Message-Id: <6.1.0.6.2.20041224235126.02d1d730@pop.scphys.kyoto-u.ac.jp> Date: Sat, 25 Dec 2004 00:05:43 +0900 From: NAKAYA Tsuyoshi <nakaya@scphys.kyoto-u.ac.jp> Subject: Minutes: K2K conv. meeting; 12/15 (Wed) 9:00-11:00 Dear K2K collaborators, This is the minutes of K2K conveners meeting on December 15th. At the conveners meeting, the spokesperson and conveners agreed with the anti-neutrino runs in 2005. However the proposal of anti-neutrino run is withdrawn NOT to disturb the T2K design and construction works. At this stage, it is not easy for us to explain the detailed reasons. We think that we may explain the reasons in future. Regards, T. Nakaya +++ 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. > >2. K2K-IIc run status (Oct-Nov 2004) > 2.1 Beam 5 min. Hasegawa/Sato http://neutrino.kek.jp/internal/conveners/meeting/041215/beam_summary_20041215.pdf The accumulated POT on this period is 3.78E18, and the POT for analysis is 3.12E18. The beam direction is stable within 1 mrad and the SSD-X sum over CT is by 5% lower than the average value of the previous run period. The problem of the SSD-X sum over CT will be investigated by the collaboration work with other neutrino detector groups. The GPS data is checked, and the fraction of bad spills for the analysis is only 0.03%. There is a comment that the GPS trouble with the double pulses was observed and should be fixed before the next K2K run. There is a question. Is the tiny vertical shift of the neutrino beam direction related to the change of the proton beam hit position at the target? The answer is NO. In addition, we will check how much is the change of the proton beam hit position at the target. > 2.2 1KT 5 min. Shiozawa/Miura http://neutrino.kek.jp/internal/conveners/meeting/041215/KT-20041215.ppt The 1KT data with the SK live is 2.87E18. The data set are processed with the new calibration constants. The event rate is (3.19+-0.04)xE-15/POT and consistent with the rate of Feb 2004 data, 3.22E-15/POT. Several distributions are checked and found to be consistent with the previous data. The small disagreements on the p_mu and cos(theta_mu) distributions are pointed. The forward three bins in the cos(theta_mu) distribution may show a change. Though it is difficult to judge the disagreement with the current statistics, the 1KT group will investigate it. > 2.3 SciFi 5 min. Sakuda http://neutrino.kek.jp/internal/conveners/meeting/041215/SciFi041214.ppt The SciFi group checks the RUN-IIc data set. The number of VETO-matched events is 1,656 without the goodspill selection. The number in RUN-IIb is 10,825 events. The RUN-IIc MC simulation is developed with the Al rod target. The vertex distributions are compared with the MC events. > 2.4 SciBar 5 min. Yokoyama http://neutrino.kek.jp/internal/conveners/meeting/041215/scibar_041215.pdf The SciBar group maintained the detector during the shutdown. The dead channel is now only one over 14,338 channels. The Electron Catcher (EC) readout cards are replaced by the new one with better performance. The gain and the photon yield are checked and confirmed to be stable. A trouble is that the EC High Voltage was off for the first one week of data taking just by a mistake. So, there are no EC data for 0.36E18 POT (12% of data in this period). SciBar accumulated 2.93E18 POT in this period, which corresponds to 17% of the RUN-IIb data. The event rate of SciBar-MRD3D sample is 427+-12 events/1E18POT/9.38ton which is consistent with 436+-5 events in the previous run period. > 2.5 MRD 5 min. Ishii http://neutrino.kek.jp/internal/conveners/meeting/041215/mrd041215.pdf The profile center, profile width, muon energy spectrum and muon angle distribution are checked to be stable. So the MRD data guarantee that the neutrino beam in RUN-IIc is not changed from the last run. The MRD event rate normalized by CT is slightly lower than the previous value, and the event rate normalized by SSD is a little bit higher. The MRD may see the same effect as the muon monitor. All detector groups will check the beam stability together. The number of SK events is expected to be 5.37. In addition, the careful E_nu stability check is performed based on E_mu and theta_mu variables. The stability of E_nu is checked bin by bin and confirmed to be much more stable than the flux uncertainty in the oscillation analysis. > 2.6 SK 10 min. Kaneyuki http://neutrino.kek.jp/internal/conveners/meeting/041215/SK_20041215.ppt SK accumulated 3.12 POT data in RUN-IIC. The GPS data quality is good. We have five SK events in the fiducial volume; three single ring muon events and two multi-ring events. The event rate, 1.60+-0.72 events/1E18 POT, is consistent with 1.23+-0.12 events/1E18 POT of Nov'99-Feb'02 data set. >3. Analysis Update > 3.1 SciBar coherent pi 10 min. Hasegawa http://neutrino.kek.jp/internal/conveners/meeting/041215/SB_coherentpi.ppt The final result of the CC coherent pi search is presented. There is no change in the analysis procedure as presented at the K2K meeting at Stony Brook. The new evaluation of some systematic errors are done and the analysis note is prepared. http://neutrino.kek.jp/internal/conveners/meeting/041215/k2kanalysisNote_cohe.ps.gz We have no evidence of the coherent pi production in K2K, and set the upper limit of sigma(coherent)/sigma(CC)<0.608E-2 at the 90% C.L.. The Rein and Sehgal model predicts the sigma(coherent)/sigma(CC)=2.67E-2. So the result is inconsistent with the Rein and Sehgal model. This result is also not consistent with the previous experimental results of NC coherent pi^0 production with an assumption of CC-coherent/NC-coherent=2. The paper committee will be formed, and the result will be published as a paper. > 3.2 SciFi MA 5 min. Gran http://neutrino.kek.jp/internal/conveners/meeting/041215/gran-convener20041215.pdf The final SciFi MA analysis is presented. One simple bug is found in the code, that the LG density correction was wrong. The new result is M_A=1.30+-0.12 in K2K-I, and 1.20+-0.18 in K2K-II. The combined result of K2K-I and K2K-II will be reported soon. The analysis note is already available for the collaboration. The paper committee will be formed, and the paper draft will be circulated for the collaboration by the end of January. > 3.3 1KT 10 min. Shiozawa http://neutrino.kek.jp/internal/conveners/meeting/041215/KT-20041215.ppt The goals of the 1KT group for the next K2K meeting are presented. The goals are [1] Confirmation or improvement of the fiducial volume error, [2] nu_e/nu_mu flux ratio and [3] the final result of proton decay background (mu+pi^0). They improved the detector calibration, and they are checking the effect now. They also check and improve the vertex fitter. The BONSAI is used as an initial fitter and the MS fit is under improvement. > 4. Discussion We will have the next conveners meeting in February to report the analysis status. written by TN
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