Date

Study of excited $\Lambda_\mathrm{b}^0$ states decaying to $\Lambda_\mathrm{b}^0\pi^+\pi^-$ in proton-proton collisions at $\sqrt{s} =$ 13 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Lett.B 803 (2020) 135345, 2020.
Inspire Record 1776599 DOI 10.17182/hepdata.93064

A study of excited $\Lambda_\mathrm{b}^0$ baryons is reported, based on a data sample collected in 2016-2018 with the CMS detector at the LHC in proton-proton collisions at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of up to 140 fb$^{-1}$. The existence of four excited $\Lambda_\mathrm{b}^0$ states: $\Lambda_\mathrm{b}$(5912)$^0$, $\Lambda_\mathrm{b}$(5920)$^0$, $\Lambda_\mathrm{b}$(6146)$^0$, and $\Lambda_\mathrm{b}$(6152)$^0$ in the $\Lambda_\mathrm{b}^0\pi^+\pi^-$ mass spectrum is confirmed, and their masses are measured. The $\Lambda_\mathrm{b}^0\pi^+\pi^-$ mass distribution exhibits a broad excess of events in the region of 6040-6100 MeV, whose origin cannot be discerned with the present data.

2 data tables

Measured mass differences


$K^{*}(892)^0$ meson production in inelastic p+p interactions at 158 GeV/$c$ beam momentum measured by NA61/SHINE at the CERN SPS

The NA61/SHINE collaboration Aduszkiewicz, A. ; Andronov, E.V. ; Antićić, T. ; et al.
Eur.Phys.J.C 80 (2020) 460, 2020.
Inspire Record 1775731 DOI 10.17182/hepdata.94255

The measurement of $K^{*}(892)^0$ resonance production via its $K^{+}\pi^{-}$ decay mode in inelastic p+p collisions at beam momentum 158 GeV/$c$ ($\sqrt{s_{NN}}=17.3$ GeV) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The $\textit{template}$ method was used to extract the $K^{*}(892)^0$ signal and double differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of $K^{*}(892)^0$ mesons was found to be $(78.44 \pm 0.38 \mathrm{(stat)} \pm 6.0 \mathrm{(sys)) \cdot 10^{-3}}$. The NA61/SHINE results are compared with the E$_{POS}$1.99 and Hadron Resonance Gas models as well as with world data from p+p and nucleus-nucleus collisions.

11 data tables

Numerical values of mass and width of $K^{∗}(892)^0$ mesons fitted in 0<y<0.5 and presented in Fig.8. The first uncertainty is statistical, while the second one is systematic.

Numerical values of double-differential yields $d^{2}n/dydp_{T}$ presented in Fig. 10, given in units of $10^{−3} (GeV/c)^{−1}$. The first uncertainty is statistical, while the second one is systematic

Numerical values of double-differential yields $d^{2}n/dydp_{T}$ presented in Fig. 10, given in units of $10^{−3} (GeV/c)^{−1}$. The first uncertainty is statistical, while the second one is systematic

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Net-proton number fluctuations and the Quantum Chromodynamics critical point

The STAR collaboration Adam, J. ; Adam, J. ; Adamczyk, L. ; et al.
Phys.Rev.Lett. 126 (2021) 092301, 2021.
Inspire Record 1850675 DOI 10.17182/hepdata.101068

Non-monotonic variation with collision energy ($\sqrt{s_{\rm NN}}$) of the moments of the net-baryon number distribution in heavy-ion collisions, related to the correlation length and the susceptibilities of the system, is suggested as a signature for the Quantum Chromodynamics (QCD) critical point. We report the first evidence of a non-monotonic variation in kurtosis times variance of the net-proton number (proxy for net-baryon number) distribution as a function of \rootsnn with 3.1$\sigma$ significance, for head-on (central) gold-on-gold (Au+Au) collisions measured using the STAR detector at RHIC. Data in non-central Au+Au collisions and models of heavy-ion collisions without a critical point show a monotonic variation as a function of $\sqrt{s_{\rm NN}}$.

10 data tables

Event-by-event net-proton multiplicity distributions for central (0-5$\%$) Au+Au collisions from $\sqrt{s_{NN}} = 7.7 - 200 GeV. The distributions are normalised to total number of events. The distributions are not corrected for proton and antiproton detection efficiency.

