Measurement of differential $$ b\overline{b} $$- and $$ c\overline{c} $$-dijet cross-sections in the forward region of pp collisions at $$ \sqrt{s} $$ = 13 TeV

The inclusive $$ b\overline{b} $$ b b ¯ - and $$ c\overline{c} $$ c c ¯ -dijet production cross-sections in the forward region of pp collisions are measured using a data sample collected with the LHCb detector at a centre-of-mass energy of 13 TeV in 2016. The data sample corresponds to an integrated luminosity of 1.6 fb−1. Differential cross-sections are measured as a function of the transverse momentum and of the pseudorapidity of the leading jet, of the rapidity difference between the jets, and of the dijet invariant mass. A fiducial region for the measurement is defined by requiring that the two jets originating from the two b or c quarks are emitted with transverse momentum greater than 20 GeV/c, pseudorapidity in the range 2.2 < η < 4.2, and with a difference in the azimuthal angle between the two jets greater than 1.5. The integrated $$ b\overline{b} $$ b b ¯ -dijet cross-section is measured to be 53.0 ± 9.7 nb, and the total $$ c\overline{c} $$ c c ¯ -dijet cross-section is measured to be 73 ± 16 nb. The ratio between $$ c\overline{c} $$ c c ¯ - and $$ b\overline{b} $$ b b ¯ -dijet cross-sections is also measured and found to be 1.37 ± 0.27. The results are in agreement with theoretical predictions at next-to-leading order.

Measurements of inclusive jet and dijet cross sections at the Large Hadron Collider

This review discusses the measurements of the inclusive jet and dijet cross section performed by the experimental collaborations at the LHC during what is now being called LHC Run 1 (2009–2013). It summarises some of the experimental challenges and the techniques used in the measurements of jets cross sections during the LHC Run 1.

Recent CMS results on diffraction

Recent CMS results on diffraction are presented. These include the measurements of the soft diffractive cross sections, of the forward rapidity gap cross section, of the diffractive dijet cross section, the measurement of a large rapidity gap in W and Z boson events and the measurement of the pseudorapidity distribution of charged particles in a single diffractive enhanced sample. This last measurement is the first common result of the CMS and TOTEM collaborations. Some prospects of common CMS-TOTEM data taking are also discussed.