Bound states of charm and anticharm quarks, known as charmonia, have a rich spectroscopic structure that can be used to probe the dynamics of hadron production in high-energy hadron collisions. Here, the cross section ratio of excited ($ψ$(2S)) and ground state (J/$ψ$) vector mesons is measured as a function of the charged-particle multiplicity in proton-lead (pPb) collisions at a center-of-mass (CM) energy per nucleon pair of 8.16 TeV. The data corresponding to an integrated luminosity of 175 nb$^{-1}$ were collected using the CMS detector. The ratio is measured separately for prompt and nonprompt charmonia in the transverse momentum range 6.5 $\lt$$p_\text{T}$$\lt$ 30 GeV and in four rapidity ranges spanning $-$2.865 $\lt$$y_\text{CM}$$\lt$ 1.935. For the first time, a statistically significant multiplicity dependence of the prompt cross section ratio is observed in proton-nucleus collisions. There is no clear rapidity dependence in the ratio. The prompt measurements are compared with a theoretical model which includes interactions with nearby particles during the evolution of the system. These results provide additional constraints on hadronization models of heavy quarks in nuclear collisions.
Normalized $\sigma_{\psi(2S)}/\sigma_{J/\psi}$ in $6.5<p_T<30.0\,GeV$ and $ -2.865 < y_{CM} < -2$ as functions of normalized $\text{N}^{{\text{corr.}}}_{\text{track}}$
Normalized $\sigma_{\psi(2S)}/\sigma_{J/\psi}$ in $6.5<p_T<30.0\,GeV$ and $ -2 < y_{CM} < -1$ as functions of normalized $\text{N}^{{\text{corr.}}}_{\text{track}}$
Normalized $\sigma_{\psi(2S)}/\sigma_{J/\psi}$ in $6.5<p_T<30.0\,GeV$ and $ -1 < y_{CM} < 1$ as functions of normalized $\text{N}^{{\text{corr.}}}_{\text{track}}$
A search for long-lived particles decaying into hadrons is presented. The analysis uses 139 fb$^{-1}$ of $pp$ collision data collected at $\sqrt{s} = 13$ TeV by the ATLAS detector at the LHC using events that contain multiple energetic jets and a displaced vertex. The search employs dedicated reconstruction techniques that significantly increase the sensitivity to long-lived particles decaying in the ATLAS inner detector. Background estimates for Standard Model processes and instrumental effects are extracted from data. The observed event yields are compatible with those expected from background processes. The results are used to set limits at 95% confidence level on model-independent cross sections for processes beyond the Standard Model, and on scenarios with pair-production of supersymmetric particles with long-lived electroweakinos that decay via a small $R$-parity-violating coupling. The pair-production of electroweakinos with masses below 1.5 TeV is excluded for mean proper lifetimes in the range from 0.03 ns to 1 ns. When produced in the decay of $m(\tilde{g})=2.4$ TeV gluinos, electroweakinos with $m(\tilde\chi^0_1)=1.5$ TeV are excluded with lifetimes in the range of 0.02 ns to 4 ns.
