A search for cascade decays of charged sleptons and sneutrinos using final states characterized by three leptons (electrons or muons) and missing transverse momentum is presented. The analysis is based on a dataset with 140 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of $\sqrt{s}$=13 TeV recorded by the ATLAS detector at the Large Hadron Collider. This paper focuses on a supersymmetric scenario that is motivated by the muon anomalous magnetic moment observation, dark mattter relic density abundance, and electroweak naturalness. A mass spectrum involving light higgsinos and heavier sleptons with a bino at intermediate mass is targeted. No significant deviation from the Standard Model expectation is observed. This search enables to place stringent constraints on this model, excluding at the 95% confidence level charged slepton and sneutrino masses up to 450 GeV when assuming a lightest neutralino mass of 100 GeV and mass-degenerate selectrons, smuons and sneutrinos.
Distribution of $m_{3\ell}$ in SROS-on-$eee$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.
Distribution of $m_{3\ell}$ in SROS-on-$e\mu\mu$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.
Distribution of $E_{\text{T}}^{\text{miss}}$ in SROS-on-b-$eee$. The SR selections are applied for each distribution, except for the variable shown, for which the selection is indicated by a black arrow. The last bin includes the overflow. The `Others' category contains the production of Higgs boson, 3-top, 4-top, and single-top processes. Distributions for SBH signals are overlaid. The bottom panels show the ratio of the observed data to the predicted total background yields. The hatched band includes all statistical and systematic uncertainties.
A search for exotic decays of the 125 GeV Higgs boson into a pair of new spin-0 particles, $H \to aa$, where one decays into a photon pair and the other into a $\tau$-lepton pair, is presented. Hadronic decays of the $\tau$-leptons are considered and reconstructed using a dedicated tagger for collimated $\tau$-lepton pairs. The search uses 140 fb$^{-1}$ of proton-proton collision data at a centre-of-mass energy of $\sqrt{s}=13$ TeV recorded between 2015 and 2018 by the ATLAS experiment at the Large Hadron Collider. The search is performed in the mass range of the $a$ boson between 10 GeV and 60 GeV. No significant excess of events is observed above the Standard Model background expectation. Model-independent upper limits at 95$\% $ confidence level are set on the branching ratio of the Higgs boson to the $\gamma\gamma\tau\tau$ final state, $\mathcal{B}(H\to aa\to \gamma\gamma\tau\tau)$, ranging from 0.2$\% $ to 2$\% $, depending on the $a$-boson mass hypothesis.
Distribution of the diphoton invariant mass for all events satisfying the analysis selections in the full Run 2 dataset.
Scan of the observed $p$-value as a function of $m_{a}$ for the background-only hypothesis.
The observed and expected ($\pm1\sigma$) upper limits at 95% CL on the branching ratio for $H\rightarrow aa\rightarrow \gamma\gamma\tau\tau$ as a function of the resonance mass hypothesis $m_{a}$.
This article presents a search for a heavy charged Higgs boson produced in association with a top quark and a bottom quark, and decaying into a $W$ boson and a $125$ GeV Higgs boson $h$. The search is performed in final states with one charged lepton, missing transverse momentum, and jets using proton-proton collision data at $\sqrt{s} = 13$ TeV recorded with the ATLAS detector during Run 2 of the LHC at CERN. This data set corresponds to a total integrated luminosity of 140 fb$^{-1}$. The search is conducted by examining the reconstructed invariant mass distribution of the $Wh$ candidates for evidence of a localised excess in the charged Higgs boson mass range from $250$ GeV to $3$ TeV. No significant excess is observed and 95% confidence-level upper limits between $2.8$ pb and $1.2$ fb are placed on the production cross-section times branching ratio for charged Higgs bosons decaying into $Wh$.
Upper limit at the 95% CL on the product of the cross-section for the $pp \rightarrow tb H^{\pm}$ process and the branching ratio $B(W^{\pm} \times B (h \rightarrow b \bar{b} ))$ from the combined fit to all signal and control regions of the resolved analysis.
Upper limit at the 95% CL on the product of the cross-section for the $pp \rightarrow tb H^{\pm}$ process and the branching ratio $B(W^{\pm} \times B (h \rightarrow b \bar{b} ))$ from the combined fit to all signal and control regions of the merged analysis.
Product of acceptance and efficiency for pp->tbH(->Wh) as function of the charged Higgs boson mass for the resolved qqbb low-purity signal region.
