利用北京正负电子对撞机(BESII)探测器收集的$5.8 \times 10^7$ $\jpsi$和$1.4 \times 10^7$ $\psip$事例,首次观测到$\jpsi$和$\psip$衰变为${n}{K^0_S}\barΛ+c.c.$,并检验了微扰QCD "12%“规则.在$\jpsi \to {n}{K^0_S}\barΛ+c.c.$的$n\barΛ$阈值附近没有观察到明显的增强,并确定了$\jpsi \to {K^0_S} X, X \to n \bar Λ$的分支比上限。
英文摘要:
The decays of $\jpsi$ and $\psip$ to ${n}{K^0_S}\barΛ+c.c.$ are observed and measured for the first time, and the perturbative QCD ``12%'' rule is tested, based on $5.8 \times 10^7$ $\jpsi$ and $1.4 \times 10^7$ $\psip$ events collected with BESII detector at the Beijing Electron-Positron Collider. No obvious enhancement near $n\barΛ$ threshold in $\jpsi \to {n}{K^0_S}\barΛ+c.c.$ is observed, and the upper limit on the branching ratio of $\jpsi \to {K^0_S} X, X \to n \bar Λ$ is determined.
Search for new resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $\ell^+ \ell^- b\bar b$, $\ell νb\bar b$, and $ν\barν b\bar b$ channels with $pp$ collisions at $\sqrt s = 13$ TeV with the ATLAS detector
Search for resonant production of $t\bar{t}$ decaying to jets in $p\bar p$ collisions at $\sqrt{s}=1.96$ TeV
这封信报告了对非标准模型顶夸克共振$Z'$的搜索,在95%的置信水平下,衰变到$t\bar{t} \rightarrow W^+b W^-\bar{b}$ % \rightarrow qq 'b qq' \bar{b} $, where both $ W $ decay to quarks. We examine the top-antitop quark invariant mass spectrum for the presence of narrow resonant states. The search uses a data sample of $ \ppb $ collisions at a center of mass energy of 1.96 TeV collected by the CDF II detector at the Fermilab Tevatron, with an integrated luminosity of 2.8 fb$ ^{-1} $. No evidence for top-antitop quark resonant production is found. We place upper limits on the production cross section times branching ratio for a speci…
Search for heavy resonances decaying to a $W$ or $Z$ boson and a Higgs boson in the $q\bar{q}^{(\prime)}b\bar{b}$ final state in $pp$ collisions at $\sqrt{s} = 13$ TeV with the ATLAS detector
Search for the Standard Model Higgs boson decaying into $b\bar{b}$ produced in association with top quarks decaying hadronically in $pp$ collisions at $\sqrt{s}$=8 TeV with the ATLAS detector
Several extensions of the Standard Model predict associated production of dark-matter particles with a Higgs boson. Such processes are searched for in final states with missing transverse momentum and a Higgs boson decaying to a $b\bar b$ pair with the ATLAS detector using 36.1 fb$^{-1}$ of $pp$ collisions at a center-of-mass energy of 13 TeV at the LHC. The observed data are in agreement with the Standard Model predictions and limits are placed on the associated production of dark-matter particles and a Higgs boson.
Search for a new resonance decaying to a $W$ or $Z$ boson and a Higgs boson in the $\ell \ell/ \ell ν/ νν+ b \bar{b}$ final states with the ATLAS Detector
A search is presented for heavy bosons decaying to Z($ν\barν$)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…
Search for Charmonium(-like) states decaying into the $Ω^-\barΩ^+$ final states
School of Physical Science and Technology, Lanzhou University(兰州大学物理科学与技术学院);Frontiers Science Center for Rare Isotopes, Lanzhou University(兰州大学稀有同位素前沿科学中心)
Results are reported from a search for new physics in 13 TeV proton-proton collisions in the final state with large missing transverse momentum and two Higgs bosons decaying via H to bb-bar. The search uses a data sample accumulated by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 inverse femtobarns. The search is motivated by models based on gauge-mediated supersymmetry breaking, which predict the electroweak production of a pair of higgsinos, each of which can decay via a cascade process to a Higgs boson and an undetected lightest supersymmetric par…
Search for a CP-odd Higgs boson decaying into a heavy CP-even Higgs boson and a $Z$ boson in the $\ell^+\ell^- t\bar{t}$ and $ν\barνb\bar{b}$ final states using 140 fb$^{-1}$ of data collected with the ATLAS detector
Search for the standard model Higgs boson decaying to a $b\bar{b}$ pair in events with no charged leptons and large missing transverse energy using the full CDF data set
A search for new heavy resonances decaying to a pair of Higgs bosons (HH) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented. Data were collected with the CMS detector at the LHC in 2016-2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. Resonances with a mass between 0.8 and 4.5 TeV are considered using events in which one Higgs boson decays into a bottom quark pair and the other into final states with either one or two charged leptons. Specifically, the single-lepton decay channel HH $\to$ $\mathrm{b\bar{b}}$WW$^*$ $\to$ $\mathrm{b\bar{b}}\ellνq\bar{…
