Date

Flow and interferometry results from Au+Au collisions at $\sqrt{\textit{s}_{NN}}$ = 4.5 GeV

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.
Phys.Rev.C 103 (2021) 034908, 2021.
Inspire Record 1809043 DOI 10.17182/hepdata.95903

The Beam Energy Scan (BES) program at the Relativistic Heavy Ion Collider (RHIC) was extended to energies below $\sqrt{\textit{s}_{NN}}$ = 7.7 GeV in 2015 by successful implementation of the fixed-target mode of operation in the STAR (Solenoidal Track At RHIC) experiment. In the fixed-target mode, ions circulate in one ring of the collider and interact with a stationary target at the entrance of the STAR Time Projection Chamber. The first results for Au+Au collisions at $\sqrt{\textit{s}_{NN}}$ = 4.5 GeV are presented, including directed and elliptic flow of identified hadrons, and radii from pion femtoscopy. The proton flow and pion femtoscopy results agree quantitatively with earlier measurements by Alternating Gradient Synchrotron experiments at similar energies. This validates running the STAR experiment in the fixed-target configuration. Pion directed and elliptic flow are presented for the first time at this beam energy. Pion and proton elliptic flow show behavior which hints at constituent quark scaling, but large error bars preclude reliable conclusions. The ongoing second phase of BES (BES-II) will provide fixed-target data sets with 100 times more events at each of several energies down to $\sqrt{\textit{s}_{NN}}$ = 3.0 GeV.

12 data tables

Centrality selection for STAR FXT sqrt(sNN) = 4.5 GeV Au+Au collisions

Rapidity dependence of directed flow, v1(y), for protons with transverse momentum 0.4 < pT < 2.0 GeV/c from events with 10-25% centrality.

Rapidity dependence of directed flow, v1(y), for negative pions with transverse momentum pT > 0.2 GeV/c and total momentum magnitude |p| < 1.6 GeV/c from events within 10-30% centrality. Here, the BBC-based Event Plane method is used. Plotted error bars are statistical only, and systematic errors are of comparable size.

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Test of the universality of $\tau$ and $\mu$ lepton couplings in $W$-boson decays from $t\bar{t}$ events with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Brad ; Abbott, Dale Charles ; et al.
Nature Phys. 17 (2021) 813-818, 2021.
Inspire Record 1885958 DOI 10.17182/hepdata.100232

The Standard Model of particle physics encapsulates our current best understanding of physics at the smallest scales. A fundamental axiom of this theory is the universality of the couplings of the different generations of leptons to the electroweak gauge bosons. The measurement of the ratio of the rate of decay of $W$ bosons to $\tau$-leptons and muons, $R(\tau/\mu) = B(W \to \tau \nu_\tau)/B(W \to \mu \nu_\mu)$, constitutes an important test of this axiom. A measurement of this quantity with a novel technique using di-leptonic $t\bar{t}$ events is presented based on 139 fb${}^{-1}$ of data recorded with the ATLAS detector in proton--proton collisions at $\sqrt{s}=13$ TeV. Muons originating from $W$ bosons and those originating from an intermediate $\tau$-lepton are distinguished using the lifetime of the $\tau$-lepton, through the muon transverse impact parameter, and differences in the muon transverse momentum spectra. The value of $R(\tau/\mu)$ is found to be $0.992 \pm 0.013 [\pm 0.007 (stat) \pm 0.011 (syst)]$ and is in agreement with the hypothesis of universal lepton couplings as postulated in the Standard Model. This is the most precise measurement of this ratio, and the only such measurement from the Large Hadron Collider, to date.

7 data tables

The number of data and fitted simulated events in each bin of the $|d_{0}^{\mu}|$ distribution in the $5<p_{\textrm{T}}^{\mu}<10$ GeV selection in the $e-\mu$ channel.

The number of data and fitted simulated events in each bin of the $|d_{0}^{\mu}|$ distribution in the $5<p_{\textrm{T}}^{\mu}<10$ GeV selection in the $\mu-\mu$ channel.

The number of data and fitted simulated events in each bin of the $|d_{0}^{\mu}|$ distribution in the $10<p_{\textrm{T}}^{\mu}<20$ GeV selection in the $e-\mu$ channel.

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Global polarization of $\Xi$ and $\Omega$ hyperons in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.
Phys.Rev.Lett. 126 (2021) 162301, 2021.
Inspire Record 1838481 DOI 10.17182/hepdata.100234