<b>Tables of Yields:</b> <a href="?table=validation_regions_yields_highpt_SR">Validation Regions Summary Yields, High-pT jet selections</a> <a href="?table=validation_regions_yields_trackless_SR">Validiation Regions Summary Yields, Trackless jet selections</a> <a href="?table=yields_highpt_SR_observed">Signal region (and sidebands) observed yields, High-pT jet selections</a> <a href="?table=yields_highpt_SR_expected">Signal region (and sidebands) expected yields, High-pT jet selections</a> <a href="?table=yields_trackless_SR_observed">Signal region (and sidebands) observed yields, Trackless jet selections</a> <a href="?table=yields_trackless_SR_expected">Signal region (and sidebands) expected yields, Trackless jet selections</a> <b>Exclusion Contours:</b> <a href="?table=excl_ewk_exp_nominal">EWK RPV signal; expected, nominal</a> <a href="?table=excl_ewk_exp_up">EWK RPV signal; expected, $+1\sigma$</a> <a href="?table=excl_ewk_exp_down">EWK RPV signal; expected, $-1\sigma$</a> <a href="?table=excl_ewk_obs_nominal">EWK RPV signal; observed, nominal</a> <a href="?table=excl_ewk_obs_up">EWK RPV signal; observed, $+1\sigma$</a> <a href="?table=excl_ewk_obs_down">EWK RPV signal; observed, $-1\sigma$</a> <a href="?table=excl_strong_mgluino_2400_GeV_exp_nominal">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; expected, nominal</a> <a href="?table=excl_strong_mgluino_2400_GeV_exp_up">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; expected, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2400_GeV_exp_down">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; expected, $-1\sigma$</a> <a href="?table=excl_strong_mgluino_2400_GeV_obs_nominal">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; observed, nominal</a> <a href="?table=excl_strong_mgluino_2400_GeV_obs_up">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; observed, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2400_GeV_obs_down">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; observed, $-1\sigma$</a> <a href="?table=excl_xsec_ewk">EWK RPV signal; cross-section limits for fixed lifetime values.</a> <a href="?table=excl_xsec_strong_mgluino_2400">Strong RPV signal, m($\tilde{g}$)=2.4 TeV; cross-section limits for fixed lifetime values.</a> <a href="?table=excl_strong_mgluino_2000_GeV_exp_nominal">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; expected, nominal</a> <a href="?table=excl_strong_mgluino_2000_GeV_exp_up">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; expected, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2000_GeV_exp_down">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; expected, $-1\sigma$</a> <a href="?table=excl_strong_mgluino_2000_GeV_obs_nominal">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; observed, nominal</a> <a href="?table=excl_strong_mgluino_2000_GeV_obs_up">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; observed, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2000_GeV_obs_down">Strong RPV signal, m($\tilde{g}$)=2.0 TeV; observed, $-1\sigma$</a> <a href="?table=excl_strong_mgluino_2200_GeV_exp_nominal">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; expected, nominal</a> <a href="?table=excl_strong_mgluino_2200_GeV_exp_up">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; expected, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2200_GeV_exp_down">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; expected, $-1\sigma$</a> <a href="?table=excl_strong_mgluino_2200_GeV_obs_nominal">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; observed, nominal</a> <a href="?table=excl_strong_mgluino_2200_GeV_obs_up">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; observed, $+1\sigma$</a> <a href="?table=excl_strong_mgluino_2200_GeV_obs_down">Strong RPV signal, m($\tilde{g}$)=2.2 TeV; observed, $-1\sigma$</a> <a href="?table=excl_strong_mchi0_50_GeV_exp_nominal">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; expected, nominal</a> <a