104 Annual Report 2001 the final stale were preformed. Tests of charged 21 K.Kurck. A.Korzenev. K.Kowalik, A.Mielech, hadrons and scattered muon reconstruction wvith [lhe E.Rondio, R.Windmoldcrs. ,An algorithm for data were done. track reconstruction in the large angle spectrometer of the COMPASS experiment', 11] K.Kowalik. E.Rondio. R.Sulej. K.Zaremba, submitted to NIM A ..Selection of Photon Gluon Fusion Events in [3] M.Moinester, O.A.Grajek, E.Piasetzki, DIS". Acta Phys. Pol. B32(2001 A.Sandacz. .Color transparency via coherent exclusive rho production", Nucl. Phys. B (Proceedings Suppl.) 105 (2002)

6.17 Experiment PP2PP at RHIC PLO2OI865 by A.Sandacz

The experiment PP2PP [1] at RHIC studies elastic possible exchanges in elastic scattering, for inst.-nce of proton-proton scattering in a wide. mostly unexplored the three gluon exchange (odderon). domain of energy and momentum transfer: 50 < /; < The first data taking with colliding proton beams 500 GeV and 4 10- It |<1.3 GcV' T at RHIC took place during a five week period in measurements of the total cross section. the i-al part 2001/2002. Each proton beam had an energy of 100 of the elastic forward scattering amplitude, the slope GcV and the transverse polarization of about 15 c7,,. of the forward diffraction peak and of the differential The experimental setup lor this run is shown here. cross section in the region of the interference dip are The scattered protons, which mostly remain ins de the foreseen for different beam cnergies. In addition, beam pipes. are detected by the Roman pot detectors polarized proton beams offer the exciting opportunity (RP-2 RP2'). The Roman pots are equipped with the for comprehensive studies of spin effects in the total micro-strip silicon detectors and are connected to the and elastic cross sections. beam pipes with ultra high vacuum bellows. It allows These studies will elucidate the features of the to imove detectors as close to the beams as possible (- pomeron, which remains a m'stery forty years after it 15 nmm). The photograph shows a location in the beam was introduced. They will also clarify the role ofother tunnel, wvhe-e two stations of Roman pots are mounted on one of the RHIC beam pipes.

Inelastic Detectors DO DO_ ------DXa X - - L

RP2' RP2

-100. m -50. m 0. / 50. m 100. m

''~~~ DEPARTMENT OF HIGH ENERGY PHYSICS 105

In 2001, in addition to participation in the tests of and the slope of the forward elastic peak at the highest the apparatus and in the data taking, the main energy, which is presently available for the proton- responsibilities of the Polish members of PP2PP from proton scattering IFJ and IPJ were related to the development of the software. Specifically, they had to provide the event l W.Guryn etal.,(PP2PPCollaboration), displays and to develop algorithms for monitoring ,,Experiment to Measure Total Cross Sections, silicon detectors and various components of the Differential Cross Sections and Polarization triggers. Effects in pp Elastic Scattering at RHIC", RHIC The data collected during 2001/2002 run will Proposal PR7, Jan.1994; updated Sept. 1995 2 cover the range 0.005 < | t | < 0.02 GcV . It is expected that they will allow to determine the total cross section ff11lIIIW H ItIl PLO201 866 6.18 Neutrino Experiments by D.Kielczewska, T.Kozlowski, E.Rondio, J.Stepaniak, M.Szeptycka, J.Zalipska

Secrets of the mysterious neutrinos are one of the time 44 events have been observed in the 22.5 ktons most exciting questions recently appearing in physics. of SK, compared to 64 ± 7 interactions expected if no The interpretation of the observations from Super oscillations occurred and 41.5 ± 4.7 for v, oscillation Kamiokande experiment as neutrino oscillations parameters found with atmospheric neutrinos. The requires massive neutrinos. The fact that neutrinos distribution of parent neutrino energy, shown in Fig. I acquire mass is of great importance for the theory of for the sub-sample of single track muons observed in fundamental interactions between basic constituents of SK, is also consistent with these parameters but matter. Our activity is presently related with two further investigation of systematic errors is needed for experiments working in Japan (Super-Kamiokande quantitative conclusions. and K2K) as well as with the tests in European project The other part of activity of our group is related to with ICARUS detector. preparation and tests of the ICARUS experiment Measurements of neutrino masses and flavor planned in the Giran Sasso laboratory in Italy. Groups mixing in Super-Kamiokande (SK) are under way from Poland (Katowice, Krak6w, Warsaw, Wroclaw) using various neutrino sources and energies [1]. High decided to forn a single unified group and join this precision data on atmospheric neutrinos show that the project. In Warsaw group also participants from dominant mixings occur between active species. The Department of Nuclear Spectroscopy of our Institute analysis of these data carried out in the framework of and Institute of Experimental Physics of Warsaw three-flavor mixing yields the statistically significant University are involved. The research program of results, which confirm the almost maximal mixing v, ICARUS experiment is discussed in [3]. and Am2 of about 0.003-eV2 . Results of searches for T The ICARUS detector is a Time Projection neutrinos are consistent with this scenario. Chamber (TPC) filled with liquid argon. The EYF.C. 22.5kl-rmg g-like development of this technique started several years ago in Italy (first proposal was prepared in 1984). ICARUS is the largest TPC with liquid argon ever 1 l built. Therefore it should be carefully and systematically tested before putting it in operation in the experimental underground environment (Gran 10 Sasso). Such tests with cosmic ray muons were performed from the end of May until the 2'nd of August 2001 in Pavia with half of the full ICARUS module. The main goals were to reconstruct the very I t4 1 long tracks (of the order of 15-20 m), to check 0_ , . . t efficiency and uniformity in full active volume and to 91 2 3 calibrate the detector. 11W Fig. I Energy spectrum of neutrinos for subsumple of interactions The Warsaw group was responsible for part of the observed in K2K experiment in Super Kamiokande detector during external triggering system. It was prepared 12], first year of data taking (points) and histogram presenting spectrum mounted and supervised during technical run by expected without oscillations, members of our team. We also took part in shifts during test data taking. Now the data are analyzed arid The K2K experiment, which uses the KEK reconstruction program is being improved. Some accelerator as the neutrino source and the SK for their examples of events recorded during tests are presented detection, is sensitive to the oscillations observed in in Fig. 2. the atmospheric neutrinos. After one year of the run