PoS(Nufact08)010 http://pos.sissa.it/ -scattering experiments: K2K, ν A. At the end, we summaries the future ν † ∗ [email protected] Speaker. for the K2K, Super-K, SciBooNE and T2K collaborations MiniBooNE, MINOS, SciBooNE, T2K and MINER Knowledge of neutrino interactions with ais nuclear recently target getting at more the and neutrino more energytrino important around oscillation as sub-GeV experiments. necessary A information study for ofwith accelerator neutrino based nucleus, interactions neu- and contains is rich physics usedWe of to review neutrinos the reveal recent the neutrino properties scattering oftions experiments neutrinos addressing with the a in physics nucleus. the of oscillation We neutrinomodeling list measurements. interac- of the the recent quasi-elastic unresolved scattering problems process inprocess. and neutrino the We interactions, present neutrino especially induced the signle recent pion status production and new results fromoutlook. the ∗ † Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. c

10th International Workshop on Neutrino Factories,June Super 30 beams - and July Beta 5 beams 2008 Valencia, Spain Tsuyoshi NAKAYA Experimental status of neutrino scattering physics and needed measurements Kyoto University E-mail: PoS(Nufact08)010 . µ is 3 ν 0 after π → e ν µ ν → µ ν process and to 0 production is the π Tsuyoshi NAKAYA 0 π ], the neutrino mass and , because the CC-1 oscillation is one of the which potentially suffers 1 0 e 0 π ν ) π + → µ ( µ + ν e → process where we miss the pion either p π ]. We know that the understanding of this 5 , ], attracts many attentions to provide the new 4 2 2 oscillation is compared with that of e ν → ] requests equal knowledge of neutrinos and anti-neutrino 7 µ ν ]. So, it is important to understand the NC-1 3 , 2 ]. 6 ) production by neutrino interactions is also the most important channel π and many recent experiments are focused on understanding of the CC-QE process. 2 Finally, the experimental data of anti-neutrino interactions around sub-GeV are not rich and The single pion (1 After the discovery of neutrino oscillations in atmospheric neutrinos [ The charged-current (CC) quasi-elastic (QE) scattering with a nuclear target is the primary carefully subtraction of theunderstood background with processes. the The same anti-neutrinoaddition, level as interactions an neutrino must anti-neutrino interactions beam be in althoughmake well- low the it energy background has has understanding lower somehow typically cross complicated. a sections. contamination Currently, of the In MiniBooND neutrinos, and which Sci- most interesting subjects in future experiments,background and in the neutral-current K2K (NC) and 1 T2Kmeasure [ the cross section itself andwith the momenta the of effects the final of produced nuclear medium. For a precise study of neutrino oscillation in the process is important to developWater Cherenkov a detector next [ generation proton decay experiment with a Megaton-size no data exists on the CC-QE processlations below in 1 the GeV. The accelerator future experiments CP [ violation study on neutrino oscil- interactions where the probability of mixing are intensively studied byatmospheric many neutrinos experiments and with accelerator solarcelerator neutrinos. neutrinos, neutrinos reactor is The anti-neutrinos, one study ofneutrinos, of the a neutrino most whole oscillation promising scheme with approachesmetry of the to in the reveal ac- neutrinos, the neutrino and unknown mixing properties toaccelerator and of neutrino provide the oscillation precise particle experiment, information and T2K on anti-particle [ the (CP) neutrino asym- mass. A next generation in neutrino interactions because itbackground is in a neutrino dominant process oscillation for experiments. sub-GeV neutrinos A and search it for is a severe oscillation channel, a dominant background is the CC-1 a dominant background by atmospheric neutrinos [ channel in neutrino interactions whichis must a be dominant well-understood process and for properlyin sub-GeV modeled experiments. neutrinos because and Although it is it oftendata looks used exists, like to a complicated reconstruct straight-forward phenomena the processSection are neutrino with energy involved a by nucleon treating of a which nuclear