Date

First measurement of the absorption of $^{3}\overline{\rm He}$ nuclei in matter and impact on their propagation in the galaxy

The ALICE collaboration Acharya, Shreyasi ; Adamova, Dagmar ; Adler, Alexander ; et al.
Nature Phys. 19 (2023) 61-71, 2023.
Inspire Record 2026264 DOI 10.17182/hepdata.133480

In our Galaxy, light antinuclei composed of antiprotons and antineutrons can be produced through high-energy cosmic-ray collisions with the interstellar medium or could also originate from the annihilation of dark-matter particles that have not yet been discovered. On Earth, the only way to produce and study antinuclei with high precision is to create them at high-energy particle accelerators. Although the properties of elementary antiparticles have been studied in detail, the knowledge of the interaction of light antinuclei with matter is limited. We determine the disappearance probability of $^{3}\overline{\rm He}$ when it encounters matter particles and annihilates or disintegrates within the ALICE detector at the Large Hadron Collider. We extract the inelastic interaction cross section, which is then used as input to calculations of the transparency of our Galaxy to the propagation of $^{3}\overline{\rm He}$ stemming from dark-matter annihilation and cosmic-ray interactions within the interstellar medium. For a specific dark-matter profile, we estimate a transparency of about 50%, whereas it varies with increasing $^{3}\overline{\rm He}$ momentum from 25% to 90% for cosmic-ray sources. The results indicate that $^{3}\overline{\rm He}$ nuclei can travel long distances in the Galaxy, and can be used to study cosmic-ray interactions and dark-matter annihilation.

21 data tables

Raw primary antihelium3-to-helium3 ratio as a function of the momentum p_primary.

Raw primary antihelium3-to-helium3 ratio from Geant4-based MC simulations as a function of the momentum p_primary with default sigma_inel(3Hebar).

Raw primary antihelium3-to-helium3 ratio from Geant4-based MC simulations as a function of the momentum p_primary with sigma_inel(3Hebar)x0.5.

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Two-particle Bose-Einstein correlations in pp collisions at ${\sqrt{s} = 13}$ TeV measured with the ATLAS detector at the LHC

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Eur.Phys.J.C 82 (2022) 608, 2022.
Inspire Record 2027827 DOI 10.17182/hepdata.132012

This paper presents studies of Bose-Einstein correlations (BEC) in proton-proton collisions at a centre-of-mass energy of 13 TeV, using data from the ATLAS detector at the CERN Large Hadron Collider. Data were collected in a special low-luminosity configuration with a minimum-bias trigger and a high-multiplicity track trigger, accumulating integrated luminosities of 151 $\mu$b$^{-1}$ and 8.4 nb$^{-1}$ respectively. The BEC are measured for pairs of like-sign charged particles, each with $|\eta|$ < 2.5, for two kinematic ranges: the first with particle $p_T$ > 100 MeV and the second with particle $p_T$ > 500 MeV. The BEC parameters, characterizing the source radius and particle correlation strength, are investigated as functions of charged-particle multiplicity (up to 300) and average transverse momentum of the pair (up to 1.5 GeV). The double-differential dependence on charged-particle multiplicity and average transverse momentum of the pair is also studied. The BEC radius is found to be independent of the charged-particle multiplicity for high charged-particle multiplicity (above 100), confirming a previous observation at lower energy. This saturation occurs independent of the transverse momentum of the pair.

154 data tables

Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the opposite hemisphere (OHP) like-charge particles pairs reference sample for k<sub>T</sub> - interval 1000 &lt; k<sub>T</sub> &le; 1500&nbsp;MeV.

Comparison of single-ratio two-particle correlation functions, C<sub>2</sub><sup>data</sup>(Q) and C<sub>2</sub><sup>MC</sup>(Q), with the two-particle double-ratio correlation function, R<sub>2</sub>(Q), for the high-multiplicity track (HMT) events using the unlike-charge particle (UCP) pairs reference sample for k<sub>T</sub> - interval 1000 &lt; k<sub>T</sub> &le; 1500&nbsp;MeV.

