The Search for New Physics by the Measurement of the Four-Jet Cross-Section at LHC and Tevatron

Abstract

We investigate the possibility to look for new physics by the measurement of the 4-jet cross section at LHC and FNAL. In particular, we consider the model with scalar colour octet and the supersymmetric model with R-parity violation. In both models pair produced new particles decay into 2 jets thus leading to 4-jet events.Therefore, the measurement of the distributions of 4-jet differential cross section on on the invariant dijet masses allows to look for new physics. The main background comes from standard QCD 4-jet events. We find that at LHC it would be possible to discover scalar colour octet particles with a mass ≤ 900 Gev and for FNAL the corresponding bound is 175 Gev.

Fermion dark matter from SO(10) GUTs

“…The simplest of all the benchmark models passing the unification conditions above men- in the literature [71][72][73]. At the LHC one of the contribution comes from the gluon-gluon annihilation into two scalar octets gg → Φ 8,1,0 .…”

“…At the LHC one of the contribution comes from the gluon-gluon annihilation into two scalar octets gg → Φ 8,1,0 . For light scalar octets two gluon and quarkantiquark annihilations into two scalar octets give an additional contribution to the two-jet cross section [71]. There are also effects of the scalar octet on the process pp → 4jets at the LHC, being this one of the best signatures to look for [72].…”

“…Considering this relatively low value of mass for the octet, there should be a chance for Φ 8,1,0 to be within the reach of the current run of the LHC. The study of this scalar octet production has been already covered in the literature [71][72][73]. At the LHC one of the contribution comes from the gluon-gluon annihilation into two scalar octets gg → Φ 8,1,0 .…”

Color octet scalars and highpTfour-jet events at the LHC

“…The complete form of the scalar potential is given in ref. [1]. Constraints considered there yield µ 1.…”

Initial determination of the spins of the gluino and squarks at LHC

“…The QCD interactions of these color octets with the quarks and gluon are completely fixed by gauge invariance. The parton cross sections for pair production of these particles are already calculated in reference [2,33,34,35,36].…”