• Energy Research

Transverse momentum spectra of charged pions, kaons, and protons are measured in proton-proton collisions at sqrt(s) = 13 TeV with the CMS detector at the LHC. The particles, identified via their energy loss in the silicon tracker, are measured in the transverse momentum range of pt ~ 0.1-1.7 GeV and rapidities abs(y) < 1. The pt spectra and integrated yields are compared to previous results at smaller sqrt(s) and to predictions of Monte Carlo event generators. The average pt increases with particle mass and charged particle multiplicity of the event. Comparisons with previous CMS results at sqrt(s) = 0.9, 2.76, and 7 TeV show that the average pt and the ratios of hadron yields feature very similar dependences on the particle multiplicity in the event, independently of the center-of-mass energy of the pp collision. Replaced with the published version. Added the journal reference and DOI. All the figures and tables, including additional supplemental figures, can be found at http://cms-results.web.cern.ch/cms-results/public-results/publications/FSQ-16-004 (CMS Public Pages)

Abstract A description is presented of the algorithms used to reconstruct energy deposited in the CMS hadron calorimeter during Run 2 (2015–2018) of the LHC. During Run 2, the characteristic bunch-crossing spacing for proton-proton collisions was 25 ns, which resulted in overlapping signals from adjacent crossings. The energy corresponding to a particular bunch crossing of interest is estimated using the known pulse shapes of energy depositions in the calorimeter, which are measured as functions of both energy and time. A variety of algorithms were developed to mitigate the effects of adjacent bunch crossings on local energy reconstruction in the hadron calorimeter in Run 2, and their performance is compared.

We determine the strong coupling constant alphas and its energy dependence from the pT dependence of the inclusive jet cross section in ppbar collisions at sqrt(s)=1.96 TeV. The strong coupling constant is determined over the transverse momentum range 50 < pT < 145 GeV. Using perturbative QCD calculations to order O(alphas^3) combined with O(alphas^4) contributions from threshold corrections, we obtain alphas(MZ) = 0.1161 +0.0041 -0.0048. This is the most precise result obtained at a hadron-hadron collider. 7 pages with 1 figure and 1 table; updated to reflect published version