Charged Pion Production Research Articles

First measurement of the cross section for νμ and ν¯μ induced single charged pion production on argon using ArgoNeuT

We report on the first cross section measurement of charged-current single charged pion production by neutrinos and antineutrinos on argon. This analysis was performed using the ArgoNeuT detector exposed to the NuMI beam at Fermilab. The measurements are presented as functions of muon momentum, muon angle, pion angle, and angle between muon and pion. The flux-averaged cross sections are measured to be $2.7\pm0.5(stat)\pm0.5(syst) \times 10^{-37} \textrm{cm}^{2}/\textrm{Ar}$ for neutrinos at a mean energy of 9.6 GeV and $8.4\pm0.9(stat)^{+1.0}_{-0.8}(syst) \times 10^{-38} \textrm{cm}^{2}/\textrm{Ar}$ for antineutrinos at a mean energy of 3.6 GeV with the charged pion momentum above 100 MeV/$c$. The results are compared with several model predictions.

Event selection for the measurement of the charged current muon antineutrino single pion production cross section in the T2K near detector

Event selection for the measurement of the charged current muon antineutrino single pion production cross section in the T2K near detector

Modeling neutrino-induced charged pion production on water at T2K kinematics

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 disentangle the different reaction mechanisms involved in the process. To describe single-pion production (SPP) we use a hybrid model that combines a low- and a high-energy approach. The low-energy model (LEM) contains resonances and background terms. At high invariant masses, a high-energy model based on a Regge approach is employed. The model is implemented in the nucleus using the relativistic plane wave impulse approximation (RPWIA). We present a comparison of the hybrid-RPWIA and LEM with the recent neutrino-induced charged current $1\pi^+$ production cross section on water reported by T2K. In order to judge the impact of final-state interactions (FSI) we confront our results with those of the NuWro Monte Carlo generator. The hybrid-RPWIA model and NuWro compare favorably to the data, albeit that FSI are not included in the former. These results complement our previous work [Phys. Rev. D 97, 013004 (2018)] where we compared the models to the MINERvA and MiniBooNE $1\pi^+$ data. The hybrid-RPWIA model tends to overpredict both the T2K and MINERvA data in kinematic regions where the largest suppression due to FSI is expected, and agrees remarkably well with the data in other kinematic regions. On the contrary, the MiniBooNE data is underpredicted over the whole kinematic range.

Measurement of total and differential cross sections of neutrino and antineutrino coherent π± production on carbon

Neutrino induced coherent charged pion production on nuclei, $\overline{\nu}_\mu A\to\mu^\pm\pi^\mp A$, is a rare inelastic interaction in which the four-momentum squared transfered to the nucleus is nearly zero, leaving it intact. We identify such events in the scintillator of MINERvA by reconstructing |t| from the final state pion and muon momenta and by removing events with evidence of energetic nuclear recoil or production of other final state particles. We measure the total neutrino and antineutrino cross sections as a function of neutrino energy between 2 and 20 GeV and measure flux integrated differential cross sections as a function of $Q^2$, $E_\pi$ and $\theta_\pi$. The $Q^2$ dependence and equality of the neutrino and anti-neutrino cross-sections at finite $Q^2$ provide a confirmation of Adler's PCAC hypothesis.

Partial and full inelasticity coefficients in 16Op-collisions at 3.25AGeV/c

The partial inelasticity coefficients of baryon fragments of oxygen nuclei and pions were investigated and the full inelasticity coefficient was determined for the first time in [Formula: see text] collisions at [Formula: see text]. The fraction of kinetic energy of incident proton in [Formula: see text] collisions at [Formula: see text] spent on formation of all the baryon fragments and production of charged and neutral pions was found. The experimental results were compared with those obtained in other experiments at high energies. The experimental full inelasticity coefficient in [Formula: see text] collisions at [Formula: see text] was reproduced well by calculations within the framework of Glauber model of multiple scatterings in hadron–nucleus collisions.