Cumulants of net-proton distributions in Au+Au collisions for nine energies from $\sqrt{s_{NN}} = 7.7 - 200 GeV for 0-5$\%$ and 70-80$\%$ centrality.

Cumulant ratios C3/C2 and C4/C2 of net-proton distributions in Au+Au collisions for eight energies from $\sqrt{s_{NN}} = 7.7 - 62.4 GeV for 0-5$\%$ centrality. Also given are the derivative of the polynomial fits to the C3/C2 and C4/C2 vs energy at each energy and the Skellam baselines for the ratios.

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Search for an exotic S=-2, Q=-2 baryon resonance in proton-proton interactions at $\sqrt{s_{NN}}$ = 17.3~GeV

The NA61/SHINE collaboration Aduszkiewicz, A. ; Andronov, E.V. ; Antićić, T. ; et al.
Phys.Rev.D 101 (2020) 051101, 2020.
Inspire Record 1773266 DOI 10.17182/hepdata.94256

Pentaquark states have been extensively investigated theoretically in the context of the constituent quark model. In this paper experimental searches in the $Xi^{-}\pi^{-}$, $Xi^{-}\pi^{+}$, $Xi^{+}\pi^{-}$ and $Xi^{+}\pi^{+}$ invariant mass spectra in proton-proton interactions at $\sqrt{s}$=17.3 GeV are presented. Previous possible evidence from the NA49 collaboration of the existence of a narrow $Xi^{-}\pi^{-}$ baryon resonance in p+p interactions is not confirmed with almost 10 times greater event statistics. The search was performed using the NA61/SHINE detector which reuses the main components of the NA49 apparatus. No signal was observed with either the selection cuts of NA49 or a newly optimised set.

5 data tables

Invariant mass spectra of XI-PI-, XI-PI+, XI+PI-, XI+PI+.

Sum of invariant mass spectra of XI-PI-, XI-PI+, XI+PI-, XI+PI+.

Invariant mass spectra of XI-PI-, XI-PI+, XI+PI-, XI+PI+.

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$J/\psi$ and $\psi(2S)$ production at forward rapidity in $p$+$p$ collisions at $\sqrt{s}=510$ GeV

The PHENIX collaboration Acharya, U.A. ; Adare, A. ; Aidala, C. ; et al.
Phys.Rev.D 101 (2020) 052006, 2020.
Inspire Record 1773662 DOI 10.17182/hepdata.140524

The PHENIX experiment at the Relativistic Heavy Ion Collider has measured the differential cross section, mean transverse momentum, mean transverse momentum squared of inclusive $J/\psi$ and cross-section ratio of $\psi(2S)$ to $J/\psi$ at forward rapidity in \pp collisions at \sqrts = 510 GeV via the dimuon decay channel. Comparison is made to inclusive $J/\psi$ cross sections measured at \sqrts = 200 GeV and 2.76--13 TeV. The result is also compared to leading-order nonrelativistic QCD calculations coupled to a color-glass-condensate description of the low-$x$ gluons in the proton at low transverse momentum ($p_T$) and to next-to-leading order nonrelativistic QCD calculations for the rest of the $p_T$ range. These calculations overestimate the data at low $p_T$. While consistent with the data within uncertainties above $\approx3$ GeV/$c$, the calculations are systematically below the data. The total cross section times the branching ratio is BR $d\sigma^{J/\psi}_{pp}/dy (1.2<|y|<2.2, 0

3 data tables

The total cross section times the branching ratio.

The inclusive $J/\psi$ differential cross section as a function of $p_T$ at 1.2 < $|y|$ < 2.2 at 510 GeV.

The inclusive $J/\psi$ differential cross section integrated over 0 < $p_T$ < 10 GeV/$c$ as a function of rapidity at 510 GeV.


