midrapidity ($|y|<0.5$) in pp collisions at $\sqrt{s}$ = 13 TeV Branching ratio of $\mathrm{D}^{+}_\mathrm{s}\rightarrow\phi\pi^+\rightarrow\mathrm{K}^+\mathrm{K}^-\pi^+$: $(2.22 \pm 0.06)\%$. Global relative uncertainty on BR: $2.7\%$ Global relative uncertainty on luminosity: $1.6\%$
A search for high-mass resonances decaying into a $\tau$-lepton and a neutrino using proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV is presented. The full Run 2 data sample corresponding to an integrated luminosity of 139 fb$^{-1}$ recorded by the ATLAS experiment in the years 2015-2018 is analyzed. The $\tau$-lepton is reconstructed in its hadronic decay modes and the total transverse momentum carried out by neutrinos is inferred from the reconstructed missing transverse momentum. The search for new physics is performed on the transverse mass between the $\tau$-lepton and the missing transverse momentum. No excess of events above the Standard Model expectation is observed and upper exclusion limits are set on the $W^\prime\to \tau \nu$ production cross-section. Heavy $W^\prime$ vector bosons with masses up to 5.0 TeV are excluded at 95% confidence level, assuming that they have the same couplings as the Standard Model $W$ boson. For non-universal couplings, $W^\prime$ bosons are excluded for masses less than 3.5-5.0 TeV, depending on the model parameters. In addition, model-independent limits on the visible cross-section times branching ratio are determined as a function of the lower threshold on the transverse mass of the $\tau$-lepton and missing transverse momentum.
Observed and predicted $m_{\rm T}$ distributions including SSM and NU (cot$\theta$ = 5.5) $W^{\prime}$ signals with masses of 4 TeV. Please note that in the paper figure the bin content is divided by the bin width, but this is not done in the HepData table.
Observed and expected 95% CL upper limits on cross section times $\tau\nu$ branching fraction for $W^{\prime}_{\rm SSM}$.
Regions of the non-universal parameter space excluded at 95% CL.
Searches for dark matter with liquid xenon time projection chamber experiments have traditionally focused on the region of the parameter space that is characteristic of weakly interacting massive particles, ranging from a few GeV/$c^2$ to a few TeV/$c^2$. Models of dark matter with a mass much heavier than this are well motivated by early production mechanisms different from the standard thermal freeze-out, but they have generally been less explored experimentally. In this work, we present a re-analysis of the first science run (SR1) of the LZ experiment, with an exposure of $0.9$ tonne$\times$year, to search for ultraheavy particle dark matter. The signal topology consists of multiple energy deposits in the active region of the detector forming a straight line, from which the velocity of the incoming particle can be reconstructed on an event-by-event basis. Zero events with this topology were observed after applying the data selection calibrated on a simulated sample of signal-like events. New experimental constraints are derived, which rule out previously unexplored regions of the dark matter parameter space of spin-independent interactions beyond a mass of 10$^{17}$ GeV/$c^2$.
Upper limit on the WIMP-nucleon scattering cross section from the multiple-scatter analysis.
Upper limit on the WIMP-nucleus scattering cross section from the multiple-scatter analysis.
Upper limit on the WIMP-nucleon scattering cross section from the single-scatter analysis.
A combination of fifteen top quark mass measurements performed by the ATLAS and CMS experiments at the LHC is presented. The data sets used correspond to an integrated luminosity of up to 5 and 20$^{-1}$ of proton-proton collisions at center-of-mass energies of 7 and 8 TeV, respectively. The combination includes measurements in top quark pair events that exploit both the semileptonic and hadronic decays of the top quark, and a measurement using events enriched in single top quark production via the electroweak $t$-channel. The combination accounts for the correlations between measurements and achieves an improvement in the total uncertainty of 31% relative to the most precise input measurement. The result is $m_\mathrm{t}$ = 172.52 $\pm$ 0.14 (stat) $\pm$ 0.30 (syst) GeV, with a total uncertainty of 0.33 GeV.
Uncertainties on the $m_{t}$ values extracted in the LHC, ATLAS, and CMS combinations arising from the categories described in the text, sorted in order of decreasing value of the combined LHC uncertainty.
Atomic nuclei are self-organized, many-body quantum systems bound by strong nuclear forces within femtometer-scale space. These complex systems manifest a variety of shapes, traditionally explored using non-invasive spectroscopic techniques at low energies. However, at these energies, their instantaneous shapes are obscured by long-timescale quantum fluctuations, making direct observation challenging. Here we introduce the ``collective flow assisted nuclear shape imaging'' method, which images the nuclear global shape by colliding them at ultrarelativistic speeds and analyzing the collective response of outgoing debris. This technique captures a collision-specific snapshot of the spatial matter distribution within the nuclei, which, through the hydrodynamic expansion, imprints patterns on the particle momentum distribution observed in detectors. We benchmark this method in collisions of ground state Uranium-238 nuclei, known for their elongated, axial-symmetric shape. Our findings show a large deformation with a slight deviation from axial symmetry in the nuclear ground state, aligning broadly with previous low-energy experiments. This approach offers a new method for imaging nuclear shapes, enhances our understanding of the initial conditions in high-energy collisions and addresses the important issue of nuclear structure evolution across energy scales.
Data from Figure 2, panel a, Au+Au, 0-0.5% Centrality, 0.2<p_{T}<3 GeV/c, systematics include non-flow difference in the two systems, but correlated non-flow systematics with the value of $\delta \left\langle v_{2}^{2}\right\rangle$ =+-3.2e-5 included
Data from Figure 2, panel a, U+U, 0-0.5% Centrality, 0.2<p_{T}<3 GeV/c, systematics include non-flow difference in the two systems, but correlated non-flow systematics with the value of $\delta \left\langle v_{2}^{2}\right\rangle$ =+-3.2e-5 included
Data from Figure 2, panel b, Au+Au, 0-0.5% Centrality, 0.2<p_{T}<3 GeV/c
The first measurements of femtoscopic correlations with the particle pair combinations $\pi^\pm$K$^0_{\rm S}$ in pp collisions at $\sqrt{s}=13$ TeV at the Large Hadron Collider (LHC) are reported by the ALICE experiment. Using the femtoscopic approach, it is shown that it is possible to study the elusive K$^*_0(700)$ particle that has been considered a tetraquark candidate for over forty years. Source and final-state interaction parameters are extracted by fitting a model assuming a Gaussian source to the experimentally measured two-particle correlation functions. The final-state interaction in the $\pi^\pm$K$^0_{\rm S}$ system is modeled through a resonant scattering amplitude, defined in terms of a mass and a coupling parameter. The extracted mass and Breit-Wigner width, derived from the coupling parameter, of the final-state interaction are found to be consistent with previous measurements of the K$^*_0(700)$. The small value and increase of the correlation strength with increasing source size support the hypothesis that the K$^*_0(700)$ is a four-quark state, i.e. a tetraquark state of the form $({\rm q_1},\overline{\rm q_2}, {\rm q_3}, \overline{\rm q_3})$ in which ${\rm q_1}$, ${\rm q_2}$, and ${\rm q_3}$ indicate the flavor of the valence quarks of the $\pi$ and K$^0_{\rm S}$. This latter trend is also confirmed via a simple geometric model that assumes a tetraquark structure of the K$^*_0(700)$ resonance.
Experimental $C(k^*)$, 0-100% mult. class, $k_{\rm T}>0$.
PYTHIA $C(k^*)$, 0-100% mult. class, $k_{\rm T}>0$.
Experimental $C(k^*)$, 0-100% mult. class, $k_{\rm T}<0.5$ GeV/$c$.
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