DATA FROM V. KHACHATRYAN AND COLLEAGUES ADVANCE KNOWLEDGE IN HIGH ENERGY PHYSICS

Physics Week
April 20, 2010

According to a study from Yerevan, Armenia, "Measurements of inclusive
charged-hadron transverse-momentum and pseudorapidity distributions
are presented for proton-proton collisions at root s = 0.9 and 2.36
TeV. The data were collected with the CMS detector during the LHC
commissioning in December 2009."

"For non-single-diffractive interactions, the average charged-hadron
transverse momentum is measured to be 0.46 +/- 0.01 (stat.) +/- 0.01
(syst.) GeV/c at 0.9 TeV and 0.50 +/- 0.01 (stat.) +/- 0.01 (syst.)
GeV/c at 2.36 TeV, for pseudorapidities between -2.4 and +2.4. At
these energies, the measured pseudorapidity densities in the central
region, dN(ch)/d eta vertical bar(vertical bar eta vertical bar
<0.5), are 3.48 +/- 0.02 (stat.) +/- 0.13 (syst.) and 4.47 +/- 0.04
(stat.) +/- 0.16 (syst.), respectively. The results at 0.9 TeV are
in agreement with previous measurements and confirm the expectation
of near equal hadron production in p<(p)over bar > and pp collisions,"
wrote V. Khachatryan and colleagues.

The researchers concluded: "The results at 2.36 TeV represent the
highest-energy measurements at a particle collider to date."

Khachatryan and colleagues published the results of their research
in the Journal of High Energy Physics (Transverse-momentum and
pseudorapidity distributions of charged hadrons in pp collisions at
root s=0.9 and 2.36 TeV. Journal of High Energy Physics, 2010;(2):41).

For additional information, contact V. Khachatryan, Yerevan Phys Inst,
Yerevan 375036, Armenia.

The publisher of the Journal of High Energy Physics can be contacted
at: Springer, 233 Spring St., New York, NY 10013, USA.

From: Emil Lazarian | Ararat NewsPress