Proton-Proton Interactions and Onset of Deconfinement

The NA61/SHINE collaboration Aduszkiewicz, A. ; Andronov, E.V. ; Anticic, T. ; et al.
Phys.Rev.C 102 (2020) 011901, 2020.
Inspire Record 1772241 DOI 10.17182/hepdata.95182

The NA61/SHINE experiment at the CERN SPS is performing a uniqe study of the phase diagram of strongly interacting matter by varying collision energy and nuclear mass number of colliding nuclei. In central Pb+Pb collisions the NA49 experiment found structures in the energy dependence of several observables in the CERN SPS energy range that had been predicted for the transition to a deconfined phase. New measurements of NA61/SHINE find intriguing similarities in p+p interactions for which no deconfinement transition is expected at SPS energies. Possible implications will be discussed.

12 data tables

K+/PI+ at y=0.

K+/PI+ at y=0.

<K+>/<PI+>.

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Measurement of the top quark forward-backward production asymmetry and the anomalous chromoelectric and chromomagnetic moments in pp collisions at $\sqrt{s} =$ 13 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
JHEP 06 (2020) 146, 2020.
Inspire Record 1772050 DOI 10.17182/hepdata.95469

The parton-level top quark (t) forward-backward asymmetry and the anomalous chromoelectric ($\hat{d}_\mathrm{t}$) and chromomagnetic ($\hat{\mu}_\mathrm{t}$) moments have been measured using LHC pp collisions at a center-of-mass energy of 13 TeV, collected in the CMS detector in a data sample corresponding to an integrated luminosity of 35.9 fb$^{-1}$. The linearized variable $A_\mathrm{FB}^{(1)}$ is used to approximate the asymmetry. Candidate $\mathrm{t\bar{t}}$ events decaying to a muon or electron and jets in final states with low and high Lorentz boosts are selected and reconstructed using a fit of the kinematic distributions of the decay products to those expected for $\mathrm{t\bar{t}}$ final states. The values found for the parameters are $A_\mathrm{FB}^{(1)} =$ 0.048 $^{+0.095}_{-0.087}$ (stat) $^{+0.020}_{-0.029}$ (syst), $\hat{\mu}_\mathrm{t} =-$ 0.024 $^{+0.013}_{-0.009}$ (stat) $^{+0.016}_{-0.011}$ (syst), and a limit is placed on the magnitude of $|\hat{d}_\mathrm{t}|$ $<$ 0.03 at 95% confidence level.

3 data tables

Linearized top quark forward-backward production asymmetry $A_{FB}^{(1)}$

Top quark anomalous chromomagnetic dipole moment $\hat{\mu}_{t}$

Top quark anomalous chromoelectric dipole moment $\hat{d}_{t}$


Measurement of the $\chi_\mathrm{c1}$ and $\chi_\mathrm{c2}$ polarizations in proton-proton collisions at $\sqrt{s} =$ 8 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.Lett. 124 (2020) 162002, 2020.
Inspire Record 1771351 DOI 10.17182/hepdata.92245

The polarizations of promptly produced $\chi_\mathrm{c1}$ and $\chi_\mathrm{c2}$ mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at $\sqrt{s} = $ 8 TeV. The $\chi_\mathrm{c}$ states are reconstructed via their radiative decays $\chi_\mathrm{c}$ $\to$ $\mathrm{J}/\psi\, \gamma$, with the photons being measured through conversions to e$^+$e$^-$, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the $\chi_\mathrm{c2}$ to $\chi_\mathrm{c1}$ yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the $\mathrm{J}/\psi$ $\to$ $\mu^+\mu^-$ decay, in three ranges of $\mathrm{J}/\psi$ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum.

6 data tables

Yield ratios of chi_c2 over chi_c1 mesons as a function of phi (HX) in the J/psi pT range 8-12 GeV

Yield ratios of chi_c2 over chi_c1 mesons as a function of phi (HX) in the J/psi pT range 12-18 GeV

Yield ratios of chi_c2 over chi_c1 mesons as a function of phi (HX) in the J/psi pT range 18-30 GeV

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Version 3
Improved Sterile Neutrino Constraints from the STEREO Experiment with 179 Days of Reactor-On Data

The STEREO collaboration Almazán, H. ; Bernard, L. ; Blanchet, A. ; et al.
Phys.Rev.D 102 (2020) 052002, 2020.
Inspire Record 1770821 DOI 10.17182/hepdata.92323