Global polarization of $\Xi$ and $\Omega$ hyperons has been measured for the first time in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV. The measurements of the $\Xi^-$ and $\bar{\Xi}^+$ hyperon polarization have been performed by two independent methods, via analysis of the angular distribution of the daughter particles in the parity violating weak decay $\Xi\rightarrow\Lambda+\pi$, as well as by measuring the polarization of the daughter $\Lambda$-hyperon, polarized via polarization transfer from its parent. The polarization, obtained by combining the results from the two methods and averaged over $\Xi^-$ and $\bar{\Xi}^+$, is measured to be $\langle P_\Xi \rangle = 0.47\pm0.10~({\rm stat.})\pm0.23~({\rm syst.})\,\%$ for the collision centrality 20%-80%. The $\langle P_\Xi \rangle$ is found to be slightly larger than the inclusive $\Lambda$ polarization and in reasonable agreement with a multi-phase transport model (AMPT). The $\langle P_\Xi \rangle$ is found to follow the centrality dependence of the vorticity predicted in the model, increasing toward more peripheral collisions. The global polarization of $\Omega$, $\langle P_\Omega \rangle = 1.11\pm0.87~({\rm stat.})\pm1.97~({\rm syst.})\,\%$ was obtained by measuring the polarization of daughter $\Lambda$ in the decay $\Omega \rightarrow \Lambda + K$, assuming the polarization transfer factor $C_{\Omega\Lambda}=1$.

4 data tables

$\Xi$ and $\Omega$ global polarization in Au+Au collisions at 200 GeV. Decay parameter from PDG2020, $\alpha_{\Xi}$=-$\alpha_{\bar{\Xi}}$=-0.401, is used.

The energy dependence of $\Lambda$ and $\bar{\Lambda}$ global polarization. Note that the results from previous measurements are rescaled using updated decay parameters (PDG2020), $\alpha_{\Lambda}$=0.732 and $\alpha_{\bar{\Lambda}}$=-0.758. The original data can be found in <a href="https://www.hepdata.net/record/ins1510474">this page</a>.

Centrality dependence of $\Xi$ global poalrization in Au+Au collisions at 200 GeV. Decay parameter from PDG2020, $\alpha_{\Xi}$=-$\alpha_{\bar{\Xi}}$=-0.401, is used.

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Observation of $D_{s}^{\pm}/D^0$ enhancement in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV

The STAR collaboration Adam, J. ; Adamczyk, L. ; Adams, J.R. ; et al.
Phys.Rev.Lett. 127 (2021) 092301, 2021.
Inspire Record 1843268 DOI 10.17182/hepdata.101172

We report on the first measurement of charm-strange meson $D_s^{\pm}$ production at midrapidity in Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV from the STAR experiment. The yield ratio between strange ($D_{s}^{\pm}$) and non-strange ($D^{0}$) open-charm mesons is presented and compared to model calculations. A significant enhancement, relative to a PYTHIA simulation of $p$+$p$ collisions, is observed in the $D_{s}^{\pm}/D^0$ yield ratio in Au+Au collisions over a large range of collision centralities. Model calculations incorporating abundant strange-quark production in the quark-gluon plasma (QGP) and coalescence hadronization qualitatively reproduce the data. The transverse-momentum integrated yield ratio of $D_{s}^{\pm}/D^0$ at midrapidity is consistent with a prediction from a statistical hadronization model with the parameters constrained by the yields of light and strange hadrons measured at the same collision energy. These results suggest that the coalescence of charm quarks with strange quarks in the QGP plays an important role in $D_{s}^{\pm}$ meson production in heavy-ion collisions.

10 data tables

The $KK\pi$ invariant mass distribution (Counts per 8 MeV/$c^{2}$ bin) for right-sign combinations in 0-80% Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV.

$D_s^{\pm}$ invariant yield as a function of $p_{T}$ in 0-10% centrality bin of Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV. The $p_T$ bins are 1.5 < $p_T$ < 2.5 GeV/c, 2.5 < $p_T$ < 3.5 GeV/c, 3.5 < $p_T$ < 5.0 GeV/c and 5.0 < $p_T$ < 8.0 GeV/c.

$D_s^{\pm}$ invariant yield as a function of $p_{T}$ in 10-40% centrality bin of Au+Au collisions at $\sqrt{s_{_{\rm NN}}}$ = 200 GeV. The $p_T$ bins are 1.0 < $p_T$ < 2.0 GeV/c, 2.0 < $p_T$ < 2.5 GeV/c, 2.5 < $p_T$ < 3.5 GeV/c, 3.5 < $p_T$ < 5.0 GeV/c and 5.0 < $p_T$ < 8.0 GeV/c.

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Evidence for X(3872) in PbPb collisions and studies of its prompt production at $\sqrt{s_\mathrm{NN}}=$ 5.02 TeV

The CMS collaboration Sirunyan, Albert M. ; Tumasyan, Armen ; Adam, Wolfgang ; et al.
Phys.Rev.Lett. 128 (2022) 032001, 2022.
Inspire Record 1848438 DOI 10.17182/hepdata.93882

The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (PbPb) collisions at a center-of-mass energy of $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV per nucleon pair, using the decay chain X(3872) $\to$ J$/\psi\, \pi^+\pi^- \to$ $\mu^+\mu^-\pi^+\pi^-$. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of 1.7 nb$^{-1}$. The measurement is performed in the rapidity and transverse momentum ranges $|y|$ $\lt$ 1.6 and 15 $\lt$ $p_\mathrm{T}$ $\lt$ 50 GeV$/c$. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to $\psi$(2S) yield ratio is found to be $\rho^\mathrm{PbPb} = $ 1.08 $\pm$ 0.49 (stat) $\pm$ 0.52 (syst), to be compared with typical values of 0.1 for pp collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.

