Message-Id: <6.1.0.6.2.20041217224709.0292f8f0@pop.scphys.kyoto-u.ac.jp> Date: Fri, 17 Dec 2004 23:13:53 +0900 From: NAKAYA Tsuyoshi <nakaya@scphys.kyoto-u.ac.jp> Subject: Re: Possible K2K anti-neutrino run in 2005 Dear John and K2K collaborators, > >While in principle anti-neutrino running is a great idea, my reaction is >that it is impractical and perhaps a waste of resources due to low rates. >Two months of data will amount to how many events? > >It is my fault for not following the discussions in which you all have >doubtless discussed this issue. Can someone point me towards a report >whee this is justified? > I will attach the part of the minutes of the last K2K conveners meeting. In addition, I list how many events are expected with anti-neutrino run at the end of this e-mail. By the way, please note that we have still several hurdles to clear to get the approval and we have many severe boundary conditions, too. Regards, T. Nakaya +++ A part of the minutes of K2K conveners meeting on Dec. 15th, +++ > >********************************************************************** >Date & Time : 12/15 (Wed) [~8:50]9:00-11:00 >Place; Kamioka-Kashiwa-KEK-Kyoto-Tohoku-Hiroshima-USA-EU-......... >Type; IP conference (KEK MCU with ID=24346 > KEK person: Please make a reservation). >********************************************************************** > The presentation files are http://neutrino.kek.jp/internal/conveners/meeting/041215/ > >======== The agenda is ============ > >1. K2K run plan in 2005 10 min. K. Nishikawa http://neutrino.kek.jp/internal/conveners/meeting/041215/k2k2005.pdf The horn trouble in November 2004 is reported. The K2K run plan in 2005 is proposed with anti-neutrinos for two months to measure the NC coherent pi^0 production. All conveners attending the meeting agree with the proposal. > 1.1 K2K anti-neutrino beam 10 min. K. Hiraide http://neutrino.kek.jp/internal/conveners/meeting/041215/anti-nu_hiraide.pdf The anti-neutrino beam configuration and the expected beam flux are presented. The new first horn is installed downstream of the current second horn, and delivers the 40% neutrino flux relative to the original K2K dual-horn system. The neutrino flux in the anti-neutrino beam is as low as 5%. > 1.2 Physics sensitivity 10 min. Y. Hayato http://neutrino.kek.jp/internal/conveners/meeting/041215/anti-nu_hayato.ppt With the anti-neutrino beam for two month data taking, we search for the NC coherent pi^0 production. At the K2K meeting at Stony Brook, the SciBar group presented no CC coherent pi production in K2K, which indicates the measured cross section is less than 25% of the Rein and Sehgal model prediction. In the K2K extension, we search for the NC coherent pi^0 production in 1KT as well as a search for the anti-neutrino CC coherent pi production in SciBar. In the region of cos_theta_beam>0.6, we expect 13.8 coherent pi^0 events over 17.4 background pi^0 events with one month data of 5E18 POT in the 50 ton fiducial volume of 1KT. In SciBar, we expect 3.5 coherent pi^+ events over 2 background events with 5E18 POT (1 month). So we will have the conclusive result on the coherent pi production in the K2K beam energy. > 1.3 Discussion 10 min. all There is a question what shall we do to make the proposal approved. Basically, we just wait for the KEK decision. ================= Anti-neutrino statistics ===================== Assumption: two month run (1E19 POT) [1] SciBar; 10 ton fiducial volume; Total; ~700 CC CCQE 257 CC1pi 130 CC-coherent pi 32 CC-DIS 69 NC Elastic 103 1pi(charged) 26 1pi^0 42 coherent 16 other 26 * Note: The SciBar efficiency is around 70%. So we will observe ~500 events. [2] 1KT, 50 ton fiducial volume Total; ~3400 CC CCQE 1285 CC1pi 626 CC-coherent pi 122 CC-DIS 340 NC Elastic 504 1pi(charged) 134 1pi^0 203 coherent 66 other 121 [3] The number of reconstructed pi^0 in 1KT Total; ~130 NC resonance 57 coherent 33.2 DIS 29 CC 12 * Note, if we have selected the forward region, the coherent pi^0/all pi^0 ratio is 45%. by TN
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