many target. It is explained in neutrino scattering experiments 1. Introduction information. At the sameneutrino time, oscillation we experiments recognize that requestwith the more a further accurate precision nuclear information studies target on intection. which interactions the is From of accelerator the the neutrinos target viewknowledge material point, of of neutrino recently, interactions massive many with neutrino attentions aaddress detectors are nuclear these target for drew at issues, to neutrino the several understand de- energy neutrino and aroundinteractions scattering sub-GeV. with improve In a experiments the order nuclear are to target. conducted The to neutrino scattering study experiments the are neutrino introduced in Section by nuclear effects orchannel by is the equally important detection to technique. search for a In proton-decay, addition to study neutrino oscillation, this PoS(Nufact08)010 π 03. The . 1 = A M Tsuyoshi NAKAYA distributions in K2K 2 ] and the measurement Q ]. Both NEUT and NU- 11 ]. Here, the MiniBooNE ] although the clear obser- [ because our observation is 10 2 12 13 [ c A / 2 M c / process is very limited and the clear 12 GeV π . 0 production [ 20 GeV . ± 0 π ]. Rein and Sehgal updated their models by 20 ± . 14 as an effective 1 23 . A = 3 1 M A = M was measured by many past experiments. The mean 011. It is very interesting to test the CC-QE modeling . collect anti-neutrino data and under analysis. A 0 e f f 3 A M ± M 019 ]. Recently the MiniBooNE collaboration finds the evidence of . 1 15 ]. It is interesting to check the consistency between the null K2K , the single pion production is the second dominant channel at the = , and the 1 A κ 16 with the error of a few percent. The observed M 2 . It looks natural that the similar effect could be observed in the CC-1 c / 2.1 production [ 0 π is 1.03 GeV ] and the MiniBooNE collaboration used the NUANCE [ 9 A , M 8 The CC-QE process is thought to be well described in the vector and axial-vector form Another interesting subject is the process of coherent pion production by neutrinos. The K2K As introduced in Section When modern neutrino oscillation experiments, K2K and MiniBooNE, started, it was found including the lepton mass effect [ experiments reported the null result of the CC coherent of MiniBooNE with a carbon target is not a scattering withsuffered a by nucleon, the but nuclear withPauli-suppression effect. a parameter, nuclear Furthermore, target. the Therefore, MiniBooNE the collaboration observation also might introduces be the channel as CC-QE. However, the existingextraction data of for signal the is CC-1 not as easy as for CCQE. Therefore, we have no conclusion yet. NC coherent proposed by the MiniBooNE collaboration by upcoming new experiments. 2.2 Single pion production sub-GeV neutrino energy. One interesting subjecteven is the again simpler the model form of factors CC-QEas of is this described claimed process in to because Section modify the axial form factor for the nuclear target and MiniBooNE tend to bemeasurements more of K2K energetic with than a the water MC target is model prediction with collaboration defines a new interpretation for vation was expected by the Rein and Sehgal model [ that our knowledge ofdata. neutrino For interactions the was simulation not oflibrary neutrino well [ interactions, satisfied the to K2K describe collaboration used the the experimental NEUT program 2. Puzzles value of neutrino scattering experiments BooNE experiments described in Section ANCE adopt the similarwhich theoretical simulator models is with better the tosively nuclear studied describe effects, the the and neutrino data. it interactions,match Both well is and K2K with found not the and some a MC MiniBooNE hints prediction. cleartering collaborations why and Here, guide inten- the the we single introduce experimental pion the data production. unforeseen do results not in the CC-QE scat- 2.1 Quasi-Elastic scattering factors which are expresseddata with of the electron dipole scattering formula. experiments.only The one The axial-vector parameter, vector form called form factor with factor the is dipole well formula known has by PoS(Nufact08)010 ), the > ν E < A experiments. ]. The observed ν Tsuyoshi NAKAYA 18 , 16 together by comparing with sev- 0 π production [ 0 π " events is shown as a guide to know roughly ν appearance is not severe to take matter of this e in the muon neutrino beam. Although the Mini- 4 ν e for the mean neutrino beam energy ( ν 1 events). The "# ν momentum distribution in NC-1 and the positive signal of NC coherent 0 π π , CH, Fe, Pb, C. In addition, several different detector technologies are used for 2 ]. 