href="?table=excl_strong_mchi0_50_GeV_exp_up">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; expected, $+1\sigma$</a> <a href="?table=excl_strong_mchi0_50_GeV_exp_down">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; expected, $-1\sigma$</a> <a href="?table=excl_strong_mchi0_50_GeV_obs_nominal">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; observed, nominal</a> <a href="?table=excl_strong_mchi0_50_GeV_obs_up">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; observed, $+1\sigma$</a> <a href="?table=excl_strong_mchi0_50_GeV_obs_down">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.1 TeV; observed, $-1\sigma$</a> <a href="?table=excl_strong_mchi0_450_GeV_exp_nominal">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; expected, nominal</a> <a href="?table=excl_strong_mchi0_450_GeV_exp_up">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; expected, $+1\sigma$</a> <a href="?table=excl_strong_mchi0_450_GeV_exp_down">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; expected, $-1\sigma$</a> <a href="?table=excl_strong_mchi0_450_GeV_obs_nominal">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; observed, nominal</a> <a href="?table=excl_strong_mchi0_450_GeV_obs_up">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; observed, $+1\sigma$</a> <a href="?table=excl_strong_mchi0_450_GeV_obs_down">Strong RPV signal, m($\tilde{\chi}^{0}$)=0.5 TeV; observed, $-1\sigma$</a> <a href="?table=excl_strong_tau_0p01_ns_exp_nominal">Strong RPV signal, $\tau$=0.01 ns; expected, nominal</a> <a href="?table=excl_strong_tau_0p01_ns_exp_up">Strong RPV signal, $\tau$=0.01 ns; expected, $+1\sigma$</a> <a href="?table=excl_strong_tau_0p01_ns_exp_down">Strong RPV signal, $\tau$=0.01 ns; expected, $-1\sigma$</a> <a href="?table=excl_strong_tau_0p01_ns_obs_nominal">Strong RPV signal, $\tau$=0.01 ns; observed, nominal</a> <a href="?table=excl_strong_tau_0p01_ns_obs_up">Strong RPV signal, $\tau$=0.01 ns; observed, $+1\sigma$</a> <a href="?table=excl_strong_tau_0p01_ns_obs_down">Strong RPV signal, $\tau$=0.01 ns; observed, $-1\sigma$</a> <a href="?table=excl_strong_tau_0p1_ns_exp_nominal">Strong RPV signal, $\tau$=0.10 ns; expected, nominal</a> <a href="?table=excl_strong_tau_0p1_ns_exp_up">Strong RPV signal, $\tau$=0.10 ns; expected, $+1\sigma$</a> <a href="?table=excl_strong_tau_0p1_ns_exp_down">Strong RPV signal, $\tau$=0.10 ns; expected, $-1\sigma$</a> <a href="?table=excl_strong_tau_0p1_ns_obs_nominal">Strong RPV signal, $\tau$=0.10 ns; observed, nominal</a> <a href="?table=excl_strong_tau_0p1_ns_obs_up">Strong RPV signal, $\tau$=0.10 ns; observed, $+1\sigma$</a> <a href="?table=excl_strong_tau_0p1_ns_obs_down">Strong RPV signal, $\tau$=0.10 ns; observed, $-1\sigma$</a> <a href="?table=excl_strong_tau_1_ns_exp_nominal">Strong RPV signal, $\tau$=1.00 ns; expected, nominal</a> <a href="?table=excl_strong_tau_1_ns_exp_up">Strong RPV signal, $\tau$=1.00 ns; expected, $+1\sigma$</a> <a href="?table=excl_strong_tau_1_ns_exp_down">Strong RPV signal, $\tau$=1.00 ns; expected, $-1\sigma$</a> <a href="?table=excl_strong_tau_1_ns_obs_nominal">Strong RPV signal, $\tau$=1.00 ns; observed, nominal</a> <a href="?table=excl_strong_tau_1_ns_obs_up">Strong RPV signal, $\tau$=1.00 ns; observed, $+1\sigma$</a> <a href="?table=excl_strong_tau_1_ns_obs_down">Strong RPV signal, $\tau$=1.00 ns; observed, $-1\sigma$</a> <a href="?table=excl_strong_tau_10_ns_exp_nominal">Strong RPV signal, $\tau$=10.00 ns; expected, nominal</a> <a href="?table=excl_strong_tau_10_ns_exp_up">Strong RPV signal, $\tau$=10.00 ns; expected, $+1\sigma$</a> <a href="?table=excl_strong_tau_10_ns_exp_down">Strong RPV signal, $\tau$=10.00 ns; expected, $-1\sigma$</a> <a href="?table=excl_strong_tau_10_ns_obs_nominal">Strong RPV signal, $\tau$=10.00 ns; observed, nominal</a> <a href="?table=excl_strong_tau_10_ns_obs_up">Strong RPV signal, $\tau$=10.00 ns; observed, $+1\sigma$</a> <a href="?table=excl_strong_tau_10_ns_obs_down">Strong RPV signal, $\tau$=10.00 ns; observed, $-1\sigma$</a> <a href="?table=excl_xsec_strong_chi0_1250">Strong RPV signal, m($\tilde{\chi}^0_1$)=1.25 TeV; cross-section limits for fixed lifetime values.