1 data table

The yield ratio $\rho^{\mathrm{PbPb}}$ of prompt X(3872) over $\psi(\mathrm{2S})$ production in PbPb collisions at 5.02 TeV


Longitudinal double-spin asymmetry for inclusive jet and dijet production in polarized proton collisions at $\sqrt{s}=200$ GeV

The STAR collaboration Abdallah, M.S. ; Adam, J. ; Adamczyk, L. ; et al.
Phys.Rev.D 103 (2021) L091103, 2021.
Inspire Record 1850855 DOI 10.17182/hepdata.104836

We report high-precision measurements of the longitudinal double-spin asymmetry, $A_{LL}$, for midrapidity inclusive jet and dijet production in polarized $pp$ collisions at a center-of-mass energy of $\sqrt{s}=200\,\mathrm{GeV}$. The new inclusive jet data are sensitive to the gluon helicity distribution, $\Delta g(x,Q^2)$, for gluon momentum fractions in the range from $x \simeq 0.05$ to $x \simeq 0.5$, while the new dijet data provide further constraints on the $x$ dependence of $\Delta g(x,Q^2)$. The results are in good agreement with previous measurements at $\sqrt{s}=200\,\mathrm{GeV}$ and with recent theoretical evaluations of prior world data. Our new results have better precision and thus strengthen the evidence that $\Delta g(x,Q^2)$ is positive for $x > 0.05$.

21 data tables

Jet yield versus jet transverse momentum $p_{T}$ at the detector level and at the parton level. Table includes data for the JP2 trigger conditions and the corresponding simulations.

Jet yield versus jet transverse momentum $p_{T}$ at the detector level and at the parton level. Table includes data for the JP1 trigger conditions and the corresponding simulations.

Dijet yield versus the dijet $M_{inv}$ at the detector level and at the parton level. Table includes data for the JP1 and JP2 trigger conditions and the corresponding simulations.

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Precise determination of the B0s-B0sbar oscillation frequency

The LHCb collaboration Aaij, R. ; Beteta, C. Abellán ; Ackernley, T. ; et al.
Nature Phys. 18 (2022) 1-5, 2022.
Inspire Record 1857623 DOI 10.17182/hepdata.105881

Mesons comprising a beauty quark and a strange quark can oscillate between particle (B0s) and antiparticle (B0s) flavour eigenstates, with a frequency given by the mass difference between heavy and light mass eigenstates, deltams. Here we present ameasurement of deltams using B0s2DsPi decays produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The oscillation frequency is found to be deltams = 17.7683 +- 0.0051 +- 0.0032 ps-1, where the first uncertainty is statistical and the second systematic. This measurement improves upon the current deltams precision by a factor of two. We combine this result with previous LHCb measurements to determine deltams = 17.7656 +- 0.0057 ps-1, which is the legacy measurement of the original LHCb detector.

1 data table

Summary of LHCb measurements. Comparison of LHCb $\Delta m_s$ measurements from Refs. [8–11], the result presented in this article and their average. For the average, following systematic uncertainties are assumed to be fully correlated(:) zScale, MomentumScale, VeloAlignment and DecayTimeBias. The measurements are statistically uncorrelated.


Version 3
Search for long-lived particles decaying to jets with displaced vertices in proton-proton collisions at $\sqrt{s}=$ 13 TeV

The CMS collaboration Sirunyan, A.M. ; Tumasyan, A. ; Adam, W. ; et al.
Phys.Rev.D 104 (2021) 052011, 2021.
Inspire Record 1861146 DOI 10.17182/hepdata.102798

A search is presented for long-lived particles produced in pairs in proton-proton collisions at the LHC operating at a center-of-mass energy of 13 TeV. The data were collected with the CMS detector during the period from 2015 through 2018, and correspond to a total integrated luminosity of 140 fb$^{-1}$. This search targets pairs of long-lived particles with mean proper decay lengths between 0.1 and 100 mm, each of which decays into at least two quarks that hadronize to jets, resulting in a final state with two displaced vertices. No significant excess of events with two displaced vertices is observed. In the context of $R$-parity violating supersymmetry models, the pair production of long-lived neutralinos, gluinos, and top squarks is excluded at 95% confidence level for cross sections larger than 0.08 fb, masses between 800 and 3000 GeV, and mean proper decay lengths between 1 and 25 mm.

32 data tables

Event yields in the control samples in data. The ''one-vertex'' events correspond to events containing exactly one vertex with the specified number of tracks. The ''two-vertex'' events have two or more vertices containing the specified numbers of tracks. We seek the signal in the $\geq$5-track two-vertex sample.

