scholarly journals Energy calibration and resolution of the CMS electromagnetic calorimeter in pp collisions at √s= 7 TeV

2013 ◽  
Vol 8 (09) ◽  
pp. P09009-P09009 ◽  
2016 ◽  
Vol 40 ◽  
pp. 1660024
Author(s):  
Christopher J. Dilks

Longitudinally polarized [Formula: see text] scattering experiments provide access to gluon polarization via measurement of the double helicity asymmetry, [Formula: see text]. At the completion of the 2013 RHIC running period, a significant dataset of [Formula: see text]s corresponding to an integrated luminosity of 46 [Formula: see text] (2012) and 8 [Formula: see text] (2013) produced from polarized [Formula: see text] scattering at [Formula: see text] GeV with an average beam polarization of approximately [Formula: see text] was acquired. The [Formula: see text] kinematics were measured via isolation cones by the STAR Forward Meson Spectrometer, an electromagnetic calorimeter covering a forward pseudorapidity range of [Formula: see text]. The asymmetric [Formula: see text] subprocess becomes more dominant in this forward region than in the midrapidity region; furthermore, asymmetry measurements in the forward region are sensitive to low-[Formula: see text] gluons. Progress on [Formula: see text] determined from forward [Formula: see text] events, complementing previous midrapidity measurements, are presented.


2020 ◽  
Vol 35 (34n35) ◽  
pp. 2044011
Author(s):  
Amina Zghiche

The CMS Electromagnetic Calorimeter (ECAL), is a high granularity lead tungstate (PbWO4) crystal calorimeter operating at the CERN LHC. The ECAL performance has been crucial in the discovery and subsequent characterization of the Higgs boson. The original ECAL design considerations, and the improvements to the energy reconstruction and energy calibration algorithms to cope with the LHC Run II are described. For the High-Luminosity LHC (HL-LHC) upgrades to ECAL are necessary. The crystals in the barrel region will be retained, defining the HL-LHC CMS barrel electromagnetic calorimeter ECAL. The readout electronics will be upgraded and operating at lower temperatures, to maintain the required performance of ECAL from 2027 onwards. The new readout electronics, the timing resolution and the electron and photon reconstruction efficiencies and energy resolution expected for HL-LHC are presented. The performance relevant to a number of key Higgs decay channels is reported.


2018 ◽  
Vol 182 ◽  
pp. 02064 ◽  
Author(s):  
Anisa Khatun ◽  

The increase of hard probe production as a function of the charged particle multiplicity in proton-proton and proton-lead collisions is considered to be an interesting observable for the study of multiple parton interactions. In the present work, the correlation between J/Ψ production and charged particle multiplicity has been reviewed in pp collisions at √s = 7 and 13 TeV and p-Pb collisions at √sNN = 5.02 TeV at mid- and forward rapidities. The J/√ measurement in pp collisions at √s = 13 TeV using events triggered by the ALICE electromagnetic calorimeter at midrapidity is discussed in this report, too. An increment of the relative J/Ψ yields has been observed as a function of the multiplicity. The results have also been compared to theoretical model predictions.


2021 ◽  
Vol 81 (12) ◽  
Author(s):  
S. Acharya ◽  
D. Adamová ◽  
A. Adler ◽  
G. Aglieri Rinella ◽  
M. Agnello ◽  
...  

AbstractWe report on the inclusive $$\text {J}/\psi $$ J / ψ production cross section measured at the CERN Large Hadron Collider in proton–proton collisions at a center-of-mass energy $$\sqrt{s}~=~13$$ s = 13  TeV. The $$\text {J}/\psi $$ J / ψ mesons are reconstructed in the $$\text {e}^{+}\text {e}^{-}$$ e + e - decay channel and the measurements are performed at midrapidity ($$|y|<0.9$$ | y | < 0.9 ) in the transverse-momentum interval $$0<p_{\mathrm{T}} <40$$ 0 < p T < 40  GeV/$$c$$ c , using a minimum-bias data sample corresponding to an integrated luminosity $$L_{\text {int}} = 32.2~\text {nb}^{-1}$$ L int = 32.2 nb - 1 and an Electromagnetic Calorimeter triggered data sample with $$L_{\text {int}} = 8.3~\mathrm {pb}^{-1}$$ L int = 8.3 pb - 1 . The $$p_{\mathrm{T}}$$ p T -integrated $$\text {J}/\psi $$ J / ψ production cross section at midrapidity, computed using the minimum-bias data sample, is $$\text {d}\sigma /\text {d}y|_{y=0} = 8.97\pm 0.24~(\text {stat})\pm 0.48~(\text {syst})\pm 0.15~(\text {lumi})~\mu \text {b}$$ d σ / d y | y = 0 = 8.97 ± 0.24 ( stat ) ± 0.48 ( syst ) ± 0.15 ( lumi ) μ b . An approximate logarithmic dependence with the collision energy is suggested by these results and available world data, in agreement with model predictions. The integrated and $$p_{\mathrm{T}}$$ p T -differential measurements are compared with measurements in pp collisions at lower energies and with several recent phenomenological calculations based on the non-relativistic QCD and Color Evaporation models.


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