Neutrino induced pion production at MiniBooNE and K2K energies
T. Leitner, O. Buss, U. Mosel, L. Alvarez-Ruso
备注:
To appear in the proceedings of 6th International Workshop on Neutrino-Nucleus Interactions in the Few-GeV Region (NuInt09), Sitges, Spain, 18 - 22 May 2009
We investigate charged and neutral current neutrino-induced incoherent pion production off nuclei within the GiBUU model at energies relevant for the MiniBooNE and K2K experiments. Special attention is paid to the entanglement between measured CCQE and CC1pi+ cross sections. We further give predictions and compare to recent data measured at MiniBooNE.
The hybrid model for electroweak single-pion production (SPP) off the nucleon, presented in [González-Jiménez et al., Phys. Rev. D 95, 113007 (2017)], is extended here to the case of incoherent pion-production on the nucleus. Combining a low-energy model with a Regge approach, this model provides valid predictions in the entire energy region of interest for current and future accelerator-based neutrino-oscillation experiments. The Relativistic Mean-Field model is used for the description of the bound nucleons while the outgoing hadrons are considered as plane waves. This approach, known as Rel…
Pion production is a significant component of the signal in accelerator-based neutrino experiments. Over the last years, the MiniBooNE, T2K and MINERvA collaborations have reported a substantial amount of data on (anti)neutrino-induced pion production on the nucleus. However, a comprehensive and consistent description of the whole data set is still missing. We aim at improving the current understanding of neutrino-induced pion production on the nucleus. To this end, the comparison of experimental data with theoretical predictions, preferably based on microscopic models, is essential to disenta…
The charged-current quasi-elastic (CCQE) scattering of muon neutrinos on a carbon target is analyzed using the relativistic distorted-wave impulse approximation (RDWIA) taking into account the contribution of the two-particle and two-hole meson exchange current ($2p-2h$ MEC) to the weak response functions. A fit the RDWIA+MEC model to the MiniBooNE neutrino data is performed and the best fit value of nucleon axial mass $M_A=1.2 \pm 0.06$ GeV is obtained. We also extract the values of the axial form factor $F_A(Q^2)$ as a function of the squared momentum transfer $Q^2$ from the measured $dσ/dQ^…
[Background] Long-Baseline experiments such as T2K, NOvA or the planned Deep Underground Neutrino Experiment (DUNE) require theoretical descriptions of the complete event in a neutrino-nucleus reaction. Since nuclear targets are used this requires a good understanding of neutrino-nucleus interactions. [Purpose] One of the dominant reaction channels in neutrino-nucleus interactions is pion production. This paper aims for a coherent view on all charged current charged pion production data that are avaible from the experiments MiniBooNE, the near detector experiment at T2K and MINERvA. [Methods] …
Neutrino-induced pion production constitutes an important contribution to neutrino-nucleus scattering cross sections at intermediate energies. A deep understanding of this process is mandatory for a correct interpretation of neutrino-oscillation experiments. We aim at contributing to the ongoing effort to understand the various experimental results obtained by different collaborations in a wide range of energies. In particular, in this work we analyze recent MiniBooNE and MINERvA charged-current neutrino 1-pion production data. We use a relativistic theoretical approach which accounts for reso…
The excess of electron-like events measured by MiniBooNE challenges our understanding of neutrinos and their interactions. We review the status of this open problem and ongoing efforts to resolve it. After introducing the experiment and its results, we consider the main experimental backgrounds and the related physics of neutrino interactions with matter such as quasielastic-like scattering and weak pion production on nucleons and nuclei. Special attention is paid to single photon emission in neutral current interactions and, in particular, its coherent channel. The difficulties to reconcile t…
[Background] The neutrino-nucleus ($νA$) cross section is a major source of systematic uncertainty in neutrino-oscillation studies. A precise $νA$ scattering model, in which multinucleon effects are incorporated, is pivotal for an accurate interpretation of the data. [Purpose] In $νA$ interactions, meson-exchange currents (MECs) can induce two-nucleon ($2N$) knockout from the target nucleus, resulting in a two-particle two-hole (2p2h) final state. They also affect single nucleon ($1N$) knockout reactions, yielding a one-particle one-hole (1p1h) final state. Both channels affect the inclusive s…
Can neutrino-induced photon production explain the low energy excess in MiniBooNE?
