K2k-I & K2k-Ii K2k-I & K2k-Ii
120 Annual Report 2005
alter AN and its effect would depend on the ratio r5 of flip is also shown. The fitted r5 is compatible, at about the single spin-flip amplitude to nonflip amplitudes one V level, with the hypothesis of no hadronic spin (see Ref. [4] for definitions). flip. 0.08 2
1.5 0.07 σ = 51.6 mb 3 σ
tot 5 2 σ ρ = 0.13 1
0.06 Im r 1σ b = 16.3 (GeV/c)-2 0.5 0.05 0
N 0.04 A -0.5
0.03 -1
-1.5 0.02
-2 r5 fitted 0.01 no hadronic spin flip -2.5 0 0 0.005 0.01 0.015 0.02 0.025 0.03 0.035 0.04 -3 -0.2 -0.15 -0.1 -0.05 -0 0.05 0.1 0.15 2 -t (GeV/c) Re r5 Fig. 1 The single spin analyzing power AN for three t intervals. Fig. 2 Fitted values of r5 (full circle) with contours corresponding Vertical error bars show statistical errors. The solid curve to the different confidence levels. The point corresponding to non corresponds to theoretical calculations without hadronic spin-flip hadronic spin-flip (triangle) is also shown. and the dashed one represents the r5 fit. [1] S.Bültmann et al., Phys. Lett. B 579 (2004) The values of AN obtained in this experiment and their statistical errors are shown in Fig. 1 for the three 245-250 t-intervals. The solid curve in Fig. 2 corresponds to [2] S.Bültmann et al., Nucl. Instr. Meth. A535 (2004) the calculation without hadronic spin-flip. The dashed 415-420 line represents the curve resulting from the fit with Re [3] S.Bültmann et al., nucl-ex/0507030 (2005) accepted for Phys. Lett. B r5 and Im r5 being the fit parameters [3]. The fitted [4] N.H. Buttimore et al., Phys. Rev. D59 (1999) values of Re r5 and Im r5 are shown in Fig. 2 together with contours for 1V , 2V and 3V confidence levels. In 114010 addition, the point corresponding to no hadronic spin-
6.14 Neutrino Experiments by D.Kieá czewska, T.Kozá owski, P.Mijakowski, P.Przewá ocki, E.Rondio, J.Stepaniak, M.Szeptycka, and J.Zalipska
-1 K2K-I & K2K-II Studies of neutrino interactions
] 10 2
eV In K2K – from KEK to Kamioka - experiment the [ 2
m interactions of neutrino beam from the KEK ∆ accelerator were observed in “near” detectors (on the accelerator side) and in Super-Kamiokande (“far” -2 detector, 293 km from the accelerator). 10 Neutrino oscillations have been studied using data collected by the K2K collaboration, in the Super- Kamiokande detector. This first long-baseline experiment found an evidence for the muon neutrino -3 10 disappearance [1], consistent with the atmospheric neutrino oscillations discovered in 1998 by the Super- K2K Kamiokande collaboration (Fig. 1). SK Zenith angle analysis The complete data obtained during 4 years of the K2K experiment have been used to search for electron -4 SK L/E analysis 10 neutrino appearance in the Super-Kamiokande 0 0.2 0.4 0.6 0.80. 1 detector. This is a subject of the PhD thesis by sin2(2θ) Fig. 1 J. Zalipska. DEPARTMENT OF HIGH ENERGY PHYSICS 121
T2K- from Tokai to Kamioka – is the next recoils resulting from elastic scattering of dark matter generation long baseline (295 km) neutrino oscillation particles. It will be located in the Canfranc experiment. Liquid argon TPC would be built as one underground laboratory in Spain. This work is done of the near detectors. As a preparation for future within ArDM collaboration led by A. Rubbia (ETH, studies of oscillation parameters in T2K experiment Zurich). A PhD student, P. Mijakowski studies the we participate in simulations of neutrino interactions background coming from the neutron interactions. in Ar. This is a subject of a PhD thesis by P. Przewá ocki.
ICARUS experiment: The R&D studies are [1] Evidence for Q P oscillation in an accelearator- performed using cosmic ray test data collected in the based experiment, Phys. Rev. Lett. 94 (2005) T-300 liquid argon TPC. To study the detector 081802 performance a sample of 250 S 0 decays was [2] Measurement of single p0 production in neutral reconstructed. The T-600 detector is already located in current n interactions with water by a 1.3 GeV the underground Gran Sasso laboratory. We wide band Q P beam, The K2K Collaboration: participate in the tests of electronics and in the design S.Nakayama et al., Phys. Lett. B619 (2005) 255 of triggering system. [3] Search for coherent charged pion production in Search for Dark Matter: We are involved in R&D neutrino-carbon interactions, The K2K studies for a search of dark matter using liquid argon Collaboration: M.Hasegawa et al., hep- detector. The detector is designed to observe nuclear ex/0506008, submitted to Phys. Rev. Lett.
6.15 Experiment „S of the Sky”*) by M.Górski, K.Nawrocki, M.Sokoá owski and G.Wrochna
The „S of the Sky” experiment [1] is designed to the year. The cameras are driven by a robotic mount, search for short optical flashes in the sky. The main which can move them to any point in the sky in < 1 motivation is to look for optical counterparts of min. Gamma Ray Bursts (GRB) [2]. GRBs are 0.1-100 s short pulses of gamma rays emitted by extragalactic sources. Intensity of the burst is often higher than the total background from all other gamma ray sources in the sky. So far, phenomena responsible for GRB have not been unambiguously identified. There are hints that certain type of supernovae explosions could be the source of bursts energy. Among other hypotheses are neutron star collisions leading to black hole creation or quark star collapse. In order to proceed with understanding the physics of GRB one Fig. 1 Installation at Las Campanas. needs to observe them also in wavelengths different During the operation from July 2004 till July 2005 from gamma rays [3]. the satellites observed 89 gamma ray bursts with The „S of the Sky” project is an attempt to apply known positions. Most of them happened during the experimental techniques of particle physics for day or below the horizon. Only 2 occurred within ”S detection of cosmic optical flashes. The apparatus of the Sky” field of view: GRB040825A and 050412. which is currently under construction is designed to In several other cases the system has moved to the cover 2 steradians of the sky. It consists of two sets of target shortly after the alert. No new optical sources 16 camera lenses of focal length 85mm. Lenses are have been found. Limits have been given and attached to a CCD camera with 2000×2000 pixels. published through GCN [4] for the cases, when ”S of Most of the analysis is performed in real time (on- the Sky” was faster than others: GRB040916B, line). Multilevel trigger system searches 60MB/s data 041217, 050123, 050326, and 050607. stream for optical flashes of 12-14 magnitudo and During this period, over 1 000 000 images have duration of the order of 10 s and longer. been taken. 103 optical flashes of unknown origin A prototype system with two cameras covering have been detected. They have not been confirmed by 30°×30° has been built and installed at Las Campanas other observations and one cannot exclude, that they Observatory (LCO) in Chile to profit from high are caused by sunlight reflexes from artificial altitude, clean atmosphere and clear sky over most of satellites.