Muon-neutrino-induced charged-current pion production on nuclei

[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] Pion production is treated through excitations of nucleon resonances, including background terms, and deep inelastic scattering. The final state interactions of the produced pions are described within the Giessen-Boltzmann-Uehling-Uhlenbeck (GiBUU) implementation of quantum-kinetic transport theory. [Results] Results are given for MiniBooNE, the near detector experiment at T2K and for MINERvA. While the theoretical results for MiniBooNE differ from the data both in shape and magnitude, their agreement both with the T2K and the MINERvA data is good for all pion and lepton observables. Predictions for pion spectra are shown for MicroBooNE and NOvA. [Conclusions] Based on the GiBUU model of lepton-nucleus interactions a consistent, good theoretical description of CC charged pion production data from the T2K ND and the MINERvA experiments is possible, without any parameter tunes. The MiniBooNE data cannot be reproduced.

Correlations between production of charged pions and formation of light nuclei in 16Op collisions at 3.25AGeV/c

Correlations between production of charged pions and formation of light nuclei in collisions of oxygen nuclei with protons at [Formula: see text][Formula: see text]GeV/[Formula: see text] were investigated. It was deduced that the mechanisms of formation of light fragments with [Formula: see text] and the processes of generation of charged pions do not depend on each other.

Rapidity dependence of charged pion production at relativistic energies using Tsallis statistics

Transverse momentum distributions of charged pions produced in Au+Au collisions at 62.4GeV, 130GeV, 200GeV, Cu+Cu and d+Au collisions at 200GeV, p+p collisions at 62.4 and 200GeV and Pb+Pb collisions at 17.3GeV are studied using the Tsallis distribution as a parametrization. The non-extensivity parameter and Tsallis volume increase with energy, while the Tsallis temperature shows a decrease at higher energies. Using BRAHMS $ p_T$ spectra obtained in Au+Au collisions at 62.4GeV and 200GeV, Tsallis fit parameters are obtained on a very wide rapidity range. Results are compared with p+p and Cu+Cu data and changes of Tsallis parameters with rapidity and energy are investigated. We found that non-extensivity parameter q shows a decrease from midrapidity to forward rapidities for all the studied systems. Tsallis volume, V , increases with the system size from p+p, Cu+Cu to Au+Au, both in central rapidity region and at forward rapidities. The values of temperatures increase with rapidity, but the $ T/\cosh(y)$ ratio is constant as a function of rapidity.

First measurement of the muon neutrino charged current single pion production cross section on water with the T2K near detector

The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\sim}0.8$ GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{\pi^+}>200$MeV/c, $p_{\mu^-}>200$MeV/c, $\cos \theta_{\pi^+}>0.3$ and $\cos \theta_{\mu^-}>0.3$. The total flux integrated $\nu_\mu$ charged current single positive pion production cross section on water in the restricted phase-space is measured to be $\langle\sigma\rangle_\phi=4.25\pm0.48 (\mathrm{stat})\pm1.56 (\mathrm{syst})\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$. The total cross section is consistent with the NEUT prediction ($5.03\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$) and 2$\sigma$ lower than the GENIE prediction ($7.68\times10^{-40} \mathrm{cm}^{2}/\mathrm{nucleon}$). The differential cross sections are in good agreement with the NEUT generator. The GENIE simulation reproduces well the shapes of the distributions, but over-estimates the overall cross section normalization.

Prospects for detecting galactic sources of cosmic neutrinos with IceCube: An update

Air-Cherenkov telescopes have mapped the Galactic plane at TeV energies. Here we evaluate the prospects for detecting the neutrino emission from sources in the Galactic plane assuming that the highest energy photons originate from the decay of pions, which yields a straightforward prediction for the neutrino flux from the decay of the associated production of charged pions. Four promising sources are identified based on having a large flux and a flat spectrum. We subsequently evaluate the probability of their identification above the atmospheric neutrino background in IceCube data as a function of time. We show that observing them over the twenty-year lifetime of the instrumentation is likely, and that some should be observable at the 3 σ level with six years of data. In the absence of positive results, we derive constraints on the spectral index and cut-off energy of the sources, assuming a hadronic acceleration mechanism.

Double-spin asymmetryALTcosϕSin semi-inclusive DIS at CLAS12 and EIC within the collinear framework

We study the longitudinal-transverse double-spin asymmetry with a $\cos\phi_S$ modulation in semi-inclusive deep inelastic scattering for charged and neutral pions production. We consider the particular case in which the transverse momentum of the final state hadron is integrated out. The corresponding asymmetry may be contributed by two parts: one is the convolution of the twist-3 distribution function $g_{T}(x)$ and the unpolarized fragmentation function $D_1(z)$, the other is related to the coupling of the transversity distribution function $h_1(x)$ and the collinear twist-3 fragmentation function $\tilde{E}(z)$. We take into account both contributions to predict the $\cos\phi_S$ asymmetry at the kinematics of CLAS12 and a future Electron Ion Collider. We find that the asymmetry of pion production at CLAS12 is sizable, and $\tilde{E}(z)$ can play an important role in the asymmetry in the large-$z$ region.

