Replica Target Research Articles

Measurements of pi ^pm , K^pm and proton double differential yields from the surface of the T2K replica target for incoming 31\xa0GeV/c protons with the NA61/SHINE spectrometer at the CERN SPS

Measurements of the pi ^pm , K^pm , and proton double differential yields emitted from the surface of the 90-hbox {cm}-long carbon target (T2K replica) were performed for the incoming 31,hbox {GeV}!/!c protons with the NA61/SHINE spectrometer at the CERN SPS using data collected during 2010 run. The double differential pi ^pm yields were measured with increased precision compared to the previously published NA61/SHINE results, while the K^pm and proton yields were obtained for the first time. A strategy for dealing with the dependence of the results on the incoming proton beam profile is proposed. The purpose of these measurements is to reduce significantly the (anti)neutrino flux uncertainty in the T2K long-baseline neutrino experiment by constraining the production of (anti)neutrino ancestors coming from the T2K target.

Towards T2K neutrino flux predictions using the replica target measurements by NA61/SHINE

The precise knowledge of the neutrino flux composition and kinematics is one of the biggest challenges of long-baseline experiments such as T2K. Neutrinos are made by the in-flight decay of unstable hadrons produced by the interactions of 31GeV/c protons in a long graphite target. Mostly π+ (π−) are created, leading to the enhanced flux. As kaons and muons are also produced, an irreducible background of electron (anti-)neutrino is also present. The main source of uncertainty in the flux prediction is driven by the lack of data on the proton-carbon interaction in this energy range. The measurements performed by the NA61/SHINE large-acceptance experiment at CERN are used by the T2K collaboration to improve the flux predictions. Two datasets have been taken: using a thin target to study the primary interaction, and a replica of the T2K target to account for the re-interactions. The recently released differential multiplicity distributions of π± along the replica target measured in NA61/SHINE will be presented. This dataset is now in the process of being used by T2K to further tune the flux prediction as 90% of the neutrinos will be directly constrained.

Measurements of $$\pi ^\pm $$ π ± differential yields from the surface of the T2K replica target for incoming 31 GeV/c protons with the NA61/SHINE spectrometer at the CERN SPS

Measurements of particle emission from a replica of the T2K 90 cm-long carbon target were performed in the NA61/SHINE experiment at CERN SPS, using data collected during a high-statistics run in 2009. An efficient use of the long-target measurements for neutrino flux predictions in T2K requires dedicated reconstruction and analysis techniques. Fully-corrected differential yields of $\pi^\pm$-mesons from the surface of the T2K replica target for incoming 31 GeV/c protons are presented. A possible strategy to implement these results into the T2K neutrino beam predictions is discussed and the propagation of the uncertainties of these results to the final neutrino flux is performed.

Hadron production measurement from NA61/SHINE

An overview of the recent NA61/SHINE results on determination of charged hadron yields in proton-carbon interactions is presented. The results aim to improve predictions of the neutrino flux in the T2K experiment. The data were recorded using a secondary-proton beam of 31 GeV/c momentum from CERN SPS scattered off a graphite target. To determine the inclusive production cross-section for charged pions, kaons and protons the thin (0.04 λI) target was exploited. Results of this measurement are used in the T2K beam simulation program to reweight hadron yields in the primary interaction vertex and allow to constrain directly about 60% of the neutrino flux. At the same time, NA61/SHINE results obtained with the T2K replica target (1.9 λI) would allow to constrain up to 90% of the neutrinos, thus reducing significantly a model dependence of the neutrino beam prediction.The proposal to collect hadroproduction data on thin and NuMI (Neutrinos at the Main Injector in Fermilab) replica targets exposed to a 120 GeV/c proton beam is reviewed. These data will be used further in neutrino beam calculations for the MINERvA, MINOS(+) and LBNE experiments.

Pion emission from the T2K replica target: Method, results and application

The T2K long-baseline neutrino oscillation experiment in Japan needs precise predictions of the initial neutrino flux. The highest precision can be reached based on detailed measurements of hadron emission from the same target as used by T2K exposed to a proton beam of the same kinetic energy of 30GeV. The corresponding data were recorded in 2007–2010 by the NA61/SHINE experiment at the CERN SPS using a replica of the T2K graphite target. In this paper details of the experiment, data taking, data analysis method and results from the 2007 pilot run are presented. Furthermore, the application of the NA61/SHINE measurements to the predictions of the T2K initial neutrino flux is described and discussed.

The HARP experiment at the CERN PS

The HARP experiment at the CERN PS has collected data for hadroproduction measurements with a large set of targets, ranging from hydrogen to lead, in the momentum range 1.5 - 15 GeV/c. The performances of the apparatus, both the large angle detector and the forward spectrometer, are outlined. First results for a thin 5%λ aluminium K2K replica target with a 12.9 GeV/c proton beam are reported.