August 28, 2011 to September 2, 2011
US/Central timezone
Slides available on Indico -- there are no formal proceedings

$Z'$ Bosons at Colliders: a Bayesian Viewpoint

Aug 29, 2011, 12:35 PM
D: Wilson Hall 1 North

D: Wilson Hall 1 North

Unified models Parallel Session 3


Dr Eduardo Rojas (Instituto de Física Universidad Nacional Autónoma de México)


We revisit the CDF data on di-muon production to impose constraints on a large class of $Z'$ bosons occurring in a variety of $E_6$ GUT based models. For this we suggest an alternative statistical analysis method which ultimately allows to straightforwardly (i)~vary the gauge coupling strength, $g'$, of the underlying $U(1)'$; (ii)~include interference effects with the $Z'$ amplitude (which are especially important for large $g'$); (iii)~smoothly vary the $U(1)'$ charges; (iv)~combine these data with the electroweak precision constraints, as well as with other observables obtained from colliders such as LEP~2 and the LHC; and (v)~find preferred regions in parameter space once an excess is seen. Our method yields limits generally differing by only a few percent from the CDF ones when we follow their approach. We also analyze the dependence of these limits on various factors contributing to the production cross-section, showing that currently systematic and theoretical uncertainties play a relatively minor r$\hat{\rm o}$le. One general result is that interference effects are quite relevant if one aims at discriminating between models. We use a Bayesian method to project lower limits on the $Z'$ mass for the Tevatron and for a number of actual and hypothetical reference energies and luminosities for the LHC. Finally, we show the full classification of the $E_{6}$ $Z'$ models with integer charges.

Primary authors

Dr Eduardo Rojas (Instituto de Física Universidad Nacional Autónoma de México) Dr Jens Erler (Instituto de Fisica Universidad Nacional Autónoma de México)


Paul Langacker (School of Natural Sciences, Institute for Advanced Study, \\ Einstein Drive, Princeton, NJ 08540, USA) Shoaib Munir (Department of Physics, COMSATS Institute of Information Technology, \\ Defence Road, Lahore-54000, Pakistan)

Presentation materials