A search for the weak production of charginos and neutralinos decaying to a final state with three leptons (electrons or muons) and missing transverse momentum is presented. The analysis uses 2.06 ...fb(-1) of √s=7 TeV proton-proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with standard model expectations in two signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric and simplified models. For the simplified models, degenerate lightest chargino and next-to-lightest neutralino masses up to 300 GeV are excluded for mass differences from the lightest neutralino up to 300 GeV.
Many low-threshold experiments observe sharply rising event rates of yet unknown origins below a few hundred eV, and larger than expected from known backgrounds. Due to the significant impact of this ...excess on the dark matter or neutrino sensitivity of these experiments, a collective effort has been started to share the knowledge about the individual observations. For this, the EXCESS Workshop was initiated. In its first iteration in June 2021, ten rare event search collaborations contributed to this initiative via talks and discussions. The contributing collaborations were CONNIE, CRESST, DAMIC, EDELWEISS, MINER, NEWS-G, NUCLEUS, RICOCHET, SENSEI and SuperCDMS. They presented data about their observed energy spectra and known backgrounds together with details about the respective measurements. In this paper, we summarize the presented information and give a comprehensive overview of the similarities and differences between the distinct measurements. The provided data is furthermore publicly available on the workshop's data repository together with a plotting tool for visualization.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract A detailed description is reported of the analysis used by the CMS Collaboration in the search for the standard ...model Higgs boson in pp collisions at the LHC, which led to the observation of a new boson. The data sample corresponds to integrated luminosities up to 5.1 fb^sup -1^ at ... TeV, and up to 5.3 fb^sup -1^ at ... TeV. The results for five Higgs boson decay modes γγ, ZZ, WW, ττ, and bb, which show a combined local significance of 5 standard deviations near 125 GeV, are reviewed. A fit to the invariant mass of the two high resolution channels, γγ and ZZ arrow right 4, gives a mass estimate of 125.3 ± 0.4 (stat.) ± 0.5 (syst.) GeV. The measurements are interpreted in the context of the standard model Lagrangian for the scalar Higgs field interacting with fermions and vector bosons. The measured values of the corresponding couplings are compared to the standard model predictions. The hypothesis of custodial symmetry is tested through the measurement of the ratio of the couplings to the W and Z bosons. All the results are consistent, within their uncertainties, with the expectations for a standard model Higgs boson. Figure not available: see fulltext.
Observation of the rare decay KS→π0e+e Batley, J.R; Kalmus, G.E; Lazzeroni, C ...
Physics letters. B,
12/2003, Letnik:
576, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
A search for the decay KS→π0e+e− has been made by the NA48/1 experiment at the CERN SPS accelerator. Using data collected during 89 days in 2002 with a high-intensity KS beam, 7 events were found ...with a background of 0.15 events. The branching fraction BR(KS→π0e+e−,mee>0.165 GeV/c2)=(3.0+1.5−1.2(stat)±0.2(syst))×10−9 has been measured. Using a vector matrix element and a form factor equal to one, the measurement gives BR(KS→π0e+e−)=(5.8+2.9−2.4)×10−9.
In an earlier paper 1, the background for Ke3 was over estimated due to an erroneous calculation of the electron identification efficiency. The correct ratios of the partial widths involving this ...channel are \(\mathcal{R}_{K e 3 / K2\pi} = 0.2470\pm0.0009\, ({\text{stat}})\pm0.0004\, ({\text{syst}})\) and \(\mathcal{R}_{K \mu3 / Ke3} = 0.663\pm0.003\,({\text{stat}})\pm0.001\,({\text{syst}})\). Assuming the PDG value 2 for the K2π branching ratio, the measured branching fraction of Br (Ke3) continues to exceed the current PDG value 2. The extracted value of |Vus|f+(0) is in agreement with the CKM unitary prediction; thus, our conclusions in 1 do not change.
A measurement of the direct CP violating charge asymmetries of the Dalitz plot linear slopes Ag=(g+-g-)/(g++g-) in K±→π±π+π- and K±→π±π0π0 decays by the NA48/2 experiment at CERN SPS is presented. A ...new technique of asymmetry measurement involving simultaneous K+ and K- beams and a large data sample collected allowed a result of an unprecedented precision. The charge asymmetries were measured to be Acg=(-1.5±2.2)×10-4 with 3.11×109K±→π±π+π- decays, and Ang=(1.8±1.8)×10-4 with 9.13×107K±→π±π0π0 decays. The precision of the results is limited mainly by the size of the data sample.
Using GPGPU techniques and multi-precision calculation we developed the code to study QCD phase transition line in the canonical approach. The canonical approach is a powerful tool to investigate ...sign problem in Lattice QCD. The central part of the canonical approach is the fugacity expansion of the grand canonical partition functions. Canonical partition functions \(Z_n(T)\) are coefficients of this expansion. Using various methods we study properties of \(Z_n(T)\). At the last step we perform cubic spline for temperature dependence of \(Z_n(T)\) at fixed \(n\) and compute baryon number susceptibility \(\chi_B/T^2\) as function of temperature. After that we compute numerically \(\partial\chi/ \partial T\) and restore crossover line in QCD phase diagram. We use improved Wilson fermions and Iwasaki gauge action on the \(16^3 \times 4\) lattice with \(m_{\pi}/m_{\rho} = 0.8\) as a sandbox to check the canonical approach. In this framework we obtain coefficient in parametrization of crossover line \(T_c(\mu_B^2)=T_c\left(c-\kappa\, \mu_B^2/T_c^2\right)\) with \(\kappa = -0.0453 \pm 0.0099\).
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image) Abstract Figure not available: see fulltext. The production of the X(3872) is studied in pp collisions at ... TeV, using ...decays to J/ψπ ^sup +^ pi ^sup -^, where the J/psi decays to two muons. The data were recorded by the CMS experiment and correspond to an integrated luminosity of 4.8 fb^sup -1^. The measurements are performed in a kinematic range in which the X(3872) candidates have a transverse momentum 10<p ^sub T^ <50 GeV and rapidity |y|<1.2. The ratio of the X(3872) and psi(2S) cross sections times their branching fractions into J/ψπ ^sup +^ pi ^sup -^ is measured as a function of p ^sub T^. In addition, the fraction of X(3872) originating from B decays is determined. From these measurements the prompt X(3872) differential cross section times branching fraction as a function of p ^sub T^ is extracted. The pi ^sup +^ pi ^sup -^ mass spectrum of the J/ψπ ^sup +^ pi ^sup -^ system in the X(3872) decays is also investigated.
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