Search results for "MINOS"
showing 10 items of 739 documents
Measurement of the absolute branching fraction for Λc+→Λμ+νμ
2017
Abstract We report the first measurement of the absolute branching fraction for Λ c + → Λ μ + ν μ . This measurement is based on a sample of e + e − annihilation data produced at a center-of-mass energy s = 4.6 GeV , collected with the BESIII detector at the BEPCII storage rings. The sample corresponds to an integrated luminosity of 567 pb − 1 . The branching fraction is determined to be B ( Λ c + → Λ μ + ν μ ) = ( 3.49 ± 0.46 ( stat ) ± 0.27 ( syst ) ) % . In addition, we calculate the ratio B ( Λ c + → Λ μ + ν μ ) / B ( Λ c + → Λ e + ν e ) to be 0.96 ± 0.16 ( stat ) ± 0.04 ( syst ) .
Mainz/PSI Φ-factory design considerations
1991
Abstract Design considerations for a Φ-factory with a Luminosity of the order of 10 33 cm −2 s −1 lead to the concept of a multi-bunch round beam double storage ring with supercoducting solenoids for micro-beta focusing and beam rotation. Simulations of the beam-beam-interaction indicate, that significantly higher beam-beam-parameters may become possible with round beams. A rough draft design of a round beam Φ-factory is presented.
Study of the four-jet anomaly observed at LEP centre-of-mass energies of 130 and 136 GeV
1999
The four-jet events collected by DELPHI during the special LEP run at centre-of-mass energies of 130 and 136 GeV in 1997 with an integrated luminosity of 5.9 pb(-1) are analysed. Their rate and the distributions of their di-jet masses, their smallest jet charges, and their di-jet charge separations all agree well with Standard Model predictions. Thus the hypothesis of pair production of a new particle with a sum of di-jet masses around 105 GeV/c(2) is not supported. The combined result of the four LEP collaborations refuting this hypothesis at over 99% confidence level is also given. (C) 1999 Published by Elsevier Science B.V. All rights reserved.
Search for particles with unexpected mass and charge in Z decays
1993
During 1989 and 1990 over 180 000 hadronic and leptonic events, corresponding to 8 pb-1 of luminosity, were collected by the ALEPH detector in a scan of the Z peak at the e+e- collider LEP. This letter reports the results of a search in these data for particles with unexpected mass and charge by measurement of the ionization energy loss of charged tracks in the ALEPH TPC central tracking detector. The mass limits for the pair production of fractionally charged particles and of heavy, long lived charged particles are extended to 43 GeV/c2 at 90% confidence level. If single production of a heavy particle is considered, the mass limit is extended to more than 70 GeV/c2. RI Perrier, Frederic/A-…
Measurement of CP asymmetries in the decays B0 → K*0 μ+μ- and B+ → K+ μ+μ-
2014
The direct CP asymmetries of the decays B 0 → K *0 μ + μ − and B + → K + μ + μ − are measured using pp collision data corresponding to an integrated luminosity of 3.0 fb−1 collected with the LHCb detector. The respective control modes B 0 → J/ψK *0 and B + → J/ψK + are used to account for detection and production asymmetries. The measurements are made in several intervals of μ + μ − invariant mass squared, with the ϕ(1020) and charmonium resonance regions excluded. Under the hypothesis of zero CP asymmetry in the control modes, the average values of the asymmetries are ACP(B0→K∗0μ+μ−)=−0.035±0.024±0.003,ACP(B+→K+μ+μ−)=0.012±0.017±0.001, where the first uncertainties are statistical and the …
Search for displaced vertices arising from decays of new heavy particles in 7 TeV pp collisions at ATLAS
2012
We present the results of a search for new, heavy particles that decay at a significant distance from their production point into a final state containing charged hadrons in association with a high-momentum muon. The search is conducted in a pp-collision data sample with a center-of-mass energy of 7 TeV and an integrated luminosity of 33 pb[superscript −1] collected in 2010 by the ATLAS detector operating at the Large Hadron Collider. Production of such particles is expected in various scenarios of physics beyond the standard model. We observe no signal and place limits on the production cross-section of supersymmetric particles in an R-parity-violating scenario as a function of the neutral…
Measurement of the mass of the W boson using direct reconstruction at √s = 183 GeV
1999
From data corresponding to an integrated luminosity of 53.5 pb(-1) taken during the 183 GeV run in 1997, DELPHI has measured the W mass from direct reconstruction of WW --> lq (q) over bar and WW --> q (q) over bar q (q) over bar events. Combining these channels, a value of m(w) = 80.238 +/- 0.154(stat) +/- 0.035(syst) +/- 0.035(fsi) +/- 0.021 (LEP) GeV/c(2) is obtained, where fsi denotes final state interaction. Combined with the W mass obtained by DELPHI from the WW production cross-section and with the direct measurement at 172 GeV this leads to a measured value of m(w) = 80.270 +/- 0.137(stat) +/- 0.031(syst) +/- 0.030(fsi) +/- 0.021(LEP)GeV/c(2), in good agreement with the Standard Mod…
Search for the Standard Model Higgs boson at LEP in the year 2000
2001
Searches for the Standard Model Higgs boson have been performed in the data collected by the DELPHI experiment at LEP in the year 2000 at centre-of-mass energies between 200 and 209 GeV corresponding to a total integrated luminosity of 224 pb^{-1}. No evidence for a Higgs signal is observed in the kinematically accessible mass range, and a 95% CL lower mass limit of 114.3 GeV/c^2 is set, to be compared with an expected median limit of 113.5 GeV/c^2 for these data.
Search for Heavy, Long-Lived Neutralinos that Decay to Photons at CDF II Using Photon Timing
2008
We present the results of the first hadron collider search for heavy, long-lived neutralinos that decay via lightest neutralino to gamma gravitino in gauge-mediated supersymmetry breaking models. Using an integrated luminosity of $570\pm34 pb^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}=1.96$ TeV, we select $\gamma$+jet+missing transverse energy candidate events based on the arrival time of a high-energy photon at the electromagnetic calorimeter as measured with a timing system that was recently installed on the CDF II detector. We find 2 events, consistent with the background estimate of 1.3$\pm$0.7 events. While our search strategy does not rely on model-specific dynamics, we set cross sec…
Enhancement of the double Higgs production via leptoquarks at the LHC
2021
Measurements of single Higgs production and its decays are in good agreement with the Standard Model. There is still room for large modifications in double Higgs production at LHC, though these effects may be correlated with large corrections to other observables, in particular single Higgs production. In this work we address the issue of enhancing double Higgs production in the presence of scalar leptoquarks while satisfying all experimental constraints. We show at leading order that including more than one species of leptoquarks, large cubic interactions with the Higgs can lead to sizable enhancement of di-Higgs production cross section at LHC, while at the same time keeping other Higgs o…