Dijet Cross Sections in Proton-proton collisions at √s = 200 GeV

Tai Sakuma

Preliminary Results

The dijet cross sections were measured using a data sample of 5.4 pb^-1 in proton-proton collisions at 200 GeV. The cross sections were measured at the mid-rapidity |η| ≤ 0.8 as a function of dijet mass M_jj.

The dijet cross sections were estimated with the formula:

J is the dijet yields at the detector level. C is the correction factors which correct the dijet yields to the hadron level. The correction factors C are estimated from the MC events as bin-by-bin ratios of the dijet yields at the detector level and at the hadron level. ΔM_jjΔη₃Δη₄ normalizes the cross sections to per unit space volume.

The major systematic uncertainty was due to the uncertainty on the jet energy scale (JES). Because the M_jj dependence is steeply decreasing, the uncertainty of the cross section is very sensitive to systematic uncertainty on the JES.

The figures show the preliminary results of the dijet cross section measurements. The measured dijet cross sections are well described by the theory. This indicates that measured A_LL as well can be interpreted in the same theory and suggests ways to constrain the polarized gluon distributions from dijet A_LL.

Analysis Detail

Please, visit this site for the detail: http://people.physics.tamu.edu/sakuma/star/jets/c100923_dijets/s0000_index_001/prelim.php