We consider the Z polarization asymmetry A_Z=(σ(ZR)−σ(ZL))/(σ(ZR)+σ(ZL)) in the process of associated bZ production at the LHC. We show that in the Standard Model (SM) this quantity is essentially given by its Born approximation, remaining almost unaffected by QCD scales and parton distribution functions variations as well as by electroweak corrections. The theoretical quantity that appears in A_Z is the same that provides the LEP1 Z→bb¯ forward–backward asymmetry, the only measured observable still in some contradiction with the SM prediction. In this sense, A_Z would provide the possibility of an independent verification of the possible SM discrepancy, which could reach, if consistency with LEP1 measurements is imposed, values of the relative ten percent size.

The relevance of polarized bZ production at LHC

PANIZZO, GIANCARLO;VERZEGNASSI, CLAUDIO
2012

Abstract

We consider the Z polarization asymmetry A_Z=(σ(ZR)−σ(ZL))/(σ(ZR)+σ(ZL)) in the process of associated bZ production at the LHC. We show that in the Standard Model (SM) this quantity is essentially given by its Born approximation, remaining almost unaffected by QCD scales and parton distribution functions variations as well as by electroweak corrections. The theoretical quantity that appears in A_Z is the same that provides the LEP1 Z→bb¯ forward–backward asymmetry, the only measured observable still in some contradiction with the SM prediction. In this sense, A_Z would provide the possibility of an independent verification of the possible SM discrepancy, which could reach, if consistency with LEP1 measurements is imposed, values of the relative ten percent size.
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11368/2726288
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