scholarly journals THE FIRST YEAR OF THE LARGE HADRON COLLIDER: A BRIEF REVIEW

2011 ◽  
Vol 26 (12) ◽  
pp. 843-855
Author(s):  
GREGOR HERTEN

The first year of LHC data taking provided an integrated luminosity of about 35 pb-1 in proton–proton collisions at [Formula: see text]. The accelerator and the experiments have demonstrated an excellent performance. The experiments have obtained important physics results in many areas, ranging from tests of the Standard Model to searches for new particles. Among other results, the physics highlights have been the measurements of the W-, Z-boson and [Formula: see text] production cross-sections, improved limits on supersymmetric and other hypothetical particles and the observation of jet-quenching, elliptical flow and J/ψ suppression in lead–lead collisions at [Formula: see text].

2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Measurements of the fiducial inclusive and differential production cross sections of the Higgs boson in proton-proton collisions at $$ \sqrt{s} $$ s = 13 TeV are performed using events where the Higgs boson decays into a pair of W bosons that subsequently decay into a final state with an electron, a muon, and a pair of neutrinos. The analysis is based on data collected with the CMS detector at the LHC during 2016–2018, corresponding to an integrated luminosity of 137 fb−1. Production cross sections are measured as a function of the transverse momentum of the Higgs boson and the associated jet multiplicity. The Higgs boson signal is extracted and simultaneously unfolded to correct for selection efficiency and resolution effects using maximum-likelihood fits to the observed distributions in data. The integrated fiducial cross section is measured to be 86.5 ± 9.5 fb, consistent with the Standard Model expectation of 82.5 ± 4.2 fb. No significant deviation from the Standard Model expectations is observed in the differential measurements.


2019 ◽  
Vol 790 ◽  
pp. 509-532 ◽  
Author(s):  
A.M. Sirunyan ◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
E. Asilar ◽  
...  

2012 ◽  
Vol 85 (9) ◽  
Author(s):  
L. Adamczyk ◽  
G. Agakishiev ◽  
M. M. Aggarwal ◽  
Z. Ahammed ◽  
A. V. Alakhverdyants ◽  
...  

2011 ◽  
Vol 20 (05) ◽  
pp. 1243-1270 ◽  
Author(s):  
A. I. AHMADOV ◽  
R. M. BURJALIYEV

In this paper, we investigate the next-to-leading order contribution of the higher-twist Feynman diagrams to the large-pT inclusive pion production cross-section in proton–proton collisions and present the general formulae for the higher-twist differential cross-sections in the case of the running coupling and frozen coupling approaches. We compared the resummed next-to-leading order higher-twist cross-sections with the ones obtained in the framework of the frozen coupling approach and leading-twist cross-section. The structure of infrared renormalon singularities of the higher-twist subprocess cross-section and its resummed expression (the Borel sum) are found. It is shown that the resummed result depends on the choice of the meson wave functions used in the calculations. We discuss the phenomenological consequences of possible higher-twist contributions to the meson production in proton–proton collisions in next-to-leading order at RHIC.


Author(s):  
A. M. Sirunyan ◽  
◽  
A. Tumasyan ◽  
W. Adam ◽  
F. Ambrogi ◽  
...  

Abstract Central exclusive and semiexclusive production of "Equation missing" pairs is measured with the CMS detector in proton-proton collisions at the LHC at center-of-mass energies of 5.02 and 13TeV. The theoretical description of these nonperturbative processes, which have not yet been measured in detail at the LHC, poses a significant challenge to models. The two pions are measured and identified in the CMS silicon tracker based on specific energy loss, whereas the absence of other particles is ensured by calorimeter information. The total and differential cross sections of exclusive and semiexclusive central "Equation missing" production are measured as functions of invariant mass, transverse momentum, and rapidity of the "Equation missing" system in the fiducial region defined as transverse momentum "Equation missing" and pseudorapidity "Equation missing". The production cross sections for the four resonant channels "Image missing" , "Equation missing", "Image missing" , and "Image missing" are extracted using a simple model. These results represent the first measurement of this process at the LHC collision energies of 5.02 and 13TeV.


Sign in / Sign up

Export Citation Format

Share Document