17 ]. This phenomena is only observed by the MiniBooNE experiment because Mini- O, CH 2 19 K2K is the first generation long-baseline neutrino oscillation experiments from KEK to Kamioka. Physics with neutrino scattering is conducted by using the detectors in neutrino oscillation Finally, another most important quantity is the momentum distribution of pions because it The last puzzle in neutrino interactions is the low energy elecron excess observed by Mini- momentum looks softer than the MC predictions, which may indicate that the treatment of the production [ 0 The K2K neutrino beam was producedenergy by of the 1.3 KEK GeV 12-GeV for Proton neutrinos. SynchrotronKamiokande. and K2K The had has K2K the the near mean near detector and systemsets far consisted detectors, of of and the 1 the fine-grained kiloton far detector detectors Waterthe Cherenkov is muon (SciFi, detector Super- range SciBar) and detector with (MRD). The the K2K electro-magnetic experiment calorimeter and the (EC) near and detectors are well described in the studies. 3.1 K2K detector type, the fiducial mass ofevents interacted the in detector, the and detector the (# targethow material many and events the are number occurred of inexperiments neutrino the cover the detector neutrino with energy the from a fulltargets: few running hundred H time MeV of up to the 30 experiment. GeV with Those various nuclear BooNE has the best sensitivity to identifying The experiments are summarized in Table experiments and a few dedicated neutrinodetectors scattering located experiments. close The to formerand case the is the neutrino the detector beam neutrino in source MiniBooNE. in The the latter K2K, case MINOS is and T2K the experiments SciBooNE and MINER BooNE collaboration intensively investigates the source of theidentified events, yet. the origin Although of the the impact excessbecause of is not this the background sensitivity to of T2K T2K wasbackground around concerned, by comparing it 0.4% with may in the be sensitivity marginal of MiniBooNE around 0.1 %. 3. Neutrino Scattering Experiments directly affects the background levelBooNE in measured neutrino the oscillation experiments. So far, K2K andnuclear Mini- effects is not good enough.tion of For the future pion momentum neutrino distributions oscillation bythe experiments, the background. the MC To simulations better improve are estima- the necessary to prediction,issues. accurately further predict experimental data are important to resolve the 2.3 Low energy electron excess BooNE [ neutrino scattering experiments result on CC coherent eral theoretical models. Recently, the SciBooNEπ collaboration looks for the signal of CC coherent π PoS(Nufact08)010 k k k M 100 M M 1 5 10 100 500 events ∼ A ]. ]. ]. ∼ ∼ k ν ∼ ∼ ∼ M # 12 21 24 50 , (as reference) 18 , O 2 13 events which , POT neutrino 2 higher by com- 11 2 20 ) Q , . Tsuyoshi NAKAYA 5 Fe 10 CH CH 000 tons with 1,520 Target Target ]. With an advantage , O, CH, Fe syst × 011. MiniBooNE de- Fe, Pb, C 2 1 ( . 6 16 0 . H ∼ 078 072 . . Fe, Pb, CH, H ± 0 0 + − is consistent with the former ) 019 A . %. Those new results are under fit 1 M ) ( = 50 10 3 15 production [ ] by using the SciBar detector [ 440 077 κ 33 10 0 ∼ ∼ . ∼ ± (ton) 23 π 0 ∼ 5 2 39 ± ( Fiducial mass 144 . ] by production is found to be slightly higher than 1 9 0 , POT (Protons-On-Target) with a neutrino beam = 8 π 5 A production [ 20 0 M π 10 × 6 . ] and the result of MiniBooNE with the carbon target [ FGD FGD FGD Detector 11 Oil Cherenkov ]. In addition, MiniBooNE find a deficit of low Summary of Neutrino Scattering Experiments Iron/Plastic sandwich 12 has the value of Water Cherenkov, FGD [ POT with an anti-neutrino beam. By using 5 A 2 20 c M / > 3 7 7 7 10 ] and the CC single . . . . 30 30 Table 1: ν 1 0 0 0 × E 22 ∼ ∼ ∼ ∼ ∼ ∼ 5 (GeV) 2 2 . < 20 GeV ]. The K2K near detectors located inside KEK have rich data on neutrino scatter- events and find an evidence of NC coherent . 