This paper presents a search for supersymmetric particles in models with highly compressed mass spectra, in events consistent with being produced through vector boson fusion. The search uses 140 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}=13$ TeV collected by the ATLAS experiment at the Large Hadron Collider. Events containing at least two jets with a large gap in pseudorapidity, large missing transverse momentum, and no reconstructed leptons are selected. A boosted decision tree is used to separate events consistent with the production of supersymmetric particles from those due to Standard Model backgrounds. The data are found to be consistent with Standard Model predictions. The results are interpreted using simplified models of $R$-parity-conserving supersymmetry in which the lightest supersymmetric partner is a bino-like neutralino with a mass similar to that of the lightest chargino and second-to-lightest neutralino, both of which are wino-like. Lower limits at 95% confidence level on the masses of next-to-lightest supersymmetric partners in this simplified model are established between 117 and 120 GeV when the lightest supersymmetric partners are within 1 GeV in mass.
Observed and predicted background distributions of the BDT score in $\text{SR}_\text{2j}$ after the exclusion fit. The nominal, pre-fit prediction of an example benchmark signal with $(m(\widetilde{\chi}_{2}^{0}/\widetilde{\chi}_{1}^{\pm}), \widetilde{\chi}_{1}^{0}) = (100, 99)$ GeV is shown in red. The 'Other' category contains rare backgrounds from diboson, triboson and top-quark production processes. The hatched band represents the post-fit experimental, theoretical, and statistical uncertainties in the total background. The bottom panel of each plot shows the ratio between the data and the post-fit background prediction.
Observed and predicted background distributions of the BDT score in $\text{SR}_{\geq3\text{j}}$ after the exclusion fit. The nominal, pre-fit prediction of an example benchmark signal with $(m(\widetilde{\chi}_{2}^{0}/\widetilde{\chi}_{1}^{\pm}), \widetilde{\chi}_{1}^{0}) = (100, 99)$ GeV is shown in red. The 'Other' category contains rare backgrounds from diboson, triboson and top-quark production processes. The hatched band represents the post-fit experimental, theoretical, and statistical uncertainties in the total background. The bottom panel of each plot shows the ratio between the data and the post-fit background prediction.
Expected (dashed black line) and observed (solid red line) 95% CL exclusion limits on the compressed SUSY simplified model with a bino-like LSP and wino-like NLSPs being considered. These are shown with $\pm1\sigma_\text{exp}$ (yellow band) from experimental systematic and statistical uncertainties, and with $\pm1\sigma^{\text{SUSY}}_{\text{theory}}$ (red dotted lines) from signal cross-section uncertainties, respectively. The limits set by the ATLAS searches using the soft lepton signature is illustrated by the blue region while the limit imposed by the LEP experiments is shown in grey.
A search for a light charged Higgs boson produced in decays of the top quark, $t \to H^\pm b$ with $H^\pm \to cs$, is presented. This search targets the production of top-quark pairs $t\bar{t} \to Wb H^\pm b$, with $W \to \ell\nu$ ($\ell = e, \mu$), resulting in a lepton-plus-jets final state characterised by an isolated electron or muon and at least four jets. The search exploits $b$-quark and $c$-quark identification techniques as well as multivariate methods to suppress the dominant $t\bar{t}$ background. The data analysed correspond to 140 $\text{fb}^{-1}$ of $pp$ collisions at $\sqrt{s} = 13$ TeV recorded with the ATLAS detector at the LHC between 2015 and 2018. Observed (expected) 95% confidence-level upper limits on the branching fraction $\mathscr{B}(t\to H^\pm b)$, assuming $\mathscr{B}(t\to Wb) + \mathscr{B}(t \to H^\pm (\to cs)b)=1.0$, are set between 0.066% (0.077%) and 3.6% (2.3%) for a charged Higgs boson with a mass between 60 GeV and 168 GeV.
Distributions of the dijet mass. The processes $t\bar{t}$(allHad), $tW$, Single top, $t\bar{t}H$, Other top, $W$ + jets, $Z$ + jets, and $VV$ listed are combined with the multijet background in the ‘Other’ category. The uncertainty band represents the combined statistical and systematic uncertainty of the prediction. Overlaid are the shapes for the $H^{\pm}_{80}$ and $H^{\pm}_{150}$ signal samples normalised to the total background prediction.
Data and background yields after the background-only fit of the BDT-score distribution for the $130\,$GeV signal mass BDT training. For comparison, the expected signal yield for $\mathscr{B}_{H^{\pm}}=1.0\%$ is added.
Observed (solid line) and expected (dotted line) upper limits on $\mathscr{B}_{H^{\pm}}$ for charged Higgs boson with masses between $60\,$GeV and $168\,$GeV, assuming $\mathscr{B}(t \to H^{\pm}(\to cs) b) = 1.0$. The $\pm 1 \sigma$ and $\pm 2 \sigma$ variations around the expected upper limit are indicated by the green and yellow bands, respectively.
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.
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.