The distribution of distances between vertices in the $x$-$y$ plane, $d_{\mathrm{VV}}$, for three simulated multijet signals each with a mass of 1600 GeV, with the background template distribution overlaid. The production cross section for each signal model is assumed to be the lower limit excluded by CMS-EXO-17-018, corresponding to values of 0.8, 0.25, and 0.15 fb for the samples with $c\tau =$ 0.3, 1.0, and 10 mm, respectively. The last bin includes the overflow events. The two vertical pink dashed lines separate the regions used in the fit.

Multijet signal efficiencies as a function of the signal mass and lifetime for events satisfying all event and vertex requirements, with corrections based on systematic differences in the vertex reconstruction efficiency between data and simulation.

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Version 2
Search for chargino--neutralino pair production in final states with three leptons and missing transverse momentum in $\sqrt{s} = 13$ TeV $pp$ collisions with the ATLAS detector

The ATLAS collaboration Aad, Georges ; Abbott, Braden Keim ; Abbott, Dale ; et al.
Eur.Phys.J.C 81 (2021) 1118, 2021.
Inspire Record 1866951 DOI 10.17182/hepdata.95751

A search for chargino$-$neutralino pair production in three-lepton final states with missing transverse momentum is presented. The study is based on a dataset of $\sqrt{s} = 13$ TeV $pp$ collisions recorded with the ATLAS detector at the LHC, corresponding to an integrated luminosity of 139 fb$^{-1}$. No significant excess relative to the Standard Model predictions is found in data. The results are interpreted in simplified models of supersymmetry, and statistically combined with results from a previous ATLAS search for compressed spectra in two-lepton final states. Various scenarios for the production and decay of charginos ($\tilde\chi^\pm_1$) and neutralinos ($\tilde\chi^0_2$) are considered. For pure higgsino $\tilde\chi^\pm_1\tilde\chi^0_2$ pair-production scenarios, exclusion limits at 95% confidence level are set on $\tilde\chi^0_2$ masses up to 210 GeV. Limits are also set for pure wino $\tilde\chi^\pm_1\tilde\chi^0_2$ pair production, on $\tilde\chi^0_2$ masses up to 640 GeV for decays via on-shell $W$ and $Z$ bosons, up to 300 GeV for decays via off-shell $W$ and $Z$ bosons, and up to 190 GeV for decays via $W$ and Standard Model Higgs bosons.

