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Czech participation in the H1 experiment. J. Žáček, Institute of Particle and Nuclear P hysics, Charles University in Prague. Institute of Physics of the Academy of Sciencies of the Czech Republic
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Czech participation in the H1 experiment J. Žáček, Institute of Particle and Nuclear Physics, Charles University in Prague • Institute of Physics of the Academy of Sciencies of the • Czech Republic • Institute of Particle and Nuclear Physics, Faculty of Mathematics and • Physics, Charles University in Prague • Participation since 1987: subdetector construction • design and production of electronics • program development • data analysis H1 Prague group : 5 senior physicists, 4 PhD students Financial support : Ministry of Education, Youth and Sports running costs , visits at DESY and conferences
H1 experiment Prague contribution: Calorimeter SPACAL (1994-1995) p Liquid argon Calorimeter (1987-1990) Backward silicon tracker (1996-1997) e Forward silicon tracker (2001-2005)
Prague contribution to the Forward silicon tracker (FST) • Testing of silicon sensors (laser tests etc. .. } • Development and production of electronics • Development of the slow control and DAQ • Simulation of FST • Analysis of data taken in 2004 ( D* production) FST was constructed mainly by DESY-Zeuthen and Prague The first FST data were taken in 2004 J. Žáček
Forward and backward silicon detectors p BST electronics cards (repeaters) e FST wheels of strip Si sensors electronics cards J. Žáček
converters Si sensor wheels repeaters J. Žáček Converters + repeaters were designed and produced in Prague
Converter card: power supply and control circuits for 8 data channels J. Žáček
Track reconstruction in FST Reconstructed event FST wheels FST track residuals longitudinal view J. Žáček transverse view
Very Forward proton spectrometer (VFPS) Installed in 2003. Detection of diffracted protons scattered in the beam pipe H1 e VFPS, 220 m p IP Beam pipe t < 0.25 GeV2 VFPS2 J. Žáček VFPS1 3.7 m
VFPS Czech participation: Reconstruction of tracks in VFPS (in collaboration with Belgian H1 group) A method based on the neural network was developed Goal: From hits in the VFPS to get proton track parameters in the interaction vertex. This is a complicated procedure since there are accelerator magnets which have influence on proton tracks.
Data analysis Measurement of dijet production at low Q2 at HERA e + p e + X Pp q Q2 = - (k – k’ )2 , y = Pp k Q2 jet g Direct photon interactions e e LO undetected jet p p NLO e Resolved photon interactions LO p NLO LO
Measurement of dijet production at low Q2 at HERA DATA 99/00, 2 < Q2 < 80 GeV2 GOAL : Detailed comparison of triple differential cross sections (e.g. d3s / dQ2dy dh* , h* jet rapidity in g-p CMS) with generators and NLO QCD calculations Generators : HERWIG,LO MC, DGLAP evolution, dir + res photons + parton showering+ cluster hadronisation CASCADE,LO MC,unintegrated PDF+ CCFM evolution scheme + LUND string hadronisation NLO calculations: JETVIP J. Žáček
Measurement of dijet production at low Q2 at HERA 0.1 < y < 0.25 0.25 < y < 0.5 0.5 < y < 0.85 ● H1 data (pb) Generators HERWIG dir HERWIG dir+resT HERWIG dir+resT +resL CASCADE QCD calculations NLO JTEVIP dir NLO JTEVIP total h* -2 -1 0 -2 -1 0 -2 -1 • NLO QCD calculations underestimate data at high y • HERWIG – better agreement if the longitudinal photon is included
Dijets in difractive photoproduction DATA 99/00 , Q2 < 0.1 GeV2 ( photoproduction) , t < 1 GeV2 • Test of QCD factorisation in dijet diffractive photoproduction • Comparison of data with NLO calculations J. Žáček
Dijets in difractive photoproduction Motivation: Dijet diffractive cross section determined at TEVATRON is lower by a factor ~ 5 than the QCD calculation using HERA diffractive PDFs. Exporting HERA PDFs tothe Tevatron doesn’t work ?, factorisation breaking? Analogy of pp interactions and ep resolved photon interactions H1 data analysis is performed by our PhD student J. Žáček
Further activities and outlook Further activities: • Calibration of the VFPS with r mesons , data 2005/2007 • Calibration of final state hadronic energies • Development of the software package HZTOOL, which enables fast • comparison of theoretical calculations with published experimental • results Outlook: ~ next 4 years analysis of H1 data from 05-07 (~ 3 PhD thesis) - measurement of the longitudinal diffractive proton structure function - forward jets in diffraction J. Žáček