Strange particle production in pp collisions at $ \sqrt {s} = 0.9 $ and 7 TeV

Abstract

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 K 0 S , Λ, and Ξ − particles and their antiparticles are reconstructed from their decay topologies and the production rates are measured as functions of rapidity and transverse momentum, p T . The results are compared to other experiments and to predictions of the Pythia Monte Carlo program. The p T 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 V 0 production ratios in pp collisions at $ \sqrt {s} = 0.9 $ and 7 TeV

“…Excellent agreement is observed between results at both √ s = 0.9 and 7 TeV as well as with results from STAR at √ s = 0.2 TeV. The measured ratios are also consistent with results published by ALICE [2] and CMS [3].…”

Fractal Structure of Hadrons: Experimental and Theoretical Signatures

“…All the results approach Hagedorn's results as q → 1. The resulting values for q and T support the above findings of a constant temperature and entropic index, regardless of the collision energy (as long as it is above approximately 1 TeV) or the particle species [44][45][46][47][48][49][50][51][52][53][54][55][56][57].…”

Baryon production from cluster hadronisation

“…15 we show the ratio of the single strange particles ( +¯ )/2K 0 s and the ratio of p +p/(π + + π − ) which do Fig. 12 The − p ⊥ distribution as measured by CMS at √ s = 7 TeV [29] not contain any strange quarks. In both cases Herwig is not able to describe the data correctly.…”

“…We exploit the freedom one is given by LEP observables for the probability to select a strange quark during cluster fission PwtSquark and additionally allow non-perturbative gluon splitting into strange quarks with a given probability SplitPwtSquark. In a second tuning procedure we consider these two additional parameters and also tune to the p ⊥ distribution of the π + π − , K + + K − , p +p yields in inelastic pp collisions at 7 TeV [25] and the p ⊥ distribution of [29]. The parameter values that were obtained in the tuning are listed in Table 2.…”

“…10, 11, 12, 13 we compare the model to √ s = 7 TeV data from CMS [29] for the strange flavour observables of K 0 S , and − . The new model improves the description for all observables published in this analysis.…”