132 data tables

This is the HEPData space for the ATLAS SUSY EWK three-lepton search. The full resolution figures can be found at https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2019-09/ The full statistical likelihoods have been provided for this analysis. They can be downloaded by clicking on the purple 'Resources' button above and selecting the 'Common Resources' category. <b>Region yields:</b> <ul display="inline-block"> <li><a href="?table=Tab%2012%20Onshell%20WZ%20Signal%20Region%20Yields%20Table">Tab 12 Onshell WZ Signal Region Yields Table</a> <li><a href="?table=Tab%2013%20Onshell%20Wh%20Signal%20Region%20Yields%20Table">Tab 13 Onshell Wh Signal Region Yields Table</a> <li><a href="?table=Tab%2014%20Offshell%20low-$E_{T}^{miss}$%20Signal%20Region%20Yields%20Table">Tab 14 Offshell low-$E_{T}^{miss}$ Signal Region Yields Table</a> <li><a href="?table=Tab%2015%20Offshell%20high-$E_{T}^{miss}$%20Signal%20Region%20Yields%20Table">Tab 15 Offshell high-$E_{T}^{miss}$ Signal Region Yields Table</a> <li><a href="?table=Tab%2020%20RJR%20Signal%20Region%20Yields%20Table">Tab 20 RJR Signal Region Yields Table</a> <li><a href="?table=Fig%204%20Onshell%20Control%20and%20Validation%20Region%20Yields">Fig 4 Onshell Control and Validation Region Yields</a> <li><a href="?table=Fig%208%20Offshell%20Control%20and%20Validation%20Region%20Yields">Fig 8 Offshell Control and Validation Region Yields</a> <li><a href="?table=Fig%2010%20Onshell%20WZ%20Signal%20Region%20Yields">Fig 10 Onshell WZ Signal Region Yields</a> <li><a href="?table=Fig%2011%20Onshell%20Wh%20Signal%20Region%20Yields">Fig 11 Onshell Wh Signal Region Yields</a> <li><a href="?table=Fig%2012%20Offshell%20Signal%20Region%20Yields">Fig 12 Offshell Signal Region Yields</a> <li><a href="?table=Fig%2018%20RJR%20Control%20and%20Validation%20Region%20Yields">Fig 18 RJR Control and Validation Region Yields</a> </ul> <b>Exclusion contours:</b> <ul display="inline-block"> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Obs">Fig 16a WZ Exclusion: Wino-bino(+), Obs</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Obs_Up">Fig 16a WZ Exclusion: Wino-bino(+), Obs_Up</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Obs_Down">Fig 16a WZ Exclusion: Wino-bino(+), Obs_Down</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Exp">Fig 16a WZ Exclusion: Wino-bino(+), Exp</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Exp_Up">Fig 16a WZ Exclusion: Wino-bino(+), Exp_Up</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20Exp_Down">Fig 16a WZ Exclusion: Wino-bino(+), Exp_Down</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20compressed_Obs">Fig 16a WZ Exclusion: Wino-bino(+), compressed_Obs</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20compressed_Exp">Fig 16a WZ Exclusion: Wino-bino(+), compressed_Exp</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20offshell_Obs">Fig 16a WZ Exclusion: Wino-bino(+), offshell_Obs</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20offshell_Exp">Fig 16a WZ Exclusion: Wino-bino(+), offshell_Exp</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20onshell_Obs">Fig 16a WZ Exclusion: Wino-bino(+), onshell_Obs</a> <li><a href="?table=Fig%2016a%20WZ%20Exclusion:%20Wino-bino(%2b),%20onshell_Exp">Fig 16a WZ Exclusion: Wino-bino(+), onshell_Exp</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Obs">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Obs</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Obs_Up">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Obs_Up</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Obs_Down">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Obs_Down</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Exp">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Exp</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Exp_Up">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Exp_Up</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20Exp_Down">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), Exp_Down</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20compressed_Obs">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), compressed_Obs</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20compressed_Exp">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), compressed_Exp</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20offshell_Obs">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), offshell_Obs</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20offshell_Exp">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), offshell_Exp</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20onshell_Obs">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), onshell_Obs</a> <li><a href="?table=Fig%2016b%20WZ%20Exclusion:%20Wino-bino(%2b)%20($\Delta%20m$),%20onshell_Exp">Fig 16b WZ Exclusion: Wino-bino(+) ($\Delta m$), onshell_Exp</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Obs">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Obs</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Obs_Up">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Obs_Up</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Obs_Down">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Obs_Down</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Exp">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Exp</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Exp_Up">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Exp_Up</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20Exp_Down">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), Exp_Down</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20compressed_Obs">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), compressed_Obs</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20compressed_Exp">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), compressed_Exp</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20offshell_Obs">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), offshell_Obs</a> <li><a