We report on measurements of dielectron ($e^+e^-$) production in Au$+$Au collisions at a center-of-mass energy of 200 GeV per nucleon-nucleon pair using the STAR detector at RHIC. Systematic measurements of the dielectron yield as a function of transverse momentum ($p_{\rm T}$) and collision centrality show an enhancement compared to a cocktail simulation of hadronic sources in the low invariant-mass region ($M_{ee}<$ 1 GeV/$c^2$). This enhancement cannot be reproduced by the $\rho$-meson vacuum spectral function. In minimum-bias collisions, in the invariant-mass range of 0.30 $-$ 0.76 GeV/$c^2$, integrated over the full $p_{\rm T}$ acceptance, the enhancement factor is 1.76 $\pm$ 0.06 (stat.) $\pm$ 0.26 (sys.) $\pm$ 0.29 (cocktail). The enhancement factor exhibits weak centrality and $p_{\rm T}$ dependence in STAR's accessible kinematic regions, while the excess yield in this invariant-mass region as a function of the number of participating nucleons follows a power-law shape with a power of 1.44 $\pm$ 0.10. Models that assume an in-medium broadening of the $\rho$ meson spectral function consistently describe the observed excess in these measurements. Additionally, we report on measurements of $\omega$ and $\phi$-meson production through their $e^+e^-$ decay channel. These measurements show good agreement with Tsallis Blast-Wave model predictions as well as, in the case of the $\phi$-meson, results through its $K^+K^-$ decay channel. In the intermediate invariant-mass region (1.1$<M_{ee}<$ 3 GeV/$c^2$), we investigate the spectral shapes from different collision centralities. Physics implications for possible in-medium modification of charmed hadron production and other physics sources are discussed.
Estimated electron purity vs. momentum in 200 GeV Au + Au collisions.
Acceptance correction factor for unlike-sign and like-sign pair difference from 200 GeV Au+Au minimum-bias collisions.
Ratio of the same-event like-sign to the mixed event unlike-sign distributions.
Two-particle azimuthal ($\Delta\phi$) and pseudorapidity ($\Delta\eta$) correlations using a trigger particle with large transverse momentum ($p_T$) in $d$+Au, Cu+Cu and Au+Au collisions at $\sqrt{s_{{NN}}}$ =\xspace 62.4 GeV and 200~GeV from the STAR experiment at RHIC are presented. The \ns correlation is separated into a jet-like component, narrow in both $\Delta\phi$ and $\Delta\eta$, and the ridge, narrow in $\Delta\phi$ but broad in $\Delta\eta$. Both components are studied as a function of collision centrality, and the jet-like correlation is studied as a function of the trigger and associated $p_T$. The behavior of the jet-like component is remarkably consistent for different collision systems, suggesting it is produced by fragmentation. The width of the jet-like correlation is found to increase with the system size. The ridge, previously observed in Au+Au collisions at $\sqrt{s_{{NN}}}$ = 200 GeV, is also found in Cu+Cu collisions and in collisions at $\sqrt{s_{{NN}}}$ =\xspace 62.4 GeV, but is found to be substantially smaller at $\sqrt{s_{{NN}}}$ =\xspace 62.4 GeV than at $\sqrt{s_{{NN}}}$ = 200 GeV for the same average number of participants ($ \langle N_{\mathrm{part}}\rangle$). Measurements of the ridge are compared to models.
Parameterizations of the transverse momentum dependence of the reconstruction efficiency of charged particles in the TPC in various collision systems, energies and centrality bins for the track selection cuts used in this analysis.
The raw correlation in $\Delta\eta$ for di-hadron correlations for 3 $<$ $p_T^{trigger}$ $<$ 6 GeV/$c$ and 1.5 GeV/$c$ $<$ $p_T^{associated}$ $<$ $p_T^{trigger}$ for 0-12% central \Au collisions for $|\Delta\phi|<$ 0.78 before and after the track merging correction is applied. The data have been reflected about $\Delta\eta$=0.
Sample correlations in $\Delta\eta$ ($|\Delta\phi|<$ 0.78) for 3 $<$ $p_T^{trigger}$ $<$ 6 GeV/$c$ and 1.5 GeV/$c$ $<$ $p_T^{associated}$ $<$ $p_T^{trigger}$ for 0-60% Cu+Cu at $\sqrt{s_{NN}}$ = 62.4 GeV, 0-80% Au+Au at $\sqrt{s_{NN}}$ = 62.4 GeV, 0-95% $d$+Au at $\sqrt{s_{NN}}$ = 200 GeV, 0-60% Cu+Cu at $\sqrt{s_{NN}}$ = 200 GeV, 40-80% Au+Au at $\sqrt{s_{NN}}$ = 200 GeV, and 0-12% central Au+Au at $\sqrt{s_{NN}}$ = 200 GeV. The data are averaged between positive and negative $\Delta\eta$. 5% systematic uncertainty due to track reconstruction efficiency not listed below.