</a> <br/><b>Reinterpretation Material:</b> See the attached resource (purple button on the left) or directly <a href="https://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/SUSY-2016-08/hepdata_info.pdf">this link</a> for information about acceptance definition and about how to use the efficiency histograms below. SLHA files are also available in the reource page of this HEPData record. <a href="?table=acceptance_highpt_strong"> Acceptance cutflow, High-pT SR, Strong production.</a> <a href="?table=acceptance_trackless_ewk"> Acceptance cutflow, Trackless SR, EWK production.</a> <a href="?table=acceptance_trackless_ewk_hf"> Acceptance cutflow, Trackless SR, EWK production with heavy-flavor.</a> <a href="?table=acceptance_highpt_ewk_hf"> Acceptance cutflow, Trackless SR, EWK production with heavy-flavor.</a> <a href="?table=event_efficiency_HighPt_R_1150_mm">Reinterpretation Material: Event-level Efficiency for HighPt SR selections, R < 1150 mm</a> <a href="?table=event_efficiency_HighPt_R_1150_3870_mm">Reinterpretation Material: Event-level Efficiency for HighPt SR selections, R [1150, 3870] mm</a> <a href="?table=event_efficiency_HighPt_R_3870_mm">Reinterpretation Material: Event-level Efficiency for HighPt SR selections, R > 3870 mm</a> <a href="?table=event_efficiency_Trackless_R_1150_mm">Reinterpretation Material: Event-level Efficiency for Trackless SR selections, R < 1150 mm</a> <a href="?table=event_efficiency_Trackless_R_1150_3870_mm">Reinterpretation Material: Event-level Efficiency for Trackless SR selections, R [1150, 3870] mm</a> <a href="?table=event_efficiency_Trackless_R_3870_mm">Reinterpretation Material: Event-level Efficiency for Trackless SR selections, R > 3870 mm</a> <a href="?table=vertex_efficiency_R_22_mm">Reinterpretation Material: Vertex-level Efficiency for R < 22 mm</a> <a href="?table=vertex_efficiency_R_22_25_mm">Reinterpretation Material: Vertex-level Efficiency for R [22, 25] mm</a> <a href="?table=vertex_efficiency_R_25_29_mm">Reinterpretation Material: Vertex-level Efficiency for R [25, 29] mm</a> <a href="?table=vertex_efficiency_R_29_38_mm">Reinterpretation Material: Vertex-level Efficiency for R [29, 38] mm</a> <a href="?table=vertex_efficiency_R_38_46_mm">Reinterpretation Material: Vertex-level Efficiency for R [38, 46] mm</a> <a href="?table=vertex_efficiency_R_46_73_mm">Reinterpretation Material: Vertex-level Efficiency for R [46, 73] mm</a> <a href="?table=vertex_efficiency_R_73_84_mm">Reinterpretation Material: Vertex-level Efficiency for R [73, 84] mm</a> <a href="?table=vertex_efficiency_R_84_111_mm">Reinterpretation Material: Vertex-level Efficiency for R [84, 111] mm</a> <a href="?table=vertex_efficiency_R_111_120_mm">Reinterpretation Material: Vertex-level Efficiency for R [111, 120] mm</a> <a href="?table=vertex_efficiency_R_120_145_mm">Reinterpretation Material: Vertex-level Efficiency for R [120, 145] mm</a> <a href="?table=vertex_efficiency_R_145_180_mm">Reinterpretation Material: Vertex-level Efficiency for R [145, 180] mm</a> <a href="?table=vertex_efficiency_R_180_300_mm">Reinterpretation Material: Vertex-level Efficiency for R [180, 300] mm</a> <br/><b>Cutflow Tables:</b> <a href="?table=cutflow_highpt_strong"> Cutflow (Acceptance x Efficiency), High-pT SR, Strong production.</a> <a href="?table=cutflow_trackless_ewk"> Cutflow (Acceptance x Efficiency), Trackless SR, EWK production.</a> <a href="?table=cutflow_trackless_ewk_hf"> Cutflow (Acceptance x Efficiency), Trackless SR, EWK production with heavy-flavor quarks.</a> <a href="?table=cutflow_highpt_ewk_hf"> Cutflow (Acceptance x Efficiency), High-pT SR, EWK production with heavy-flavor quarks.</a>
Validation of background estimate in validation regions for the High-pT jet selections