href="?table=Fig%2016c%20WZ%20Exclusion:%20Wino-bino(-)%20($\Delta%20m$),%20offshell_Exp">Fig 16c WZ Exclusion: Wino-bino(-) ($\Delta m$), offshell_Exp</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Obs">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Obs</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Obs_Up">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Obs_Up</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Obs_Down">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Obs_Down</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Exp">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Exp</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Exp_Up">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Exp_Up</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20Exp_Down">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), Exp_Down</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20compressed_Obs">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), compressed_Obs</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20compressed_Exp">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), compressed_Exp</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20offshell_Obs">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), offshell_Obs</a> <li><a href="?table=Fig%2016d%20WZ%20Exclusion:%20Higgsino%20($\Delta%20m$),%20offshell_Exp">Fig 16d WZ Exclusion: Higgsino ($\Delta m$), offshell_Exp</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Obs">Fig 17 Wh Exclusion, Obs</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Obs_Up">Fig 17 Wh Exclusion, Obs_Up</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Obs_Down">Fig 17 Wh Exclusion, Obs_Down</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Exp">Fig 17 Wh Exclusion, Exp</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Exp_Up">Fig 17 Wh Exclusion, Exp_Up</a> <li><a href="?table=Fig%2017%20Wh%20Exclusion,%20Exp_Down">Fig 17 Wh Exclusion, Exp_Down</a> </ul> <b>Upper limits:</b> <ul display="inline-block"> <li><a href="?table=AuxFig%208a%20WZ%20Excl.%20Upper%20Limit%20Obs.%20Wino-bino(%2b)%20($\Delta%20m$)">AuxFig 8a WZ Excl. Upper Limit Obs. Wino-bino(+) ($\Delta m$)</a> <li><a href="?table=AuxFig%208b%20WZ%20Excl.%20Upper%20Limit%20Exp.%20Wino-bino(%2b)%20($\Delta%20m$)">AuxFig 8b WZ Excl. Upper Limit Exp. Wino-bino(+) ($\Delta m$)</a> <li><a href="?table=AuxFig%208c%20WZ%20Excl.%20Upper%20Limit%20Obs.%20Wino-bino(%2b)%20($\Delta%20m$)">AuxFig 8c WZ Excl. Upper Limit Obs. Wino-bino(+) ($\Delta m$)</a> <li><a href="?table=AuxFig%208d%20WZ%20Excl.%20Upper%20Limit%20Exp.%20Wino-bino(%2b)%20($\Delta%20m$)">AuxFig 8d WZ Excl. Upper Limit Exp. Wino-bino(+) ($\Delta m$)</a> <li><a href="?table=AuxFig%208e%20WZ%20Excl.%20Upper%20Limit%20Obs.%20Wino-bino(-)%20($\Delta%20m$)">AuxFig 8e WZ Excl. Upper Limit Obs. Wino-bino(-) ($\Delta m$)</a> <li><a href="?table=AuxFig%208f%20WZ%20Excl.%20Upper%20Limit%20Exp.%20Wino-bino(-)%20($\Delta%20m$)">AuxFig 8f WZ Excl. Upper Limit Exp. Wino-bino(-) ($\Delta m$)</a> <li><a href="?table=AuxFig%208g%20WZ%20Excl.%20Upper%20Limit%20Obs.%20Higgsino%20($\Delta%20m$)">AuxFig 8g WZ Excl. Upper Limit Obs. Higgsino ($\Delta m$)</a> <li><a href="?table=AuxFig%208h%20WZ%20Excl.%20Upper%20Limit%20Exp.%20Higgsino%20($\Delta%20m$)">AuxFig 8h WZ Excl. Upper Limit Exp. Higgsino ($\Delta m$)</a> <li><a href="?table=AuxFig%209a%20Wh%20Excl.%20Upper%20Limit%20Obs.">AuxFig 9a Wh Excl. Upper Limit Obs.</a> <li><a href="?table=AuxFig%209b%20Wh%20Excl.%20Upper%20Limit%20Exp.">AuxFig 9b Wh Excl. Upper Limit Exp.</a> </ul> <b>Model-independent discovery fits:</b> <ul display="inline-block"> <li><a href="?table=Tab%2018%20Onshell%20Discovery%20Fit%20Table">Tab 18 Onshell Discovery Fit Table</a> <li><a href="?table=Tab%2019%20Offshell%20Discovery%20Fit%20Table">Tab 19 Offshell Discovery Fit Table</a> <li><a href="?table=Tab%2021%20RJR%20Discovery%20Fit%20Table">Tab 21 RJR Discovery Fit Table</a> </ul> <b>Kinematic distributions:</b> <ul display="inline-block"> <li><a href="?table=Fig%2013a%20SR$_{DFOS}^{Wh}$-1%20($\Delta%20R_{OS,%20near}$)">Fig 13a SR$_{DFOS}^{Wh}$-1 ($\Delta R_{OS, near}$)</a> <li><a href="?table=Fig%2013b%20SR$_{DFOS}^{Wh}$-2%20(3rd%20Lep.%20$p_{T}$)">Fig 13b SR$_{DFOS}^{Wh}$-2 (3rd Lep. $p_{T}$)</a> <li><a href="?table=Fig%2013c%20SR$_{0j}^{WZ}$%20($E_{T}^{miss}$)">Fig 13c SR$_{0j}^{WZ}$ ($E_{T}^{miss}$)</a> <li><a href="?table=Fig%2013d%20SR$_{0j}^{WZ}$%20($m_{T}$)">Fig 13d SR$_{0j}^{WZ}$ ($m_{T}$)</a> <li><a href="?table=Fig%2014a%20SR$^{offWZ}_{LowETmiss}$-0j%20($m_{T}^{minmll}$)">Fig 14a SR$^{offWZ}_{LowETmiss}$-0j ($m_{T}^{minmll}$)</a> <li><a href="?table=Fig%2014b%20SR$^{offWZ}_{LowETmiss}$-nj%20($m_{T}^{minmll}$)">Fig 14b SR$^{offWZ}_{LowETmiss}$-nj ($m_{T}^{minmll}$)</a> <li><a href="?table=Fig%2014c%20SR$^{offWZ}_{HighETmiss}$-0j%20($m_{T}^{minmll}$)">Fig 14c SR$^{offWZ}_{HighETmiss}$-0j ($m_{T}^{minmll}$)</a> <li><a href="?table=Fig%2014d%20SR$^{offWZ}_{HighETmiss}$-nj%20($p_T^l%20\div%20E_T^{miss}$)">Fig 14d SR$^{offWZ}_{HighETmiss}$-nj ($p_T^l \div E_T^{miss}$)</a> <li><a href="?table=Fig%2020a%20RJR%20SR3$\ell$-Low%20($p_{T}^{\ell%201}$)">Fig 20a RJR SR3$\ell$-Low ($p_{T}^{\ell 1}$)</a> <li><a href="?table=Fig%2020b%20RJR%20SR3$\ell$-Low%20($H_{3,1}^{PP}$)">Fig 20b RJR SR3$\ell$-Low ($H_{3,1}^{PP}$)</a> <li><a href="?table=Fig%2020c%20RJR%20SR3$\ell$-ISR%20($p_{T~ISR}^{CM}$)">Fig 20c RJR SR3$\ell$-ISR ($p_{T~ISR}^{CM}$)</a> <li><a href="?table=Fig%2020d%20RJR%20SR3$\ell$-ISR%20($R_{ISR}$)">Fig 20d RJR SR3$\ell$-ISR ($R_{ISR}$)</a> </ul> <b>Cutflows:</b> <ul display="inline-block"> <li><a href="?table=AuxTab%205%20Cutflow:%20Onshell%20WZ">AuxTab 5 Cutflow: Onshell WZ</a> <li><a href="?table=AuxTab%206%20Cutflow:%20Onshell%20Wh">AuxTab 6 Cutflow: Onshell Wh</a> <li><a href="?table=AuxTab%207%20Cutflow:%20Offshell%20Wino-bino(%2b)%20(250,235)">AuxTab 7 Cutflow: Offshell Wino-bino(+) (250,235)</a> <li><a