Angular distributions of the decay B 0 → K * 0 µ + µ − are studied using a sample of proton-proton collisions at √ s = 8 TeV collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 20.5 fb −1 . An angular analysis is performed to determine the P 1 and P 5 parameters, where the P 5 parameter is of particular interest because of recent measurements that indicate a potential discrepancy with the standard model predictions. Based on a sample of 1397 signal events, the P 1 and P 5 parameters are determined as a function of the dimuon invariant mass squared. The measurements are in agreement with predictions based on the standard model.
Image segmentation is a mechanism used to divide an image into multiple segments. It will make image smooth and easy to evaluate. Segmentation process also helps to find region of interest in a particular image. The main goal is to make image more simple and meaningful. Existing segmentation techniques can't satisfy all type of images. This survey addressed various image segmentation techniques, evaluates them and presents the issues related to those techniques.
A peaking structure in the J/ψφ mass spectrum near threshold is observed in B ± → J/ψφK ± decays, produced in pp collisions at √ s = 7 TeV collected with the CMS detector at the LHC. The data sample, selected on the basis of the dimuon decay mode of the J/ψ, corresponds to an integrated luminosity of 5.2 fb −1 . Fitting the structure to an S-wave relativistic Breit-Wigner lineshape above a three-body phase-space nonresonant component gives a signal statistical significance exceeding five standard deviations. The fitted mass and width values are m = 4148.0 ± 2.4 (stat.) ± 6.3 (syst.) MeV and Γ = 28 +15 −11 (stat.) ± 19 (syst.) MeV, respectively. Evidence for an additional peaking structure at higher J/ψφ mass is also reported.Events are chosen using a two-level trigger system. The first level, composed of custom hardware processors, uses information from the muon detectors to select dimuon candidates. The high-level trigger (HLT) runs a special version of the offline software code on a processor farm to select events with nonprompt J/ψ candidates coming from the decays of B mesons.Events containing J/ψ candidates are selected by the HLT dimuon trigger. Because of the increasing LHC instantaneous luminosity, there are two configurations of the HLT, corresponding to two running periods and two distinct data sets. For both data sets, the following require-
B The CMS Collaboration
We present the calibration strategy for the 20 kton liquid scintillator central detector of the Jiangmen Underground Neutrino Observatory (JUNO). By utilizing a comprehensive multiple-source and multiple-positional calibration program, in combination with a novel dual calorimetry technique exploiting two independent photosensors and readout systems, we demonstrate that the JUNO central detector can achieve a better than 1% energy linearity and a 3% effective energy resolution, required by the neutrino mass ordering determination.
Measurement of the CP-violating weak phase φ s and the decay width difference ∆Γ s using the B 0 s → J/ψ φ(1020) decay channel in pp collisions at √ s = 8 TeV Abstract The CP-violating weak phase φ s of the B 0 s meson and the decay width difference ∆Γ s of the B 0 s light and heavy mass eigenstates are measured with the CMS detector at the LHC using a data sample of B 0 s → J/ψ φ(1020) → µ + µ − K + K − decays. The analysed data set corresponds to an integrated luminosity of 19.7 fb −1 collected in pp collisions at a centre-of-mass energy of 8 TeV. A total of 49 200 reconstructed B 0 s decays are used to extract the values of φ s and ∆Γ s by performing a time-dependent and flavourtagged angular analysis of the µ + µ − K + K − final state.The weak phase is measured to be φ s = −0.075 ± 0.097 (stat) ± 0.031 (syst) rad, and the decay width difference is ∆Γ s = 0.095 ± 0.013 (stat) ± 0.007 (syst) ps −1 .
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