1. R-ECFA, Prague, March 9, 2007 1 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

2. 2 H1 experiment e p Prague contribution: Calorimeter SPACAL (1994-1995) Liquid argon Calorimeter (1987-1990) Backward silicon tracker (1996-1997) Forward silicon tracker (2001-2005)

3. R-ECFA, Prague, March 9, 2007 J. Žáček3 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

4. R-ECFA, Prague, March 9, 2007 J. Žáček4 Forward and backward silicon detectors e p FST BST electronics cards (repeaters) wheels of strip Si sensors

5. R-ECFA, Prague, March 9, 2007 J. Žáček5 Si sensor wheels repeaters converters Converters + repeaters were designed and produced in Prague

6. R-ECFA, Prague, March 9, 2007 J. Žáček6 Converter card: power supply and control circuits for 8 data channels

7. R-ECFA, Prague, March 9, 2007 J. Žáček7

8. R-ECFA, Prague, March 9, 2007 J. Žáček8 Reconstructed event longitudinal view transverse view FST wheels Track reconstruction in FST FST track residuals

9. R-ECFA, Prague, March 9, 2007 J. Žáček9 Very Forward proton spectrometer (VFPS) Installed in 2003. Detection of diffracted protons scattered in the beam pipe 3.7 m IP t < 0.25 GeV 2 VFPS, 220 m H1 p e VFPS2 VFPS1 Beam pipe

10. 10 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.

11. 11 Data analysis Measurement of dijet production at low Q 2 at HERA e + p e + X  Q 2 = - (k – k ’ ) 2, y = jet undetected jet P p q P p k p p e e Direct photon interactions p e Resolved photon interactions Q2Q2 LO NLO LO NLO

12. R-ECFA, Prague, March 9, 2007 J. Žáček12 Measurement of dijet production at low Q2 at HERA DATA 99/00, 2 < Q 2 < 80 GeV 2 GOAL : Detailed comparison of triple differential cross sections (e.g. d 3  / dQ 2 dy d  *,  jet rapidity in  -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

13. 13 Measurement of dijet production at low Q2 at HERA ● H1 data HERWIG dir HERWIG dir+res T +res L CASCADE NLO JTEVIP dir NLO JTEVIP total 0.1 < y < 0.25 0.25 < y < 0.5 0.5 < y < 0.85  * * -2 -1 0 -2 -1 0 -2 -1 QCD calculations Generators NLO QCD calculations underestimate data at high y HERWIG – better agreement if the longitudinal photon is included (pb)

14. R-ECFA, Prague, March 9, 2007 J. Žáček14 Dijets in difractive photoproduction DATA 99/00, Q 2 < 0.1 GeV 2 ( photoproduction), t < 1 GeV 2 Test of QCD factorisation in dijet diffractive photoproduction Comparison of data with NLO calculations

15. R-ECFA, Prague, March 9, 2007 J. Žáček15 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 to the Tevatron doesn’t work ?, factorisation breaking? Analogy of pp interactions and ep resolved photon interactions H1 data analysis is performed by our PhD student

16. R-ECFA, Prague, March 9, 2007 J. Žáček16 Further activities and outlook Calibration of the VFPS with  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 Further activities: 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