Resonance production by neutrinos: The second resonance region

Lalakulich, O.; Paschos, E. A.; Piranishvili, Giorgi

doi:10.1103/physrevd.74.014009

Cited by 159 publications

(338 citation statements)

References 33 publications

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“…(29) and (44). There are some other W + N N → N N π mechanisms which should be taken into account, as well as the contribution of higher resonances [58]. Though small, also kaon [59], hyperon [60] and two pion [61] production channels should be considered to end up with a robust theoretical model above 1 GeV.…”

Section: Resultsmentioning

confidence: 99%

Inclusive charged-current neutrino-nucleus reactions

2011

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We present a model for weak CC induced nuclear reactions at energies of interest for current and future neutrino oscillation experiments. This model is a natural extension of the work of Refs. [1,2], where the QE contribution to the inclusive electron and neutrino scattering on nuclei was analyzed. The model is based on a systematic many body expansion of the gauge boson absorption modes that includes one, two and even three body mechanisms, as well as the excitation of ∆ isobars. The whole scheme has no free parameters, besides those previously adjusted to the weak pion production off the nucleon cross sections in the deuteron, since all nuclear effects were set up in previous studies of photon, electron and pion interactions with nuclei. We have discussed at length the recent charged current quasi-elastic MiniBooNE cross section data, and showed that two nucleon knockout mechanisms are essential to describe these measurements.

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Section: Resultsmentioning

confidence: 99%

Inclusive charged-current neutrino-nucleus reactions

2011

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“…In the case of the vector F γZ 2 structure function, conservation of the two vector currents requires F γZ 2 ∼ Q 2 as Q 2 → 0. By contrast, F γZ 3 depends on both vector and axial-vector currents, and the nonconservation of the latter means that no similar constraint exists [16].…”

Section: Dis (Qmentioning

confidence: 99%

“…For the resonance contributions ✷ A(res) γZ from region (ii), we use the parametrizations of the transition form factors from Lalakulich et al [16], but with modified isospin factors appropriate to γZ. These form factors have been fitted to the Jefferson Lab pion electroproduction data (vector part) and pion production data in ν andν scattering at ANL, BNL and Serpukhov (axialvector part).…”

Section: Dis (Qmentioning

confidence: 99%

New Formulation ofγZBox Corrections to the Weak Charge of the Proton

2011

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We present a new formulation of one of the major radiative corrections to the weak charge of the proton -that arising from the axial-vector hadron part of the γZ box diagram, ℜe ✷ A γZ . This formulation, based on dispersion relations, relates the γZ contributions to moments of the F γZ 3 interference structure function. It has a clear connection to the pioneering work of Marciano and Sirlin, and enables a systematic approach to improved numerical precision. Using currently available data, the total correction from all intermediate states is ℜe ✷ A γZ = 0.0044(4) at zero energy, which shifts the theoretical estimate of the proton weak charge from 0.0713(8) to 0.0705(8). The energy dependence of this result, which is vital for interpreting the Q weak experiment, is also determined.As modern parity-violating (PV) experiments press to ever improving levels of precision, they remain a vital complement to direct tests of the Standard Model at the high energy frontier. The classic example of this, involving precise measurements of parity violation in atoms, led to a remarkably accurate determination of sin 2 θ W . A complementary PV electron-proton scattering measurement underway by the Q weak Collaboration [1] at Jefferson Lab has the potential to increase the mass scale associated with new physics to 2 TeV or higher, provided that the critical radiative corrections are under control. In this Letter we present a new formulation of the important γZ radiative corrections which allows for their controlled, systematic evaluation.Including electroweak radiative corrections, the proton weak charge is defined, at zero electron energy E and zero momentum transfer, as [2]where sin 2 θ W (0) is the weak mixing angle at zero momentum, and the corrections ∆ρ, ∆ e and ∆ ′ e are given in [2] and references therein. The contributions ✷ W W and ✷ ZZ arise from the W W and ZZ box and crossed-box diagrams, and can be computed perturbatively. They are expected to be energy independent for electron scattering in the GeV range. By contrast, the γZ interference correction ✷ γZ (E) depends on physics at both short and long distance scales.In the classic work of Marciano and Sirlin (MS) [3], ✷ γZ (0) was evaluated in a quark model-inspired loop calculation using either a "perturbative" (p) or a "nonperturbative" (np) ansatz,where v e (M 2 Z ) = (1 − 4ŝ 2 ), andŝ 2 ≡ sin 2 θ W (M 2 Z ) = 0.23116 in the MS scheme [4].The perturbative ansatz [3]is the free quark model result, with m a hadronic mass scale, and shows the leading-log behavior. For the nonperturbative ansatz, B np = K m + L m is the sum of a long-distance part, L m , and a short-distance part, K m , withHere m is a mass scale representing the onset of asymptotic behavior at large loop momenta, and the factor (1 − α s (u)/π) is the lowest-order correction induced by the strong interactions. In Ref.[3] L m is taken to be the elastic nucleon (Born) contribution, which is evaluated to be 2.04 using the same dipole form factors for both the electromagnetic and axial-vector coupling. MS...

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“…[34] for the electron analogue eN → e ′ N ′ π reaction. Most previous studies [35,36,37,38,39,40,41,42,43] of these processes considered only the dominant ∆ pole mechanism in which the neutrino excites a ∆(1232) resonance that subsequently decays into N π. In our model we have also included background terms required by chiral symmetry (See Fig.…”

Section: Introductionmentioning

confidence: 99%

Theoretical study of neutrino-induced coherent pion production off nuclei at T2K and MiniBooNE energies

Hernández²,

et al. 2009

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We have developed a model for neutrino-induced coherent pion production off nuclei in the energy regime of interest for present and forthcoming neutrino oscillation experiments. It is based on a microscopic model for pion production off the nucleon that, besides the dominant ∆ pole contribution, takes into account the effect of background terms required by chiral symmetry. Moreover, the model uses a reduced nucleon-to-∆ resonance axial coupling, which leads to coherent pion production cross sections around a factor two smaller than most of the previous theoretical estimates. In the coherent production, the main nuclear effects, namely medium corrections on the ∆ propagator and the final pion distortion, are included. We have improved on previous similar models by taking into account the nucleon motion and employing a more sophisticated optical potential. As found in previous calculations the modification of the ∆ self-energy inside the nuclear medium strongly reduces the cross section, while the final pion distortion mainly shifts the peak position to lower pion energies. The angular distribution profiles are not much affected by nuclear effects. Nucleon motion increases the cross section by ∼ 15% at neutrino energies of 650 MeV, while Coulomb effects on charged pions are estimated to be small. Finally, we discuss at length the deficiencies of the Rein-Sehgal pion coherent production model for neutrino energies below 2 GeV, and in particular for the MiniBooNE and T2K experiments. We also predict flux averaged cross sections for these two latter experiments and K2K.

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Resonance production by neutrinos: The second resonance region

Cited by 159 publications

References 33 publications

Inclusive charged-current neutrino-nucleus reactions

Inclusive charged-current neutrino-nucleus reactions

New Formulation ofγZBox Corrections to the Weak Charge of the Proton

Theoretical study of neutrino-induced coherent pion production off nuclei at T2K and MiniBooNE energies

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