href="?table=AuxTab%208%20Cutflow:%20Offshell%20Wino-bino(%2b)%20(125,85)">AuxTab 8 Cutflow: Offshell Wino-bino(+) (125,85)</a> <li><a href="?table=AuxTab%209%20Cutflow:%20Offshell%20Wino-bino(%2b)%20(250,170)">AuxTab 9 Cutflow: Offshell Wino-bino(+) (250,170)</a> <li><a href="?table=AuxTab%2010%20Cutflow:%20Offshell%20Wino-bino(-)%20(250,235)">AuxTab 10 Cutflow: Offshell Wino-bino(-) (250,235)</a> <li><a href="?table=AuxTab%2011%20Cutflow:%20Offshell%20Wino-bino(-)%20(125,85)">AuxTab 11 Cutflow: Offshell Wino-bino(-) (125,85)</a> <li><a href="?table=AuxTab%2012%20Cutflow:%20Offshell%20Wino-bino(-)%20(250,170)">AuxTab 12 Cutflow: Offshell Wino-bino(-) (250,170)</a> <li><a href="?table=AuxTab%2013%20Cutflow:%20Offshell%20Higgsino%20(120,100)">AuxTab 13 Cutflow: Offshell Higgsino (120,100)</a> <li><a href="?table=AuxTab%2014%20Cutflow:%20Offshell%20Higgsino%20(100,40)">AuxTab 14 Cutflow: Offshell Higgsino (100,40)</a> <li><a href="?table=AuxTab%2015%20Cutflow:%20Offshell%20Higgsino%20(185,125)">AuxTab 15 Cutflow: Offshell Higgsino (185,125)</a> </ul> <b>Acceptances and Efficiencies:</b> <ul display="inline-block"> <li><a href="?table=AuxFig%2010a%20Acc:%20Onshell%20SR$_{0j}^{WZ}$">AuxFig 10a Acc: Onshell SR$_{0j}^{WZ}$</a> <li><a href="?table=AuxFig%2010b%20Eff:%20Onshell%20SR$_{0j}^{WZ}$">AuxFig 10b Eff: Onshell SR$_{0j}^{WZ}$</a> <li><a href="?table=AuxFig%2010c%20Acc:%20Onshell%20SR$_{nj}^{WZ}$">AuxFig 10c Acc: Onshell SR$_{nj}^{WZ}$</a> <li><a href="?table=AuxFig%2010d%20Eff:%20Onshell%20SR$_{nj}^{WZ}$">AuxFig 10d Eff: Onshell SR$_{nj}^{WZ}$</a> <li><a href="?table=AuxFig%2011a%20Acc:%20Onshell%20SR$_{low-m_{ll}-0j}^{Wh}$">AuxFig 11a Acc: Onshell SR$_{low-m_{ll}-0j}^{Wh}$</a> <li><a href="?table=AuxFig%2011b%20Eff:%20Onshell%20SR$_{low-m_{ll}-0j}^{Wh}$">AuxFig 11b Eff: Onshell SR$_{low-m_{ll}-0j}^{Wh}$</a> <li><a href="?table=AuxFig%2011c%20Acc:%20Onshell%20SR$_{low-m_{ll}-nj}^{Wh}$">AuxFig 11c Acc: Onshell SR$_{low-m_{ll}-nj}^{Wh}$</a> <li><a href="?table=AuxFig%2011d%20Eff:%20Onshell%20SR$_{low-m_{ll}-nj}^{Wh}$">AuxFig 11d Eff: Onshell SR$_{low-m_{ll}-nj}^{Wh}$</a> <li><a href="?table=AuxFig%2011e%20Acc:%20Onshell%20SR$_{DFOS}^{Wh}$">AuxFig 11e Acc: Onshell SR$_{DFOS}^{Wh}$</a> <li><a href="?table=AuxFig%2011f%20Eff:%20Onshell%20SR$_{DFOS}^{Wh}$">AuxFig 11f Eff: Onshell SR$_{DFOS}^{Wh}$</a> <li><a href="?table=AuxFig%2012a%20Acc:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 12a Acc: Off. Wino-bino(+) SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2012b%20Eff:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 12b Eff: Off. Wino-bino(+) SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2012c%20Acc:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 12c Acc: Off. Wino-bino(+) SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2012d%20Eff:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 12d Eff: Off. Wino-bino(+) SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2012e%20Acc:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 12e Acc: Off. Wino-bino(+) SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2012f%20Eff:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 12f Eff: Off. Wino-bino(+) SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2012g%20Acc:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 12g Acc: Off. Wino-bino(+) SR$^{offWZ}_{highETmiss}$-nj</a> <li><a href="?table=AuxFig%2012h%20Eff:%20Off.%20Wino-bino(%2b)%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 12h Eff: Off. Wino-bino(+) SR$^{offWZ}_{highETmiss}$-nj</a> <li><a href="?table=AuxFig%2013a%20Acc:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 13a Acc: Off. Wino-bino(-) SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2013b%20Eff:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 13b Eff: Off. Wino-bino(-) SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2013c%20Acc:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 13c Acc: Off. Wino-bino(-) SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2013d%20Eff:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 13d Eff: Off. Wino-bino(-) SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2013e%20Acc:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 13e Acc: Off. Wino-bino(-) SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2013f%20Eff:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 13f Eff: Off. Wino-bino(-) SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2013g%20Acc:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 13g Acc: Off. Wino-bino(-) SR$^{offWZ}_{highETmiss}$-nj</a> <li><a href="?table=AuxFig%2013h%20Eff:%20Off.%20Wino-bino(-)%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 13h Eff: Off. Wino-bino(-) SR$^{offWZ}_{highETmiss}$-nj</a> <li><a href="?table=AuxFig%2014a%20Acc:%20Off.%20Higgsino%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 14a Acc: Off. Higgsino SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2014b%20Eff:%20Off.%20Higgsino%20SR$^{offWZ}_{lowETmiss}$-0j">AuxFig 14b Eff: Off. Higgsino SR$^{offWZ}_{lowETmiss}$-0j</a> <li><a href="?table=AuxFig%2014c%20Acc:%20Off.%20Higgsino%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 14c Acc: Off. Higgsino SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2014d%20Eff:%20Off.%20Higgsino%20SR$^{offWZ}_{lowETmiss}$-nj">AuxFig 14d Eff: Off. Higgsino SR$^{offWZ}_{lowETmiss}$-nj</a> <li><a href="?table=AuxFig%2014e%20Acc:%20Off.%20Higgsino%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 14e Acc: Off. Higgsino SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2014f%20Eff:%20Off.%20Higgsino%20SR$^{offWZ}_{highETmiss}$-0j">AuxFig 14f Eff: Off. Higgsino SR$^{offWZ}_{highETmiss}$-0j</a> <li><a href="?table=AuxFig%2014g%20Acc:%20Off.%20Higgsino%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 14g Acc: Off. Higgsino SR$^{offWZ}_{highETmiss}$-nj</a> <li><a href="?table=AuxFig%2014h%20Eff:%20Off.%20Higgsino%20SR$^{offWZ}_{highETmiss}$-nj">AuxFig 14h Eff: Off. Higgsino SR$^{offWZ}_{highETmiss}$-nj</a> </ul>