The $Ξ^-_\mathrm{b} π^+ π^-$ invariant mass spectrum is investigated with an event sample of proton-proton collisions at $\sqrt{s} = $ 13 TeV, collected by the CMS experiment at the LHC in 2016-2018 and corresponding to an integrated luminosity of 140 fb$^{-1}$. The ground state $Ξ^-_\mathrm{b}$ is reconstructed via its decays to J$/ψ$ $Ξ^-$ and J$/ψ$ $Ξ^-$ $Λ$ K$^-$. A narrow resonance, labeled $Ξ_\mathrm{b}$(6100)$^-$, is observed at a $Ξ^-_\mathrm{b} π^+ π^-$ invariant mass of 6100.3 $\pm$ 0.2 (stat) $\pm$ 0.1 (syst) $\pm$ 0.6 ($Ξ^-_\mathrm{b}$) MeV, where the last uncertainty reflects the …
A search for the Standard Model Higgs boson produced in association with a top-quark pair, $t\bar{t}H$, is presented. The analysis uses 36.1 fb$^{-1}$ of $pp$ collision data at $\sqrt{s}$ = 13 TeV, collected with the ATLAS detector at the Large Hadron Collider in 2015 and 2016. The search targets the $H \to b\bar{b}$ decay mode. The selected events contain either one or two electrons or muons from the top-quark decays, and are then categorized according to the number of jets and how likely these are to contain $b$-hadrons. Multivariate techniques are used to discriminate between signal and bac…
A search for heavy resonances decaying into a pair of $Z$ bosons leading to $\ell^+\ell^-\ell'^+\ell'^-$ and $\ell^+\ell^-ν\barν$ final states, where $\ell$ stands for either an electron or a muon, is presented. The search uses proton-proton collision data at a centre-of-mass energy of 13 TeV collected from 2015 to 2018 that corresponds to the full integrated luminosity of 139 fb$^{-1}$ recorded by the ATLAS detector during Run 2 of the Large Hadron Collider. Different mass ranges spanning 200 GeV to 2000 GeV for the hypothetical resonances are considered, depending on the final state and mode…
Search for the Standard Model Higgs boson produced in association with top quarks and decaying into $b\bar{b}$ in pp collisions at $\sqrt{s}$ = 8 TeV with the ATLAS detector
A search for heavy resonances decaying into a Higgs boson ($H$) and a new particle ($X$) is reported, utilizing 36.1 fb$^{-1}$ of proton-proton collision data at $\sqrt{s} =$ 13 TeV collected during 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. The particle $X$ is assumed to decay to a pair of light quarks, and the fully hadronic final state $XH \rightarrow q\bar q'b\bar b$ is analysed. The search considers the regime of high $XH$ resonance masses, where the $X$ and $H$ bosons are both highly Lorentz-boosted and are each reconstructed using a single jet with large ra…
Search for decays of the Higgs boson into a pair of pseudoscalar particles decaying into $b\bar{b}τ^+τ^-$ using $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
Measurements are made of differential cross-sections of highly boosted pair-produced top quarks as a function of top-quark and $t\bar{t}$ system kinematic observables using proton--proton collisions at a center-of-mass energy of $\sqrt{s} = 13$ TeV. The data set corresponds to an integrated luminosity of $36.1$ fb$^{-1}$, recorded in 2015 and 2016 with the ATLAS detector at the CERN Large Hadron Collider. Events with two large-radius jets in the final state, one with transverse momentum $p_{\rm T} > 500$ GeV and a second with $p_{\rm T}>350$ GeV, are used for the measurement. The top-quark can…
This paper presents the prospects of measuring $σ(e^{+}e^{-}\to ZH)\times Br(H \to γγ)$ in 3 $Z$ decay channels $Z \to q\bar{q} / μ^{+} μ^{-} / ν\barν$ using the baseline detector with $\sqrt{s} = 240 GeV$ at the Circular Electron Positron Collider (CEPC) . The simulated Monte Carlo events are generated and scaled to an integrated luminosity of 5.6 $ab^{-1}$ to mimic the data. Extrapolated results to 20 $ab^{-1}$ are also shown. The expected statistical precision of this measurement after combining 3 channels of $Z$ boson decay is 7.7\%. With some preliminary estimation on the systematical unc…
Search for heavy resonances decaying into two Higgs bosons in the $\mathrm{b\bar{b}}τ^+τ^-$ final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV
EUROPEAN ORGANIZATION FOR NUCLEAR RESEARCH (CERN)(欧洲核子研究组织(CERN))
Search for leptoquark pair production decaying into $te^- \bar{t}e^+$ or $tμ^- \bar{t}μ^+$ in multi-lepton final states in $pp$ collisions at 13 TeV with the ATLAS detector