The CMS Collaboration

30 years of jet quenching

“…Such a weak p T -dependence of the jet transverse energy loss is caused by a combination of effects due to jet-induced medium response, radial expansion and jet flavor (quarks and gluons) composition. The LBT can also explain CMS experimental data [72] on γ-jet distributions as shown in Fig. 5 (left).…”

Large Hadron Collider and Dark Matter

“…The searches have therefore mostly concentrated on gluinos (the superpartners of the gluons, which are present in the proton) and first two generation squarks (the scalar superpartners of the quarks), without success so far, pushing the bounds on these superparticle masses above the TeV (see Aad et al 2013b;Chatrchyan et al 2012d) for published results on the 7 TeV data of 2011, but more recent ones have been presented in conference notes or preprints, e.g. in ATLAS (2012) and in Chatrchyan et al (2013). Nevertheless, there are more general supersymmetric models which allow to accommodate a heavier spectrum and still a neutralino WIMP and DM (Arbey et al 2012a,b;Cahill-Rowley et al 2012a,b), so supersymmetry is not yet excluded.…”

Collision system size scan of collective flows in relativistic heavy-ion collisions

“…To understand these observables in experiments and QGP phase transition, there are also some open questions for small collision systems (such as C + C or O + O collisions) as well as large collision systems (such as Au + Au or Pb + Pb collisions), (1) how to understand transformation coefficient from initial geometry distribution or fluctuation to momentum distribution at final stage in hydrodynamical mechanism [20,[28][29][30]; (2) how to understand similar phenomena for some observables for small systems with high multiplicity and large systems [9,10,[31][32][33][34][35][36][37]; (3) does the matter created in different size of system undergo the similar dy-namical process and have similar viscosity [38,39]?, and the last two questions are closely related. Recently the small system experiments were proposed for RHIC-STAR [40] and LHC-ALICE [41] to study the initial geometry distribution and fluctuations effects on momentum distribution at final stage.…”

“…Two particle correlation (2PC) method with ∆η gap is usually employed to calculate the collective flow coefficients in theoretical analysis and experimental measurements [64][65][66][67][68] . In this work we adopted the 2PC-method introduced in Ref.…”