Comparison of the observed data and expected SM background yields in the CRs (pre-fit) and VRs (post-fit) of the onshell $W\!Z$ and $W\!h$ selections. The "Others" category contains the single-top, WW, triboson, Higgs and rare top processes. The hatched band indicates the combined theoretical, experimental, and MC statistical uncertainties. The bottom panel shows the relative difference between the observed data and expected yields for the CRs and the significance of the difference for the VRs, calculated with the profile likelihood method from [169], adding a minus sign if the yield is below the prediction.

Comparison of the observed data and expected SM background yields in the CRs and VRs of the offshell $W\!Z$ selection. The SM prediction is taken from the background-only fit. The "Others" category contains the single-top, WW, triboson, Higgs and rare top processes. The hatched band indicates the combined theoretical, experimental, and MC statistical uncertainties. The bottom panel shows the significance of the difference between the observed and expected yields, calculated with the profile likelihood method from [169], adding a minus sign if the yield is below the prediction.

More…

Direct observation of the dead-cone effect in QCD

The ALICE collaboration Acharya, S. ; Acharya, S. ; Adamova, D. ; et al.
Nature 605 (2022) 440-446, 2022.
Inspire Record 1867966 DOI 10.17182/hepdata.130725

In particle collider experiments, elementary particle interactions with large momentum transfer produce quarks and gluons (known as partons) whose evolution is governed by the strong force, as described by the theory of quantum chromodynamics (QCD). These partons subsequently emit further partons in a process that can be described as a parton shower which culminates in the formation of detectable hadrons. Studying the pattern of the parton shower is one of the key experimental tools for testing QCD. This pattern is expected to depend on the mass of the initiating parton, through a phenomenon known as the dead-cone effect, which predicts a suppression of the gluon spectrum emitted by a heavy quark of mass $m_{\rm{Q}}$ and energy $E$, within a cone of angular size $m_{\rm{Q}}$/$E$ around the emitter. Previously, a direct observation of the dead-cone effect in QCD had not been possible, owing to the challenge of reconstructing the cascading quarks and gluons from the experimentally accessible hadrons. We report the direct observation of the QCD dead cone by using new iterative declustering techniques to reconstruct the parton shower of charm quarks. This result confirms a fundamental feature of QCD. Furthermore, the measurement of a dead-cone angle constitutes a direct experimental observation of the non-zero mass of the charm quark, which is a fundamental constant in the standard model of particle physics.

1 data table

The $R(\theta)$ variable for charm/inclusive emissions in three bins of $E_{Rad}$: 5-10, 10-20 and 20-35 GeV.