这份报告总结了我们对MiniBooNE中中性电流(NC)诱导的光子产生的研究,这是由本实验中的低能量过剩所激发的[A. A. Aquilar-Arevalo et al.(MiniBooNE Collaboration),Phys. Rev. Lett. 98,231801(2007); 103,111801(2009)]。提出了两个反常光子- $Z$玻色子-矢量介子耦合的NC光子产生可能解释这种过剩。然而,我们在中微子和反中微子运行中计算的事件数与以前的MiniBooNE估计是基于他们的π介子生产测量一致。在我们以前的工作中讨论的各种核效应,包括核子费米运动,泡利阻塞,和$Δ$共振加宽的核,考虑。用保守的方法研究了由于两个反常项和核效应引起的不确定度。
The MiniBooNE experiment has reported results from the analysis of $ν_e$ and $\bar ν_e$ appearance searches, which show an excess of signal-like events at low reconstructed neutrino energies, with respect to the expected background. A significant component of this background comes from photon emission induced by (anti)neutrino neutral current interactions with nucleons and nuclei. With an improved microscopic model for these reactions, we predict the number and distributions of photon events at the MiniBooNE detector. Our results are compared to the MiniBooNE in situ estimate and to other theo…
RPA correlations, spectral function and 2p2h (multi-nucleon) effects on charged-current neutrino-nucleus reactions without emitted pions are discussed. We pay attention to the influence of RPA and multi-nucleon mechanisms on the MiniBooNE and MINERvA flux folded differential cross sections, the MiniBooNE flux unfolded total cross section and the neutrino energy reconstruction.
The MiniBooNE experiment reported results from the analysis of $ν_e$ and $\overlineν_e$ appearance searches, which showed an excess of signal-like events at low reconstructed neutrino energies with respect to the expected background. A proposed explanation for this anomaly is based on the existence of a heavy ($\sim 50$~MeV) sterile neutrino. These $ν_h$ would be produced by $ν_μ$ electromagnetic and neutral current interactions. A fraction of them decays radiatively inside the detector. The emitted photon is misidentified as an electron or positron in MiniBooNE. We have investigated the $ν_h$…
Neutrinoproduction of Photons and Pions From Nucleons in a Chiral Effective Field Theory for Nuclei
中微子诱导的光子和π介子从核子和原子核的产生(中微子产生)对于解释中微子振荡实验是重要的,因为它们是MiniBooNE实验中的潜在背景[A. A. Aquilar-Arevalo et al.(MiniBooNE Collaboration),Phys. Rev. Lett. { \bf 100},032301(2008)]。这些过程在中等能量下进行研究,其中Δ(1232)共振变得重要。洛伦兹协变有效场论是本系列研究中所使用的框架,它包含核子、π介子、Δs、等序标量场(σ)和矢量场(ω)以及等序矢量场(ρ)。拉格朗日函数表现出(近似)$SU(2)_L \otimes SU(2)_R$手征对称性的非线性实现,并包含矢量介子优势。在本文中,我们专注于建立框架。解释了顶点和费曼图的功率计数。由于固有的对称性,矢量流是自动守恒的(CVC),轴向矢量流是部分守恒的(PCAC)。为了校准轴向矢量跃迁电流(N $\leftrightarrow$ Δ),核子产生的π介子被用作基准,并与阿贡国家实验室和布鲁克海文国家实验室的泡室数据进行比较。在低能量下,我们的功率计数计划的收敛性进行了研究,和下一个领导阶树级校正被发现是小的。
MiniBooNE [1] and MINERvA [2] charge current π + production data in the Delta region are discussed. It is argued that despite the differences in neutrino flux they measure the same dynamical mechanism of pion production and should be strongly correlated. The correlation is clearly seen in the Monte Carlo simulations done with NuWro generator but is missing in the data. Both normalization and the shape of the ratio of measured differential cross sections in pion kinetic energy are different from the Monte Carlo results, in the case of normalization a discrepancy is by a factor of 1.49.
Some of the recent progress in the physics of pion production induced by neutrinos on nucleons and nuclei is reviewed from a theoretical perspective. The importance of Watson's theorem to reconcile ANL and BNL data with the off-diagonal Goldberger-Treiman relation for the $Δ(1232)$ is discussed. The disagreement between MiniBooNE data and theoretical calculations is presented in the light of the new MINERvA data. The coherent pion production data on $^{12}$C obtained by MINERvA are also compared to different microscopic and PCAC models.
Two-pion production in deuteron-deuteron collisions at low energies
在一个两步模型中,dd -> 4 He π π反应的截面在阈值附近进行了估计,在该模型中,第一次相互作用产生的π介子在随后的相互作用中产生第二个π介子。这种方法很好地描述了Pd -> 3 He pi pi和dd -> 4 He eta反应中2 pi和eta的产生速率,导致与实验相比预测过低。必须寻找替代这一模型和双三角洲模型来解释这些数据。