Measurement of Neutral Strange Particle Production in the Underlying Event in Proton-proton Collisions at Sqrt(s)

Measurement of Neutral Strange Particle Production in the Underlying Event in Proton-proton Collisions at Sqrt(s)
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Total Pages : 35
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ISBN-10 : OCLC:1066366540
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Rating : 4/5 (40 Downloads)

Synopsis Measurement of Neutral Strange Particle Production in the Underlying Event in Proton-proton Collisions at Sqrt(s) by :

Measurements are presented of the production of primary K(S)0 and Lambda particles in proton-proton collisions at sqrt(s) = 7 TeV in the region transverse to the leading charged-particle jet in each event. The average multiplicity and average scalar transverse momentum sum of K(S)0 and Lambda particles measured at pseudorapidities abs(eta)

Strange Particle Production in Pp Collisions at Sqrt(s)

Strange Particle Production in Pp Collisions at Sqrt(s)
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Total Pages : 38
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ISBN-10 : OCLC:1066581936
ISBN-13 :
Rating : 4/5 (36 Downloads)

Synopsis Strange Particle Production in Pp Collisions at Sqrt(s) by :

The spectra of strange hadrons are measured in proton-proton collisions, recorded by the CMS experiment at the CERN LHC, at centre-of-mass energies of 0.9 and 7 TeV. The K0_s, Lambda, and Xi-̂ particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and transverse momentum. The results are compared to other experiments and to predictions of the PYTHIA Monte Carlo program. The transverse momentum distributions are found to differ substantially from the PYTHIA results and the production rates exceed the predictions by up to a factor of three.

Measurement of the Underlying Event Activity Using Charged-particle Jets in Proton-proton Collisions at $\sqrt{s}$

Measurement of the Underlying Event Activity Using Charged-particle Jets in Proton-proton Collisions at $\sqrt{s}$
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Total Pages : 30
Release :
ISBN-10 : OCLC:925450782
ISBN-13 :
Rating : 4/5 (82 Downloads)

Synopsis Measurement of the Underlying Event Activity Using Charged-particle Jets in Proton-proton Collisions at $\sqrt{s}$ by :

A measurement of the underlying event (UE) activity in proton-proton collisions is performed using events with charged-particle jets produced in the central pseudorapidity region).

Measurement of the Prompt J/Psi Pair Production Cross Section in Pp Collisions at Sqrt(s)

Measurement of the Prompt J/Psi Pair Production Cross Section in Pp Collisions at Sqrt(s)
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Total Pages : 141
Release :
ISBN-10 : OCLC:1060524988
ISBN-13 :
Rating : 4/5 (88 Downloads)

Synopsis Measurement of the Prompt J/Psi Pair Production Cross Section in Pp Collisions at Sqrt(s) by : Grant Valentine Riley

The cross section for the prompt production of [J/Psi] meson pairs in proton-proton collisions at √ s[sqrt(s)] = 8 TeV at the LHC from a sample corresponding to an integrated luminosity of 20.2±0.5 fb−1 [inverse femtobarns] has been measured with the CMS detector. It provides unique insight into particle production and proton structure in proton-proton (pp) collisions. The two [J/Psi] mesons are fully reconstructed in their [mu+ mu-] decay. An acceptance region is defined by the individual [J/Psi] transverse momentum p [J/Psi pT] and rapidity y [J/Psi Rapidity]. The total fiducial cross section assuming unpolarized prompt [J/Psi] pair production is found to be [sigma_fid] = 195.7 ± 11.1 (stat) ± 22.1 (syst) ± 5.1 (lumi) ± 2.3 (BF) pb. The differential cross sections for prompt [J/Psi] pair production within this acceptance region are measured in eight event variables. Most predictions for particle production in pp collisions at the LHC assume dominance of single parton (gluon, quark) interactions (SPS) at the leading order perturbation theory. This assumption is tested with the final state measured in this analysis. Significant contributions from next-to-leading order processes and double parton scattering (DPS) are observed. In addition, the single [J/Psi] production cross section is estimated from theory and measured with pp collision data. Single [J/Psi] production is compared to the pair production via DPS and quantified via an effective cross section. This quantity is further compared to several particle pair production processes. In particular, the [J/Psi] pair production probes the contributions of gluons. All particle production measurements with CMS depend on the precise knowledge of the LHC luminosity. A detector, the Pixel Luminosity Telescope, based on solid state technology is used to count charged particle tracks from pp collisions, a measure of the instantaneous luminosity. The measurement is provided online for every crossing of the LHC beams. Tests of sensors and the development work for the detector are presented.