The results of mid-rapidity ($0 < y < 0.8$) neutral pion spectra over an extended transverse momentum range ($1 < p_T < 12$ GeV/$c$) in $\sqrt{s_{NN}}$ = 200 GeV Au+Au collisions, measured by the STAR experiment, are presented. The neutral pions are reconstructed from photons measured either by the STAR Barrel Electro-Magnetic Calorimeter (BEMC) or by the Time Projection Chamber (TPC) via tracking of conversion electron-positron pairs. Our measurements are compared to previously published $\pi^{\pm}$ and $\pi^0$ results. The nuclear modification factors $R_{\mathrm{CP}}$ and $R_{\mathrm{AA}}$ of $\pi^0$ are also presented as a function of $p_T$ . In the most central Au+Au collisions, the binary collision scaled $\pi^0$ yield at high $p_T$ is suppressed by a factor of about 5 compared to the expectation from the yield of p+p collisions. Such a large suppression is in agreement with previous observations for light quark mesons and is consistent with the scenario that partons suffer considerable energy loss in the dense medium formed in central nucleus-nucleus collisions at RHIC.
The diphoton invariant mass distributions using the EMC-TPC method in 0-20% Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV.
The diphoton invariant mass distributions using the EMC-TPC method in 0-20% Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV.
The diphoton invariant mass distributions using the EMC-EMC method in 0-20% Au+Au collisions at $\sqrt{s_{NN}}=200$ GeV.
We present the multiplicity and pseudorapidity distributions of photons produced in Au+Au and Cu+Cu collisions at \sqrt{s_NN} = 62.4 and 200 GeV. The photons are measured in the region -3.7 < \eta < -2.3 using the photon multiplicity detector in the STAR experiment at RHIC. The number of photons produced per average number of participating nucleon pairs increases with the beam energy and is independent of the collision centrality. For collisions with similar average numbers of participating nucleons the photon multiplicities are observed to be similar for Au+Au and Cu+Cu collisions at a given beam energy. The ratios of the number of charged particles to photons in the measured pseudorapidity range are found to be 1.4 +/- 0.1 and 1.2 +/- 0.1 for \sqrt{s_NN} = 62.4 GeV and 200 GeV, respectively. The energy dependence of this ratio could reflect varying contributions from baryons to charged particles, while mesons are the dominant contributors to photon production in the given kinematic region. The photon pseudorapidity distributions normalized by average number of participating nucleon pairs, when plotted as a function of \eta - ybeam, are found to follow a longitudinal scaling independent of centrality and colliding ion species at both beam energies.
Fig. 1. (Color online.) Top panel: Photon reconstruction efficiency $\left(\epsilon_{\gamma}\right)$ (solid symbols) and purity of photon sample $\left(f_{\mathrm{p}}\right)$ (open symbols) for PMD as a function of pseudorapidity $(\eta)$ for minimum bias $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=$ $200 \mathrm{GeV}$. Bottom panel: Comparison between estimated $\epsilon_{\gamma}$ and $f_{\mathrm{p}}$ for PMD as a function of $\eta$ for minimum bias $\mathrm{Au}+\mathrm{Au}$ at $\sqrt{s_{\mathrm{NN}}}=62.4 \mathrm{GeV}$ using HIJING and AMPT models. The error bars on the AMPT data are statistical and those for HIJING are within the symbol size. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.
Fig. 1. (Color online.) Top panel: Photon reconstruction efficiency $\left(\epsilon_{\gamma}\right)$ (solid symbols) and purity of photon sample $\left(f_{\mathrm{p}}\right)$ (open symbols) for PMD as a function of pseudorapidity $(\eta)$ for minimum bias $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=$ $200 \mathrm{GeV}$. Bottom panel: Comparison between estimated $\epsilon_{\gamma}$ and $f_{\mathrm{p}}$ for PMD as a function of $\eta$ for minimum bias $\mathrm{Au}+\mathrm{Au}$ at $\sqrt{s_{\mathrm{NN}}}=62.4 \mathrm{GeV}$ using HIJING and AMPT models. The error bars on the AMPT data are statistical and those for HIJING are within the symbol size. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.
Fig. 2. (Color online.) Event-by-event photon multiplicity distributions (solid circles) for $\mathrm{Au}+\mathrm{Au}$ and $\mathrm{Cu}+\mathrm{Cu}$ at $\sqrt{s_{\mathrm{NN}}}=62.4$ and $200 \mathrm{GeV} .$ The distributions for top $0-5 \%$ central $\mathrm{Au}+$ Au collisions and top $0-10 \%$ central $\mathrm{Cu}+\mathrm{Cu}$ collisions are also shown (open circles). The photon multiplicity distributions for central collisions are observed to be Gaussian (solid line). Only statistical errors are shown. NOTE: For points with invisible error bars, the point size was considered as an absolute upper limit for the uncertainty.