The Bose-Einstein correlation (BEC) parameter R as a function of n<sub>ch</sub> for MB events using different MC generators in the calculation of R<sub>2</sub>(Q). The uncertainties shown are statistical. The lower panel of each plot shows the ratio of the BEC parameters obtained using EPOS LHC (red circles), Pythia 8 Monash (blue squares) and Herwig++ UE-EE-5 (green triangles) compared with the parameters obtained using Pythia 8 A2. The gray band in the lower panels is the MC systematic uncertainty, obtained as explained in the text.

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Search for type-III seesaw heavy leptons in leptonic final states in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Eur.Phys.J.C 82 (2022) 988, 2022.
Inspire Record 2027687 DOI 10.17182/hepdata.114228

A search for the pair production of heavy leptons as predicted by the type-III seesaw mechanism is presented. The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to 139 fb$^{-1}$ of integrated luminosity recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. The analysis focuses on final states with three or four electrons or muons from the possible decays of new heavy leptons via intermediate electroweak bosons. No significant deviations above the Standard Model expectation are observed; upper and lower limits on the heavy lepton production cross-section and masses are derived respectively. These results are then combined for the first time with the ones already published by ATLAS using the channel with two leptons in the final state. The observed lower limit on the mass of the type-III seesaw heavy leptons combining two, three and four lepton channels together is 910 GeV at the 95% confidence level.

25 data tables

Expected background yields and observed data after the background-only fit in the SRs.

Distribution of $m_{\mathrm{T},3l}$ in the ZL SR after the background-only fit. The uncertainty on the expected number of background events includes all statistical and systematic post-fit uncertainties with the correlations between various background sources taken into account.

Distribution of $m_{\mathrm{T},3l}$ in the ZL Veto SR after the background-only fit. The uncertainty on the expected number of background events includes all statistical and systematic post-fit uncertainties with the correlations between various background sources taken into account.

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Measurement of the Higgs boson width and evidence of its off-shell contributions to ZZ production

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Nature Phys. 18 (2022) 1329-1334, 2022.
Inspire Record 2032090 DOI 10.17182/hepdata.127288

Since the discovery of the Higgs boson in 2012, detailed studies of its properties have been ongoing. Besides its mass, its width - related to its lifetime - is an important parameter. One way to determine this quantity is by measuring its off-shell production, where the Higgs boson mass is far away from its nominal value, and relating it to its on-shell production, where the mass is close to the nominal value. Here, we report evidence for such off-shell contributions to the production cross section of two Z bosons with data from the CMS experiment at the CERN Large Hadron Collider. We constrain the total rate of the off-shell Higgs boson contribution beyond the Z boson pair production threshold, relative to its standard model expectation, to the interval [0.0061, 2.0] at 95% confidence level. The scenario with no off-shell contribution is excluded at a $p$-value of 0.0003 (3.6 standard deviations). We measure the width of the Higgs boson as $\Gamma_{\mathrm{H}}$ = 3.2 $_{-1.7}^{+2.4}$ MeV, in agreement with the standard model expectation of 4.1 MeV. In addition, we set constraints on anomalous Higgs boson couplings to W and Z boson pairs.

47 data tables

GGsm vs -2dNLL (SM-like (f_{ai}=0) observed)

GGsm vs -2dNLL (f_{a2} (u) observed)

GGsm vs -2dNLL (f_{a3} (u) observed)

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Version 3
Search for resonant pair production of Higgs bosons in the $b\bar{b}b\bar{b}$ final state using $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Phys.Rev.D 105 (2022) 092002, 2022.
Inspire Record 2032611 DOI 10.17182/hepdata.111124

A search for resonant Higgs boson pair production in the $b\bar{b}b\bar{b}$ final state is presented. The analysis uses 126-139 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}$ = 13 TeV collected with the ATLAS detector at the Large Hadron Collider. The analysis is divided into two channels, targeting Higgs boson decays which are reconstructed as pairs of small-radius jets or as individual large-radius jets. Spin-0 and spin-2 benchmark signal models are considered, both of which correspond to resonant $HH$ production via gluon$-$gluon fusion. The data are consistent with Standard Model predictions. Upper limits are set on the production cross-section times branching ratio to Higgs boson pairs of a new resonance in the mass range from 251 GeV to 5 TeV.

