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Paper   IPM / Particles / 11563
School of Particles and Accelerator
Title:   Search for Quark Compositeness with the Dijet Centrality Ratio in pp Collisions at sqrt(s)=7 TeV
Author(s):
 1 Hessamaddin Arfaei 2 Hamed Bakhshiansohi 3 Seyed Mohsen Etesami 4 Ali Fahim 5 Majid Hashemi 6 Abideh Jafari 7 Mohsen Khakzad 8 A Mohammadi 9 Mojtaba Mohammadi Najafabadi 10 Saeid Paktinat Mehdiabadi 11 Batool Safarzadeh 12 Maryam Zeinali
Status:   Published
Journal: Phys. Rev. Lett.
No.:  262001
Vol.:  105
Year:  2010
Pages:   22
Supported by:  IPM
Abstract:
A search for quark compositeness in the form of quark contact interactions, based on hadronic jet pairs (dijets) produced in proton-proton collisions at sqrt(s)=7 TeV, is described. The data sample of the study corresponds to an integrated luminosity of 2.9 inverse picobarns collected with the CMS detector at the LHC. The dijet centrality ratio, which quantifies the angular distribution of the dijets, is measured as a function of the invariant mass of the dijet system and is found to agree with the predictions of the Standard Model. A statistical analysis of the data provides a lower limit on the energy scale of quark contact interactions. The sensitivity of the analysis is such that the expected limit is 2.9 TeV; because the observed value of the centrality ratio at high invariant mass is below the expectation, the observed limit is 4.0 TeV at the 95