The STEREO experiment is a very short baseline reactor antineutrino experiment. It is designed to test the hypothesis of light sterile neutrinos being the cause of a deficit of the observed antineutrino interaction rate at short baselines with respect to the predicted rate, known as the reactor antineutrino anomaly. The STEREO experiment measures the antineutrino energy spectrum in six identical detector cells covering baselines between 9 and 11 m from the compact core of the ILL research reactor. In this article, results from 179 days of reactor turned on and 235 days of reactor turned off are reported at a high degree of detail. The current results include improvements in the modelling of detector optical properties and the gamma-cascade after neutron captures by gadolinium, the treatment of backgrounds, and the statistical method of the oscillation analysis. Using a direct comparison between antineutrino spectra of all cells, largely independent of any flux prediction, we find the data compatible with the null oscillation hypothesis. The best-fit point of the reactor antineutrino anomaly is rejected at more than 99.9% C.L.

25 data tables

Data from Figure 30 – Relative comparison between the estimated rates of IBD events $A_{l,i}$ (for cell $l$ and energy bin $i$) and the re-normalised no-oscillation model $\phi_i M_{l,i}(\sin^2(2\theta_{ee}) = 0)$ as a function of reconstructed energy $E_\text{rec}$ after a fit to phase-I+II data. Due to less statistics, the highest energy bin is excluded from the oscillation analysis in phase-I. For technical reasons, its value is set equal to zero in this dataset. A full graphical presentation can be downloaded at "Resources" for reference.

Data from Figure 30 – Relative comparison between the estimated rates of IBD events $A_{l,i}$ (for cell $l$ and energy bin $i$) and the fitted no-oscillation model $M_{l,i}(0, 0, \vec{\alpha})~\phi_i$ as a function of reconstructed energy $E_\text{rec}$ after a fit to phase-I+II data. Due to less statistics, the highest energy bin is excluded from the oscillation analysis in phase-I. For technical reasons, its value is set equal to zero in this dataset. A graphical presentation can be downloaded at "Resources" for reference.

Data from Figure 30 – Relative comparison between the estimated rates of IBD events $A_{l,i}$ (for cell $l$ and energy bin $i$) and the fitted no-oscillation model $M_{l,i}(0, 0, \vec{\alpha})~\phi_i$ as a function of reconstructed energy $E_\text{rec}$ after a fit to phase-I+II data. Due to less statistics, the highest energy bin is excluded from the oscillation analysis in phase-I. For technical reasons, its value is set equal to zero in this dataset. A graphical presentation can be downloaded at "Resources" for reference.

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Search for a narrow resonance lighter than 200 GeV decaying to a pair of muons in proton-proton collisions at $\sqrt{s} =$ 13 TeV

The CMS collaboration Sirunyan, Albert M ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.Lett. 124 (2020) 131802, 2020.
Inspire Record 1769657 DOI 10.17182/hepdata.99929

A search is presented for a narrow resonance decaying to a pair of oppositely charged muons using $\sqrt{s} =$ 13 TeV proton-proton collision data recorded at the LHC. In the 45-75 and 110-200 GeV resonance mass ranges, the search is based on conventional triggering and event reconstruction techniques. In the 11.5-45 GeV mass range, the search uses data collected with dimuon triggers with low transverse momentum thresholds, recorded at high rate by storing a reduced amount of trigger-level information. The data correspond to integrated luminosities of 137 fb$^{-1}$ and 96.6 fb$^{-1}$ for conventional and high-rate triggering, respectively. No significant resonant peaks are observed in the probed mass ranges. The search sets the most stringent constraints to date on a dark photon in the $\sim$30-75 and 110-200 GeV mass ranges.

3 data tables

The dimuon mass distributions of events selected with the standard muon triggers (maroon, darker), and the scouting dimuon triggers (green, lighter). Events are required to pass all the selection requirements.

Expected and observed upper limits at 95% CL on the product of the signal cross section ($\sigma$) for a narrow resonance, branching fraction to a pair of muons ($\mathcal{B}$), and acceptance ($A$) as a function of the mass of a narrow resonance. Results obtained using the scouting (standard) triggers are to the left (right) of the vertical purple line.

Expected and observed upper limits at 90% CL on $\epsilon^{2}$, the square of the kinetic mixing coefficient, as a function of the dark photon mass. Results obtained using the scouting (standard) triggers are to the left (right) of the vertical purple line.