20 data tables

Cumulative acceptance times efficiency as a function of resonance mass for each event selection step in the resolved channel for the spin-0 signal models. The local maximum at 251 GeV is a consequence of the near-threshold kinematics.

Cumulative acceptance times efficiency as a function of resonance mass for each event selection step in the resolved channel for the spin-2 signal models. The local maximum at 251 GeV is a consequence of the near-threshold kinematics.

Corrected $m(HH)$ distribution in the resolved $4b$ validation region (dots), compared with the reweighted distribution in $2b$ validation region (teal histogram). The error bars on the $4b$ points represent the Poisson uncertainties corresponding to their event yields. The final bin includes overflow. The background uncertainty (gray band) is computed by adding all individual components in quadrature. The bottom panel shows the difference between the $4b$ and reweighted $2b$ distributions, relative to the $2b$ distribution.

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Search for invisible Higgs-boson decays in events with vector-boson fusion signatures using 139 $\text{fb}^{-1}$ of proton-proton data recorded by the ATLAS experiment

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
JHEP 08 (2022) 104, 2022.
Inspire Record 2033393 DOI 10.17182/hepdata.127760

A direct search for Higgs bosons produced via vector-boson fusion and subsequently decaying into invisible particles is reported. The analysis uses 139 $\text{fb}^{-1}$ of $pp$ collision data at a centre-of-mass energy of $\sqrt{s}$=13 $\text{TeV}$ recorded by the ATLAS detector at the LHC. The observed numbers of events are found to be in agreement with the background expectation from Standard Model processes. For a scalar Higgs boson with a mass of 125 $\text{GeV}$ and a Standard Model production cross section, an observed upper limit of $0.145$ is placed on the branching fraction of its decay into invisible particles at 95% confidence level, with an expected limit of $0.103$. These results are interpreted in the context of models where the Higgs boson acts as a portal to dark matter, and limits are set on the scattering cross section of weakly interacting massive particles and nucleons. Invisible decays of additional scalar bosons with masses from 50 $\text{GeV}$ to 2 $\text{TeV}$ are also studied, and the derived upper limits on the cross section times branching fraction decrease with increasing mass from 1.0 $\text{pb}$ for a scalar boson mass of 50 $\text{GeV}$ to 0.1 $\text{pb}$ at a mass of 2 $\text{TeV}$.

1 data table

Yields after each selection criterion for a signal sample of an invisibly decaying Higgs boson produced in VBF and ggF for 139 $fb^{-1}$ of data. The lines 'Timing of j1/j2' are referring to requirements that are part of the jet cleaning, and which ensure that the timing of the two leading jets is compatible with the bunch crossing. The last sixteen rows show the yield in each SR bin and the efficiency with respect to the inclusive signal region.


Version 2
Inclusive nonresonant multilepton probes of new phenomena at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Phys.Rev.D 105 (2022) 112007, 2022.
Inspire Record 2034279 DOI 10.17182/hepdata.110691