Rapidity Distribution of Charged Pions From Pb+Pb and Au+Au Central Collisions

Rapidity distributions for charged pions produced from central collisions Pb+Pb and Au+Au at (b ≤ 3.4 fm.) in range of energy 2 GeV up to  = 200 GeV are investigated. The experimental results are studied  in terms of the Ultra-relativistic Quantum Molecular Dynamic Model Ur-QMD. In general, the model can give suitable predictions of rapidity distributions for production of charged pions from interactions with energies below 160 A GeV. This model is supported the assumption that the onset of de-confinement is located at low energies. It treats the initial nucleon-nucleon interactions within a string-hadronic framework. In addition, it includes effects such as string-string interactions and hadronic re-scattering that expected to be relevant in A+A collisions. There is a kind of similarity for mechanism responsible for production of the two charge states of pions and it can extended to other hadrons. Ultra-relativistic quantum molecular dynamic model give good description on energy dependence for charged pion productions and points of maximum rapidity.Â

Jet quenching from QCD evolution

Recent advances in soft-collinear effective theory with Glauber gluons have led to the development of a new method that gives a unified description of inclusive hadron production in reactions with nucleons and heavy nuclei. We show how this approach, based on the generalization of the DGLAP evolution equations to include final-state medium-induced parton showers, can be combined with initial-state effects for applications to jet quenching phenomenology. We demonstrate that the traditional parton energy loss calculations can be regarded as a special soft-gluon emission limit of the general QCD evolution framework. We present phenomenological comparison of the SCET$_{\rm G}$-based results on the suppression of inclusive charged hadron and neutral pion production in $\sqrt{s_{NN}}=2.76$ TeV lead-lead collisions at the Large Hadron Collider to experimental data. We also show theoretical predictions for the upcoming $\sqrt{s_{NN}} \simeq 5.1$ TeV Pb+Pb run at the LHC.

Predicting thesinϕStransverse single-spin asymmetry of pion production at an electron ion collider

We study the transverse single-spin asymmetry with a $\sin\phi_S$ modulation in semi-inclusive deep inelastic scattering. Particularly, we consider the case in which the transverse momentum of the final state hadron is integrated out. Thus, the asymmetry is merely contributed by the coupling of the transversity distribution function $h_1(x)$ and the twist-3 collinear fragmentation function $\tilde{H}(z)$. Using the available parametrization of $h_1(x)$ from SIDIS data and the recent extracted result for $\tilde{H}(z)$, we predict the $\sin\phi_S$ asymmetry for charged and neutral pion production at an Electron Ion Collider. We find that the asymmetry is sizable and could be measured. We also study the impact of the leading-order QCD evolution effect and find that it affects the $\sin\phi_S$ asymmetry at EIC considerably.

Coherent pion production in neutrino-nucleus scattering

In this article, we study the coherent pion production in neutrino-nucleus interaction in the resonance region using the formalism based on partially conserved axial current (PCAC) theorem which relates the neutrino-nucleus cross section to the pion-nucleus elastic cross section. The pion nucleus elastic cross section is calculated using the Glauber model in terms of pion-nucleon cross sections obtained by parameterizing the experimental data. We calculate the differential and integrated cross sections for charged current coherent pion production in neutrino carbon scattering. The results of integrated cross section calculations are compared with the measured data. Predictions for the differential and integrated cross sections for coherent pion productions in neutrino iron scattering using above formalism are also made.

