COLLABORATION IN THE HERA-B EXPERIMENT

COLLABORATION IN THE HERA-B EXPERIMENT Armando Policarpo1,3, António Amorim2,4, João Carvalho1,3 (scientific coordinator), Helmut Wolters1,5 Students: João Bastos (Ph.D.), Vasco Amaral (Ph.D.), António Oliveira (M.Sc.) 1-LIP-Coimbra & 2-LIP-Lisboa (with 3-FCTUC, 4-FCUL & 5-UCP) CERN Fund 5th December 2000

Physics * year 2000 run was very important for the Hera-b experiment: all the effort was put in the commissioning of the full detector * strong experimental competition in USA and Japan (with important results in 2000) * CP violation in the B system is the main goal but other interesting measurements are possible (as charm physics, QCD, and Drell-Yan) CERN Fund 5th December 2000

Hera-b Detector * detector was almost fully commissioned during the long run (until the end of August 2000) | HERA is now in a long shutdown for luminosity upgrade * some measurements were already done (e.g. spectroscopy) | trigger to be improved * problems with the main tracking (inner and outer) and with muon chambers | first level trigger still needs a lot of improvement to achieve the final goal CERN Fund 5th December 2000

Muon ECAL RICH Tracking Magnet Vertex CERN Fund 5th December 2000

Participation in the experiment Experiment Database * our group has full responsibility in the implementation of the experiment database (very important and demanding task) | fundamental system * we keep one person full time at DESY * the system is working | its functionality is being improved CERN Fund 5th December 2000

RICH * the main effort is concentrated now on data analysis, in particular the correlation of the RICH information with other detectors, in ring reconstruction algorithms, and the test of particle identification (e.g. spectroscopy) Data simulation and analysis * running of the Hera-b Monte Carlo and reconstruction package (ARTE) in local computer * transfer and analysis of acquired and simulated data samples * study of the B0 J/ K* decay channel for the measurement of B0 lifetime and mixing * data analysis (selection of J/ e+ e- and J/+-, vertexing and tagging) CERN Fund 5th December 2000

q2 1/p2 F K* pK mass KK mass CERN Fund 5th December 2000

Students * the group has three students (two for Ph.D. and one for M.Sc.) * eventually more students will be attracted (there are other students interested, if we have funding), in particular from related areas (e.g. computation engineering) * our group made a considerable contribution to the experiment setup, and now can do a very good work in data analysis | one of us was the analysis coordinator for some time CERN Fund 5th December 2000

Financing * enough computation power will have to be installed locally in order to contribute to the overall data simulation and analysis effort (a Linux computer farm plus devices for data transfer) * the experiment has to contribute to DESY to cover part of the running costs (our group contribution is about 3% of the total) * project grants for students (and post-docs) are needed to cover the period before they can apply to a FCT grant (this is fundamental to strengthen the group) CERN Fund 5th December 2000

Summary and Conclusions * Hera-b faces a fierce international competition in its main subject (but it can contribute to other physics subjects); the detector is on the final commissioning phase * important work already developed by the group (e.g. database implementation) which will be continued * an important number of students were attracted to the experiment * data analysis is now the most important task of the experiment; the group will be deeply involved in this work | it can also contribute to the detector upgrade and repair during the shutdown (in the RICH and database) CERN Fund 5th December 2000

Preliminary results (online plots) J/+- J/e+e- Inv. Mass (+  -) (GeV) Inv. Mass (e+e-) (GeV) CERN Fund 5th December 2000

COLLABORATION IN THE HERA-B EXPERIMENT