Validation of background estimate in validation regions for the Trackless jet selections
A search for the pair production of the lightest supersymmetric partner of the top quark, the top squark ($\tilde{\mathrm{t}}_1$), is presented. The search targets the four-body decay of the $\tilde{\mathrm{t}}_1$, which is preferred when the mass difference between the top squark and the lightest supersymmetric particle is smaller than the mass of the W boson. This decay mode consists of a bottom quark, two other fermions, and the lightest neutralino ($\tilde{\chi}^0_1$), which is assumed to be the lightest supersymmetric particle. The data correspond to an integrated luminosity of 138 fb$^{-1}$ of proton-proton collisions at a center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC. Events are selected using the presence of a high-momentum jet, an electron or muon with low transverse momentum, and a significant missing transverse momentum. The signal is selected based on a multivariate approach that is optimized for the difference between $m(\tilde{\mathrm{t}}_1)$ and $m(\tilde{\chi}^0_1)$. The contribution from leading background processes is estimated from data. No significant excess is observed above the expectation from standard model processes. The results of this search exclude top squarks at 95% confidence level for masses up to 480 and 700 GeV for $m(\tilde{\mathrm{t}}_1) - m(\tilde{\chi}^0_1$) = 10 and 80 GeV, respectively.
Distribution of $p_{T}(l)$ after the preselection from 2017 data (black points) and simulation (colored lines). The simulated distribution of two signal points are represented by colored lines, while not being stacked on the background distributions: $(m(\mathrm{\widetilde{t}}_{1}),m(\widetilde{\chi}^{0}_{1}))$ = (500, 490) and (500, 420) GeV. The last bin includes the overflow events.
The ratio of data to the sum of the SM backgrounds. The uncertainties of simulated data are only the statistical unvertainty in the simulation predictions.
Distribution of $p_{T}(l)$ after the preselection from 2018 data (black points) and simulation (colored lines). The simulated distribution of two signal points are represented by colored lines, while not being stacked on the background distributions: $(m(\mathrm{\widetilde{t}}_{1}),m(\widetilde{\chi}^{0}_{1}))$ = (500, 490) and (500, 420) GeV. The last bin includes the overflow events.
A search is presented for heavy bosons decaying to Z($\nu\bar{\nu}$)V(qq'), where V can be a W or a Z boson. A sample of proton-proton collision data at $\sqrt{s} =$ 13 TeV was collected by the CMS experiment during 2016-2018. The data correspond to an integrated luminosity of 137 fb$^{-1}$. The event categorization is based on the presence of high-momentum jets in the forward region to identify production through weak vector boson fusion. Additional categorization uses jet substructure techniques and the presence of large missing transverse momentum to identify W and Z bosons decaying to quarks and neutrinos, respectively. The dominant standard model backgrounds are estimated using data taken from control regions. The results are interpreted in terms of radion, W' boson, and graviton models, under the assumption that these bosons are produced via gluon-gluon fusion, Drell-Yan, or weak vector boson fusion processes. No evidence is found for physics beyond the standard model. Upper limits are set at 95% confidence level on various types of hypothetical new bosons. Observed (expected) exclusion limits on the masses of these bosons range from 1.2 to 4.0 (1.1 to 3.7) TeV.
Simulated distributions are shown for the cosine of the decay angle of SM vector bosons in the rest frame of a parent particle with a mass (mX) of 2\TeV. Solid lines represent VBF scenarios. Dashed lines represent ggF/DY scenarios.
Distributions of mT for ggF/DY-produced resonances X of mass 4.5 TeV.
Distributions of mT for VBF-produced resonances X of mass 4.5 TeV.
