32 research outputs found
Real and virtual photons effects in di-lepton production at the LHC
We show the SM prediction of di-lepton production at the LHC where to the
usual Drell-Yan production we add the contribution from Photon-Initiated
processes. We discuss the effects of the inclusion of photon interactions in
the high invariant mass region (TeV region) and their consequences on BSM heavy
Z'-boson searches.Comment: 7 pages, 6 figures, Proceeding of Les Rencontres de Physique de la
Vall\'ee d'Aoste, La Thuile 201
The effect of real and virtual photons in the di-lepton channel at the LHC
We present a study of di-lepton production at the CERN Large Hadron Collider
with a particular focus on the contribution resulting from both real and
virtual photons in the initial state. We discuss the region of phase space in
which the invariant mass of the lepton pair is of the order of several TeV,
where searches for new physics phenomena yielding a di-lepton signature are
presently carried out. We study both the yield and associated uncertainties for
all possible topologies in photon-induced di-lepton production and compare
these with what is expected in the standard Drell-Yan channel, where
quark-antiquark pairs are responsible for the production of lepton pairs. We
analyse the impact of these QED contributions on the expected Standard Model
background and on searches for new physics. In this latter case, we use the
production of an extra heavy -boson predicted by the Sequential
Standard Model (SSM) as a benchmark process.Comment: 9 pages, 5 figure
Complementarity of Lepton-Charge and Forward-Backward Drell-Yan Asymmetries for Precision Electroweak Measurements and Quark Density Determinations
We address the impact of future measurements of charged and neutral current
Drell-Yan (DY) asymmetries and their combination on Parton Distribution
Functions (PDFs) uncertainties. We quantify the reduction of PDF uncertainties
using the QCD tool xFitter. We examine the effects of such reduced PDF errors
on both Standard Model (SM) and Beyond SM (BSM) observables.Comment: 5 pages, 4 figures, contribution to the Proceedings for the XXVIII
International Workshop on Deep-Inelastic Scattering and Related Subjects,
Stony Brook University, New York, USA, 12-16 April 202
Drell-Yan production of multi Z'-bosons at the LHC within Non-Universal ED and 4D Composite Higgs Models
The Drell-Yan di-lepton production at hadron colliders is by far the
preferred channel to search for new heavy spin-1 particles. Traditionally, such
searches have exploited the Narrow Width Approximation (NWA) for the signal,
thereby neglecting the effect of the interference between the additional
Z'-bosons and the Standard Model Z and {\gamma}. Recently, it has been
established that both finite width and interference effects can be dealt with
in experimental searches while still retaining the model independent approach
ensured by the NWA. This assessment has been made for the case of popular
single Z'-boson models currently probed at the CERN Large Hadron Collider
(LHC). In this paper, we test the scope of the CERN machine in relation to the
above issues for some benchmark multi Z'-boson models. In particular, we
consider Non-Universal Extra Dimensional (NUED) scenarios and the 4-Dimensional
Composite Higgs Model (4DCHM), both predicting a multi-Z' peaking structure. We
conclude that in a variety of cases, specifically those in which the leptonic
decays modes of one or more of the heavy neutral gauge bosons are suppressed
and/or significant interference effects exist between these or with the
background, especially present when their decay widths are significant,
traditional search approaches based on the assumption of rather narrow and
isolated objects might require suitable modifications to extract the underlying
dynamics