0 0 20 π ± A ν 23 ]. MiniBooNE has very high statistics data of neutrino interactions with 450 ton fiducial . 1 25 ]. The MiniBooNE detector is a mineral oil Cherenkov detector of = MiniBooNE is a short-baseline neutrino oscillation experiment to test the evidence of neu- MINOS is the long-baseline neutrino oscillation experiment to confirm the neutrino oscillation 19 SciBooNE MINER T2K (Near) K2K (Near) MiniBooNE e f f A MINOS (Near) trino transition claimed by LSND.nal MiniBooNE [ reported the result not supporting the LSND sig- and to measure neutrino oscillation parameterstor) precisely. neutrino The beam NuMI for (Neutrinos MINOS at has the the Main tunability Injec- for the neutrino energy and flux, and is typically The result on the crossthe section prediction of by models the implemented CC in single NEUTpreparation [ for publication. 3.2 MiniBooNE PMTs [ configuration and 2 beam data, MiniBooNE measured the CC-QEM scattering on Carbon with an effective axial mass of of high statistics data, the MiniBooNE collaborationanti-neutrino extends interactions. various physics analysis including the 3.3 MINOS mass. MiniBooNE collected data of 6 ing, and provided several importantIn results addition on to the the published neutrino results, scatteringwith K2K a physics recently carbon [ shows target the [ preliminaryThe results results on on the the CC-QE CC-QE is accounted by introducing the Pauli-suppression parameter, the reference [ neutrino scattering experiments paring with the mean value of old experiments. The new value of tected 28,600 result of K2K with the water target [ PoS(Nufact08)010 2 POT. 1cm ] and 20 × 24 10 process and -DIS events × ν π ]. The SciBooNE Tsuyoshi NAKAYA 28 , events at 3 27 + POT with an anti-neutrino π 20 10 process, and NC elastic process 0 × π 54 . -DIS events and 300,000 ν ]. The analysis of anti-neutrino beam data 17 process, NC-1 6 π events and 2,700 CC coherent POT, 2,600,000 0 20 π 10 × POT. The MINOS front detector (FD) is located 1 km away from the target 20 ]. The SciBooNE beam is FNAL-BNB and the detector located 100 m down- 10 26 × POT with a neutrino beam configuration and 1 POT, 1,700 NC coherent 20 20 10 POT. The MINOS collaboration can study the CCQE scattering, a low energy neutrino 10 × 20 × T2K is the next generation long-baseline neutrino oscillation experiments from Tokai to Kamioka. SciBooNE is a dedicated neutrino scattering experiment to study neutrino interactions physics 99 4 GeV and with the flux tail extending up to 30 GeV. The MINOS experiments collected data 4 10 . . detector (P0D), two fine-grained scintillator vertex detectors (FGD) with a water target, three ∼ × 0 with neutrino beam data. Thethe SciBooNE preliminary collaboration result search was for presented the at ICHEP2008 CC-coherent [ collaboration studies the CC-QE process, CC-1 large-volume TPCs sitting side byrange side detector of (SMRD). FGDs, The Electron-Calorimeter uniqueness of (ECAL), T2K and ND280-offaxis a is side the muon finer granuality of 1 The T2K neutrino beam willof be 30 produced GeV. The by narrow-band the neutrinooff-axis J-PARC beam technique MR with with accelerator the with the mean the off-axis energyand initial of angle the 0.7 energy of near GeV 2.5 detector is degree. consistsneutrino produced of detector by The (ND280-offaxis) so-called the located far neutrino 280 detector beam mlar downstream is monitor from type Super-Kamiokande, (named sandwich the detector target. INGRID) of INGRID and iron is off-axis andton a plastic each. modu- scintillators. The INGRID primary consists purpose of ofthe 16 INGRID modules neutrino with is beam. 10 not to For study thisimportant the for purpose, neutrino INGRID. experimental interactions, The inputs ND280-offaxis but is to of thethe monitor the fine UA1 neutrino grained dipole tracking magnet interactions detectors with with mounted the iron inside magneticπ of field is of 0.2 T. The ND280-offaxis consists of a dedicated at 7 stream from the proton target. The SciBooNE detector isbeam. the The first K2K results SciBar from SciBooNE detector were presented [ in this conference [ is on-going and is expected to be available in 2009. 