Scalar and vector leptoquark pair production at hadron colliders: Signal and backgrounds

Abstract

We perform a systematic analysis of scalar and vector leptoquark pair production at the Fermilab Tevatron and at the CERN LHC. We evaluate signal expectations and background levels for the processes pp(pp) → 2 jets + e + e − and 2 jets + e+ p T . The Monte Carlo event generator ISAJET is used to simulate the experimental conditions at the current ( √ s = 1.8 TeV, L = 100 pb −1 ) and upgraded (L = 2 fb −1 ) Tevatron as well as the LHC ( √ s = 14 TeV, L = 10 fb −1 ). Depending on the luminosity, and assuming a branching ratio B(LQ → eq) = 0.5, we find a discovery reach up to 170 (255) GeV for scalar leptoquarks at the current (upgraded) Tevatron. Similarly, we find vector leptoquarks to be detectable at masses below 300 (400) GeV depending on the coupling. At the LHC, the discovery reach is enhanced to 1 TeV for scalar leptoquarks and to 1.5 TeV for vectors.

LEPTOQUARK SEARCHES AT HERA AND THE TEVATRON

“…energy of 2 TeV. The ten-event discovery reach is about 235 GeV/c 2 (325 GeV/c 2 ) for 1 fb −1 (10 fb −1 ) of data (68,69). Thus, searches for leptoquarks in the next collider run should cover the ?…”

“…A number of investigators have studied possible leptoquark production at the LHC (38,(69)(70)(71)(72)(73)(74). Detailed studies of the pair production of first-generation leptoquark signals and backgrounds have been performed at the event-generator level with energy smearing to mimic calorimeter response (69,72,73). The dominant backgrounds to the searches arise from QCD processes and tt production.…”

Search for First Generation Leptoquarks in the $e \nu j j$ and $e e j j$ Decay Channels in $p\bar{p}$ Collisions at $\sqrt{s}$ = 1.8-TeV

“…The Tevatron has started running in 2001 at a center of mass energy \IS = 2.0 TeV and expects to collect about 2 fb-1 total luminosity during the first two years and possibly 10 fb-1 before LHC turns on in 2005 [104), [105]. This will allow an improvement in the lep toquark mass limits, assuming that they are not discovered: if one considers a 25% selection efficiency at high mass and without candidate events surviving the selection requirements, then the CDF and D0 experiments should be able to set a lower limit on the scalar lep toquark mass at the 95% confidence level of approximately 300 GeV fc2 (375 GeV fc2 ) for 1 fb-1 (10 fb-1 ) of data.…”

“…The Large Hadron Collider (LHC) machine is currently under construction at CERN: starting in 2005, it will provide pp collisions at a center of mass energy ..JS = 14 TeV and iOO fb -1 of data each year [104], [107]. The ATLAS and CMS experiments are likely to be the most important high energy physics experiments of the decade, precisely because they will be the first experiments whose energy is clearly in the regime of new physics.…”