PCAC and the Deficit of Forward Muons in pi^+ Production by Neutrinos

Simple item page
dc.creatorRein, D.
dc.creatorSehgal, L. M.
dc.date2006-06-18
dc.date2007-10-15
dc.date.accessioned2026-07-07T11:05:08Z
dc.date.available2026-07-07T11:05:08Z
dc.descriptionThe K2K experiment, using a fine-grained detector in a neutrino beam of energy $<E> \sim 1.3 \mathrm{GeV}$ has observed two-track events that can be interpreted as a coherent reaction $ν_μ+ \N \to μ^- + \N + π^+ (\N = \rm{C}^{12})$ or an incoherent process $ν_μ+ (p,n) \to μ^- + π^+ + (p,n)$, the final nucleon being unobserved. The data show a significant deficit of forward-going muons in the interval $Q^2 \lesssim 0.1 \rm{GeV}^2$, where a sizeable coherent signal is expected. We attempt an explanantion of this effect, using a PCAC formula that includes the effect of the non-vanishing muon mass. A suppression of about 25 % is caused by a destructive interference of the axial vector and pseudoscalar (pion-exchange) amplitudes. The incoherent background is also reduced by 10 - 15 %. As a consequence the discrepancy between theory and observation is significantly reduced.
dc.description4 pages including 1 figure, changes in abstract and text; version to appear in Phys.Lett. B
dc.identifierhttps://arxiv.org/abs/hep-ph/0606185
dc.identifierhttp://arxiv.org/abs/hep-ph/0606185
dc.identifierPhys.Lett.B657:207-209,2007
dc.identifierdoi:10.1016/j.physletb.2007.10.025
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/189116
dc.subjectHigh Energy Physics - Phenomenology
dc.titlePCAC and the Deficit of Forward Muons in pi^+ Production by Neutrinos
dc.typetext

Files

Collections

arXiv