3.5 T2K scintillators, momentum measurement with thefore, magnetic it field is expected and to fine-segmented provide the ECAL.operation. most There- precise The information first on neutrino T2K interactions beam once is it starts expected the to be shot in April 2009. The installation of ND280 is of more than 4 at FNAL-BNB [ neutrino scattering experiments operated with the low3 energy configuration which produces the neutrinos at the peak energy of 3.4 SciBooNE Electron-Catcher (EC) together with the newly builtof muon range 0 detector. SciBooNE collected data and has the total mass ofscintillators 1 kilo-ton. with The the detector magnetic is field athe of sandwich MINOS type 1.2 FD of T. magnetized collected Because iron 5,500,000 of and3 CC plastic the neutrino high interactions intensity in NuMI theflux neutrino fiducial extraction, beam, mass an of inclusive 33 CC tonscoherent cross-section pion with shape, production DIS although they and have structure nothave get function, 800,000 the and CC-QE preliminary CC results events yet. and at MINOS 3 NC expects to PoS(Nufact08)010 A ν POT. 20 10 × Tsuyoshi NAKAYA , 3319 (1998) 81 , 1562 (1998) 81 , 181801 (2006) [arXiv:hep-ex/0603004]. 14 Million neutrino interactions which 96 ∼ dependence of neutrino interactions. The A 7 region, the structure functions, the coherent pion 2 Q . They plan to run for four years with the NuMI low energy POT and the medium energy configuration for 12 Pb 20 A detector is a finely segmented, fully active, scintillator tracking ν 10 , and × Fe , [K2K Collaboration], Phys. Rev. Lett. [Super-Kamiokande Collaboration], Phys. Rev. Lett. C , [Super-Kamiokande Collaboration], Phys. Rev. Lett. et al. et al. [The T2K Collaboration], arXiv:hep-ex/0106019. He et al. A A is a high precision neutrino scattering experiment at the FNAL Main Injector. The ν ν et al. A will use the NuMI neutrino beam. The detector will locate in front of the MINOS ν [arXiv:hep-ex/9807003]. [arXiv:hep-ex/9806014]. MINER The experimental aspects of neutrino scattering physics are reviewed in this paper. Although The author would like to acknowledge support by Ministry of Education, Culture, Sports, [2] Y. Itow [3] S. Yamamoto [4] M. Shiozawa [1] Y. Fukuda neutrino scattering experiments scheduled in summer 2009 and datawe taking will expect start more around rich the data end on of neutrino 2009. interactions So, for in a3.6 the precision near neutrino MINER future, oscillation experiment. MINER front detector. The MINER chamber, surrounded by Electro-magnetic and Hadron calorimeters. The uniqueness of MINER is a wide variety of nuclear targets to measure the target nuclei are beam configuration for 4 the neutrino scattering physics areresolve getting the current more situation and of more poor understandingaction important, and processes there no with perfect a is modeling nuclear no of target. many special Itthe neutrino is virtue quality inter- a to of only way experimental to data. settleimprove the Since puzzles the several one modern by sensitivity one experiments by of are improving neutrino attacking neutrino scattering these oscillations, physics puzzles in to we the near are future. looking forward to the5. breakthrough Acknowledgment of Science and Technology in Japan (MEXT)with and the Japan Grant-in-Aid Society for for Scientific Research the A PromotionResearch 19204026, of Young on Scientists Science Priority S (JSPS) 20674004, Areas Scientific "New Developments"The of Next Flavor Generation Physics", of Physics, and Spun the from global Universality COE and program Emergence". References With a typical beam exposure,are it used is to study expected the to CC-QEresonance collect process, dominance the resonance to meson DIS, production,production the the and transition DIS region the low of charm the andand strange commissioning production. in 2009, The and experiment to is start taking planed data to in finish 2010. installation 4. Summary and Outlook PoS(Nufact08)010 , June , in Tsuyoshi NAKAYA , 231801 (2007) , in proceedings of 98 , 032301 (2008) . , 41 (2008) 100 664 , 252301 (2005) [arXiv:hep-ex/0506008]. , 255 (2005) [arXiv:hep-ex/0408134]. 95 . , 032003 (2008) [arXiv:0805.0186 78 619 , 072003 (2006) [arXiv:hep-ex/0606032]. , 174 (2007). 74 , 032003 (2008) [arXiv:0801.0182 [hep-ex]]. , 052002 (2006) [arXiv:hep-ex/0603034]. 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