An inclusive search for nonresonant signatures of beyond the standard model (SM) phenomena in events with three or more charged leptons, including hadronically decaying $\tau$ leptons, is presented. The analysis is based on a data sample corresponding to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at $\sqrt{s} =$ 13 TeV, collected by the CMS experiment at the LHC in 2016-2018. Events are categorized based on the lepton and b-tagged jet multiplicities and various kinematic variables. Three scenarios of physics beyond the SM are probed, and signal-specific boosted decision trees are used for enhancing sensitivity. No significant deviations from the background expectations are observed. Lower limits are set at 95% confidence level on the mass of type-III seesaw heavy fermions in the range 845-1065 GeV for various decay branching fraction combinations to SM leptons. Doublet and singlet vector-like $\tau$ lepton extensions of the SM are excluded for masses below 1045 GeV and in the mass range 125-150 GeV, respectively. Scalar leptoquarks decaying exclusively to a top quark and a lepton are excluded below 1.12-1.42 TeV, depending on the lepton flavor. For the type-III seesaw as well as the vector-like doublet model, these constraints are the most stringent to date. For the vector-like singlet model, these are the first constraints from the LHC experiments. Detailed results are also presented to facilitate alternative theoretical interpretations.

288 data tables

The minimum lepton $\mathrm{p_{T}}$ (GeV) distribution in 3L MisID CR events for the combined 2016-2018 data set. The rightmost bin contains the overflow events. The lower panel shows the ratio of observed events to the total expected background prediction. The gray band on the ratio represents the sum of statistical and systematic uncertainties in the SM background prediction.

The $\mathrm{S_{T}}$ (GeV) distribution in 3L WZ CR events for the combined 2016-2018 data set. The rightmost bin contains the overflow events. The lower panel shows the ratio of observed events to the total expected background prediction. The gray band on the ratio represents the sum of statistical and systematic uncertainties in the SM background prediction.

The $\mathrm{DR_{min}}$ distribution in 3L Z$\mathrm{\gamma}$ CR events for the combined 2016-2018 data set. The rightmost bin contains the overflow events. The lower panel shows the ratio of observed events to the total expected background prediction. The gray band on the ratio represents the sum of statistical and systematic uncertainties in the SM background prediction.

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Search for Higgs boson pair production in the four b quark final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
Phys.Rev.Lett. 129 (2022) 081802, 2022.
Inspire Record 2035644 DOI 10.17182/hepdata.114358

A search for pairs of Higgs bosons produced via gluon and vector boson fusion is presented, focusing on the four b quark final state. The data sample consists of proton-proton collisions at a center-of-mass energy of 13 TeV, collected with the CMS detector at the LHC, and corresponds to an integrated luminosity of 138 fb$^{-1}$. No deviation from the background-only hypothesis is observed. A 95% confidence level upper limit on the Higgs boson pair production cross section is observed at 3.9 times the standard model prediction for an expected value of 7.8. Constraints are also set on the modifiers of the Higgs field self-coupling, $\kappa_\lambda$, and of the coupling of two Higgs bosons to two vector bosons, $\kappa_\mathrm{2V}$. The observed (expected) allowed intervals at the 95% confidence level are $-$2.3 $\lt$ $\kappa_\lambda$ $\lt$ 9.4 ($-$5.0 $\lt$ $\kappa_\lambda$ $\lt$ 12.0) and $-$0.1 $\lt$ $\kappa_\mathrm{2V}$ $\lt$ 2.2 ($-$0.4 $\lt$ $\kappa_\mathrm{2V}$ $\lt$ 2.5). These are the most stringent observed constraints to date on the HH production cross section and on the $\kappa_\mathrm{2V}$ coupling.

2 data tables

Observed and expected 95% CL upper limits on cross section as a function of $\kappa_{\lambda}$ modifier

Observed and expected 95% CL upper limits on cross section as a function of $\kappa_{2V}$ modifier


Nuclear modification of $\Upsilon$ states in pPb collisions at $\sqrt{s_\mathrm{NN}}$ = 5.02 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Ambrogi, Federico ; et al.
Phys.Lett.B 835 (2022) 137397, 2022.
Inspire Record 2037640 DOI 10.17182/hepdata.88291