We have measured gluon splitting into bottom quarks, g→b b ̄ , in hadronic Z 0 decays collected by SLD between 1996 and 1998. The analysis was performed by looking for secondary bottom production in 4-jet events of any primary flavor. 4-jet events were identified, and in each event a topological vertex-mass technique was applied to the two jets closest in angle in order to identify them as b or b ̄ jets. The upgraded CCD-based vertex detector gives very high B -tagging efficiency, especially for B hadrons with the low energies typical of this process. We measured the rate of g→b b ̄ production per hadronic event, g b b ̄ , to be (2.44±0.59(stat.)±0.34(syst.))×10 −3 .
No description provided.
The rates are measured per hadronic Z decay for gluon splitting to bb(bar) quark pairs, g_bb, and of events containing two bb(bar) quark pairs, g_4b, using a sample of four-jet events selected from data collected with the OPAL detector. Events with an enhanced signal of gluon splitting to bb(bar) quarks are selected if two of the jets are close in phase-space and contain detached secondary vertices. For the event sample containing two bb(bar) quark pairs, three of the four jets are required to have a significantly detached secondary vertex. Information from the event topology is combined in a likelihood fit to extract the values of g_bb and g_4b, namely g_bb = (3.07 +- 0.53(stat) +- 0.97(syst))x10^-3 g_4b = (0.36 +- 0.17(stat) +- 0.27(syst))x10^-3
No description provided.
Quark and gluon jets with the same energy, 24 GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on a track impact parameter method. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity, Evidence is presented which shows that the corresponding differences between gluon and b jets are significantly smaller. In a statistically limited comparison the multiplicity in c jets was found to be comparable with that observed for the jets of mixed quark flavour.
B-jets are identified with the lepton-tag analysis.
The same kinematics as in the table 1.
We have measured the multiplicity of charm quark pairs arising from gluon splitting in a sample of about 3.5 million hadronic Z 0 decays. By selecting a 3-jet event topology and tagging charmed hadrons in the lowest energy jet using leptons, we established a signature of heavy quark pair production from gluons. The average number of gluons splitting into a c c pair per hadronic event was measured to be n g→c c =(2.27±0.28±0.41) × 10 −2 .
Axis error includes +- 8.4/8.4 contribution (Total generator error for the electron channel due to the uncertainties in parameters of Peterson model of fragmentation, LAMBDA_QCD, ALPHA_S, Lund fragmentation parameters and lepton decay model).
The production dynamics of baryon-antibaryon pairs are investigated using hadronic Z 0 decays, recorded with the OPAL detector, which contain at least two identified Λ baryons. The rapidly difference for Λ Λ pairs shows the correlations expected from models with a chain-like production of baryon-antibaryon pairs. If the baryon number of a Λ is compensated by a Λ , the Λ is found with a probability of 53% in an interval of ±0.6 around the Λ rapidity. This correlation strength is weaker than predicted by the Herwig Monte Carlo and the Jetset Monte Carlo with a production chain of baryon-antibaryon, and stronger than predicted by the UCLA model. The observed rapidity correlations can be described by the Jetset Monte Carlo with a dominant production chain of baryon-meson-antibaryon, the popcorn mechanism. In addition to the short range correlations, one finds an indication of a correlation of Λ Λ pairs in opposite hemispheres if both the Λ and the Λ have large rapidities. Such long range correlations are expected if the primary quark flavours are compensated in opposite hemispheres and if these quarks are found in energetic baryons. Rates for simultaneous baryon and strangeness number compensation for Λ Λ , Ξ − Ξ + and Ξ − Λ ( Λ + Λ ) are measured and compared with different Monte Carlo models.
No description provided.
Opposite and same baryon number invariant PI P mass distribuition for additional LAMBDA(LAMBDABAR) candidates in events with one identified LAMBDA(LAMBDABAR). CT.= Data read from plot.
Opposite and same baryon number invariant PI P mass distribuition for additional LAMBDA(LAMBDABAR) candidates in events with one identified XI-(XIBAR+). CT.= Data read from plot.