Multiplicity dependence of charged pion, kaon, and (anti)proton production at large transverse momentum in p–Pb collisions at sNN=5.02 TeV

The production of charged pions, kaons and (anti)protons has been measured at mid-rapidity ($-0.5 < y < 0$) in p-Pb collisions at $\sqrt{s_{\rm NN}}=5.02$ TeV using the ALICE detector at the LHC. Exploiting particle identification capabilities at high transverse momentum ($p_{\rm T}$), the previously published $p_{\rm T}$ spectra have been extended to include measurements up to 20 GeV/$c$ for seven event multiplicity classes. The $p_{\rm T}$ spectra for pp collisions at $\sqrt{s}=7$ TeV, needed to interpolate a pp reference spectrum, have also been extended up to 20 GeV/$c$ to measure the nuclear modification factor ($R_{\rm pPb}$) in non-single diffractive p-Pb collisions. At intermediate transverse momentum ($2 < p_{\rm T} < 10$\,GeV/$c$) the proton-to-pion ratio increases with multiplicity in p-Pb collisions, a similar effect is not present in the kaon-to-pion ratio. The $p_{\rm T}$ dependent structure of such increase is qualitatively similar to those observed in pp and heavy-ion collisions. At high $p_{\rm T}$ ($>10$ GeV/$c$), the particle ratios are consistent with those reported for pp and Pb-Pb collisions at the LHC energies. At intermediate $p_{\rm T}$ the (anti)proton $R_{\rm pPb}$ shows a Cronin-like enhancement, while pions and kaons show little or no nuclear modification. At high $p_{\rm T}$ the charged pion, kaon and (anti)proton $R_{\rm pPb}$ are consistent with unity within statistical and systematic uncertainties.

Photoproduction of vector mesons: from ultraperipheral to semi-central heavy ion collisions

We discuss nuclear cross sections for $AA \to AAV$ and $AA \to AAVV$ reactions with one or two vector mesons in the final state. Our analysis is done in the impact parameter space equivalent photon approximation. This approach allows to consider the above processes taking into account distance between colliding nuclei. We consider both ultraperipheral and semi-central collisions. We are a first group which undertook a study of single $J/\psi$ photoproduction for different centrality bins. We show that one can describe new ALICE experimental data by including geometrical effects of collisions in the flux factor. Next, total and differential cross section for double-scattering mechanism in the exclusive $AA \to AAVV$ reaction in ultrarelativistic ultraperipheral heavy ion collisions is presented. In this context we consider double photoproduction and photon-photon processes. Simultaneously, we get very good agreement of our results with STAR (RHIC), CMS and ALICE (LHC) experimental data for single $\rho^0$ and $J/\psi$ vector meson production. A comparison of our predictions for exclusive four charged pions production is also presented.

Single-Spin Asymmetries AULsinϕh in Semi-Inclusive Pions Production

The single-spin asymmetry [Formula: see text] of charged and neutral pion production in semi-inclusive deep-inelastic scattering on longitudinally polarized nucleon targets is studied. We particularly consider the effects of the twist-3 transverse-momentum dependent distribution functions [Formula: see text] and [Formula: see text], which are calculated in two different spectator-diquark models. We estimate the asymmetry for [Formula: see text], [Formula: see text] and [Formula: see text] produced off the proton target at HERMES and compare the results with the HERMES measurements. We also predict the same asymmetric moment for different pions at the kinematics of CLAS 5.5 GeV on a proton target, as well as at COMPASS on a deuteron target for comparison.

Polarimetry with inclusive charged pions at U-70 accelerator of IHEP

A feasibility of the proton beam polarimetry based on exploiting the observed large single-spin asymmetry AN in inclusive charged pion production is evaluated for the SPASCHARM experiment at IHEP, Protvino, Russia. It is shown that, for a few hours of beam exposition time, the beam polarization could be measured at the statistical errors of ∼3-5%. The inclusive pion polarimetry at SPASCHARM does not require construction of a special polarimeter. The polarimetry will be carried out entirely by the main SPASCHARM spectrometer simultaneously with physics data taking.

Charged pion production inνμinteractions on hydrocarbon at⟨Eν⟩=4.0 GeV

Charged pion production via charged current $\nu_{\mu}$ interactions on plastic (CH) is studied using the MINERvA detector exposed to the NuMI wideband neutrino beam at Fermilab. Events with hadronic invariant mass W $<$ 1.4 GeV are selected to isolate single pion production, which is expected to occur primarily through the $\Delta(1232)$ resonance. Cross sections as functions of pion production angle and kinetic energy are reported and compared to predictions from different theoretical calculations and generator-based models, for neutrinos ranging in energy from 1.5 GeV to 10 GeV. The data are best described by calculations which include significant contributions from pion intranuclear rescattering. These measurements constrain the primary interaction rate and the role of final state interactions in pion production, both of which need to be well understood by neutrino oscillation experiments.