Production cross sections of $\Upsilon$(1S), $\Upsilon$(2S), and $\Upsilon$(3S) states decaying into $\mu^+\mu^-$ in proton-lead (pPb) collisions are reported using data collected by the CMS experiment at $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. A comparison is made with corresponding cross sections obtained with pp data measured at the same collision energy and scaled by the Pb nucleus mass number. The nuclear modification factor for $\Upsilon$(1S) is found to be $R_\mathrm{pPb}(\Upsilon(1S))$ = 0.806 $\pm$ 0.024 (stat) $\pm$ 0.059 (syst). Similar results for the excited states indicate a sequential suppression pattern, such that $R_\mathrm{pPb}(\Upsilon(1S))$$\gt$$R_\mathrm{pPb}(\Upsilon(2S))$$\gt$$R_\mathrm{pPb}(\Upsilon(3S))$. The suppression is much less pronounced in pPb than in PbPb collisions, and independent of transverse momentum $p_\mathrm{T}^\Upsilon$ and center-of-mass rapidity $y_\mathrm{CM}^\Upsilon$ of the individual $\Upsilon$ state in the studied range $p_\mathrm{T}^\Upsilon$$\lt$ 30 GeV$/c$ and $\vert y_\mathrm{CM}^\Upsilon\vert$$\lt$ 1.93. Models that incorporate sequential suppression of bottomonia in pPb collisions are in better agreement with the data than those which only assume initial-state modifications.

31 data tables

Differential cross section times dimuon branching fraction of Y(1S) as a function of pT in pPb collisions. The global uncertainty arises from the integrated luminosity uncertainty in pPb collisions.

Differential cross section times dimuon branching fraction of Y(2S) as a function of pT in pPb collisions. The global uncertainty arises from the integrated luminosity uncertainty in pPb collisions.

Differential cross section times dimuon branching fraction of Y(3S) as a function of pT in pPb collisions. The global uncertainty arises from the integrated luminosity uncertainty in pPb collisions.

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Measurement of the Drell-Yan forward-backward asymmetry at high dilepton masses in proton-proton collisions at $\sqrt{s}$ = 13 TeV

The CMS collaboration Tumasyan, Armen ; Adam, Wolfgang ; Andrejkovic, Janik Walter ; et al.
JHEP 2022 (2022) 063, 2022.
Inspire Record 2038801 DOI 10.17182/hepdata.114012

A measurement of the forward-backward asymmetry of pairs of oppositely charged leptons (dimuons and dielectrons) produced by the Drell-­Yan process in proton-proton collisions is presented. The data sample corresponds to an integrated luminosity of 138 fb$^{-1}$ collected with the CMS detector at the LHC at a center-of-mass energy of 13 TeV. The asymmetry is measured as a function of lepton pair mass for masses larger than 170\GeV and compared with standard model predictions. An inclusive measurement across both channels and the full mass range yields an asymmetry of 0.599 $\pm$ 0.005 (stat) $\pm$ 0.007 (syst). As a test of lepton flavor universality, the difference between the dimuon and dielectron asymmetries is measured as well. No statistically significant deviations from standard model predictions are observed. The measurements are used to set limits on the presence of additional gauge bosons. For a Z' in the sequential standard model, a lower mass limit of 4.4 TeV is set at 95% confidence level.

5 data tables

Results for the measurement of $A_\mathrm{FB}$ from the maximum likelihood fit to data in different dilepton mass bins in the different channels as well as an inclusive measurement across all mass bins.

Results for the measurement of $A_0$ from the maximum likelihood fit to data in different dilepton mass bins in the different channels as well as inclusive measurement across all mass bins. To help in the interpretation of these results, we also list the average dilepton $p_{T}$ of the data events in each mass bin.

Results for the measurement of $\Delta A_\mathrm{FB}$ and $\Delta A_0$ between the muon and electron channels from the maximum likelihood fit to data in different mass bins as well as an inclusive measurement across all mass bins.

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