Bounds on Z′Z^\prime from 3-3-1 model at the LHC energies

The Large Hadron Collider will restart with higher energy and luminosity in 2015. This achievement opens the possibility of discovering new phenomena hardly described by the Standard Model, that is based on two neutral gauge bosons: the photon and the $Z$. This perspective imposes a deep and systematic study of models that predicts the existence of new neutral gauge bosons. One of such models is based on the gauge group $SU(3)_C \times SU(3)_L \times U(1)_N$ called 3-3-1 model for short. In this paper we perform a study with $Z^\prime$ predicted in two versions of the 3-3-1 model and compare the signature of this resonance in each model version. By considering the present and future LHC energy regimes, we obtain some distributions and the total cross section for the process $p + p \longrightarrow \ell^{+} + \ell^{-} + X$. Additionally, we derive lower bounds on $Z^\prime$ mass from the latest LHC results. Finally we analyze the LHC potential for discovering this neutral gauge boson at 14 TeV center-of-mass energy.Comment: 6 pages, 9 figures, 2 table

LHCb; Measurement of the forward-central bbˉb \bar{b} production asymmetry

CDF and D0 collaborations results suggests that the top-quark forward-backward production asymmetry is much larger than the Standard Model (SM) predictions. Measuring the $b \bar{b}$ asymmetry production would provide constraint on the flavor structure of any model that attempts to explain the CDF and D0 results. A measurement of the forward-central (FC) $b\bar{b}$ production asymmetry is presented based on the LHCb data collected in 2011 at $\sqrt{s}$ = 7 TeV corresponding to an integrated luminosity of 1.0 fb$^{-1}$ using selected events that have two identified $b$ jets, one of which is flavor tagged by one muon with high momentum. The FC asymmetry is defined as \begin{align} A^{b \bar{b}}_{FC}=\frac{N(\Delta y > 0)-N(\Delta y 0)+N(\Delta y 100$GeV the expected asymmetry is about$\cal{O}$(0.1 %) where gluon fusion which has no asymmetry is less dominant at high mass