Measurement of pion, kaon and proton production in proton–proton collisions at $$\sqrt{s} = 7$$ s = 7 TeV

Abstract

The measurement of primary , , and production at mid-rapidity ( 0.5) in proton–proton collisions at 7 TeV performed with a large ion collider experiment at the large hadron collider (LHC) is reported. Particle identification is performed using the specific ionisation energy-loss and time-of-flight information, the ring-imaging Cherenkov technique and the kink-topology identification of weak decays of charged kaons. Transverse momentum spectra are measured from 0.1 up to 3 GeV/ for pions, from 0.2 up to 6 GeV/ for kaons and from 0.3 up to 6 GeV/ for protons. The measured spectra and particle ratios are compared with quantum chromodynamics-inspired models, tuned to reproduce also the earlier measurements performed at the LHC. Furthermore, the integrated particle yields and ratios as well as the average transverse momenta are compared with results at lower collision energies.

Baryon production from cluster hadronisation

“…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.…”

“…7 The transverse momentum spectra for π + + π − and p +p as measured by ALICE at √ s = 7 TeV [25] in the very central rapidity region |y| < 0.5 splittings) and use the old colour reconnection model and a run where we use both extensions and the parameters that we obtained from the tuning (new model).…”

“…Surprisingly the − / distribution is able Fig. 8 The transverse momentum spectrum for p +p as measured by ALICE at √ s = 7 TeV [25] in the very central rapidity region |y| < 0.5 to capture the general trend but due to large errors in the high p ⊥ region it is difficult to draw conclusions. We see significant improvement in the description of hadron flavour observables.…”

Methods for separation of deuterons produced in the medium and in jets in high-energy collisions

“…The deuteron spectrum from the model has a similar shape to that observed in data. To see how the proton spectrum from PYTHIA compares to the data, we also plot the p+p spectrum from PYTHIA with the same from data [31]. PYTHIA gives the correct shape for both protons and deuterons.…”

“…We nevertheless expect that this method can describe the qualitative behavior of deuteron production in experimental data and allow tests of experimental techniques for investigating deuteron production. [31] and PYTHIA [28] Perugia 2011 tune [30] and deuteron spectra from [15] and PYTHIA Perugia 2011 with the coalescence afterburner described in the text in p+p collisions at √ s = 7 TeV.…”