Measurements are presented of the production of primary K0S and Λ particles in proton-proton collisions at √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 K0S and Λ particles measured at pseudorapidities |η|<2 rise with increasing charged-particle jet pT in the range 1–10  GeV/c and saturate in the region 10–50  GeV/c. The rise and saturation of the strange-particle yields and transverse momentum sums in the underlying event are similar to those observed for inclusive charged particles, which confirms the impact-parameter picture of multiple parton interactions. The results are compared to recent tunes of the pythia Monte Carlo event generator. The pythia simulations underestimate the data by 15%–30% for K0S mesons and by about 50% for Λ baryons, a deficit similar to that observed for the inclusive strange-particle production in non-single-diffractive proton-proton collisions. The constant strange- to charged-particle activity ratios with respect to the leading jet pT and similar trends for mesons and baryons indicate that the multiparton-interaction dynamics is decoupled from parton hadronization, which occurs at a later stage.

Measurement of neutral strange particle production in the underlying event in proton-proton collisions at √s=7 TeV

L. Bianchini;MARTINI, LUCA;MESSINEO, ALBERTO MARIA;RIZZI, ANDREA;TONELLI, GUIDO EMILIO;A. C. Marini;
2013-01-01

Abstract

Measurements are presented of the production of primary K0S and Λ particles in proton-proton collisions at √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 K0S and Λ particles measured at pseudorapidities |η|<2 rise with increasing charged-particle jet pT in the range 1–10  GeV/c and saturate in the region 10–50  GeV/c. The rise and saturation of the strange-particle yields and transverse momentum sums in the underlying event are similar to those observed for inclusive charged particles, which confirms the impact-parameter picture of multiple parton interactions. The results are compared to recent tunes of the pythia Monte Carlo event generator. The pythia simulations underestimate the data by 15%–30% for K0S mesons and by about 50% for Λ baryons, a deficit similar to that observed for the inclusive strange-particle production in non-single-diffractive proton-proton collisions. The constant strange- to charged-particle activity ratios with respect to the leading jet pT and similar trends for mesons and baryons indicate that the multiparton-interaction dynamics is decoupled from parton hadronization, which occurs at a later stage.
2013
Chatrchyan, S.; Khachatryan, V.; Sirunyan, A. M.; Tumasyan, A.; Adam, W.; Bergauer, T.; Dragicevic, M.; Eroe, J.; Fabjan, C.; Friedl, M.; Fruehwirth, ...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11568/581693
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