The NA49 Proposal Measurement of p +/-, K+/- production x-sections for the T2K n beam

1. The NA49 ProposalMeasurement of p+/-, K+/- production x-sections for the T2K n beam Alessandro Bravar

2. T2K off axis beam far  beam 295 km near far-to-near flux ratio (T2K beam MC prediction) • Near and far detectors see different solid angles: • far detector: pointlike source at 2o • near detector: extended source 1o to 3o • (wide off axis angular range) • complicated far to near flux ratio to get the flux ratio right need to know the details of the hadron production instead of hadronization models (fluka, gcalor, etc.) prefer to use measured pion and kaon x-sections note: no measurements at these incident beam energies (30 to 50 GeV) T2K not statistics limited (nm disappearence) required error on flux ratio ~ 2 % or smaller ~ 500 k p events needed for this precision far peak shifted to higher energy (angular acc.) extended source for near detector depends on the details of pion and kaon production kinematics

3. T2K n parent hadron phase space p+ K+ angle (mrad) angle (mrad) momentum (GeV) momentum (GeV) need to cover all this kinematical region and identify the outgoing hadrons K component important for ne appearance signal (background) requires: large acceptance particle ID

4. NA49 setup NA49-future: Study of hadron production in collisions of protons and nuclei at the CERN SPS beam TPC ToF

5. Typical proton event outgoing beam veto telescope incoming beam definition Heavy Ion event vertex resolution sz ~ 5 mm momentum resolution Dp/p2 ~ 10-4

6. NA49-future physics goals • measurements of hadron production in A+A collisions, in particular fluctuations and long range correlations, with the aim to identify the properties of the onset of deconfinement and search for the critical point of strongly interacting matter • measurements of hadron production in p+p and p+A interactions needed as a reference data for better understanding of A+A reactions, in particular correlations, fluctuations and high transverse momenta will be the focus of this study • measurements of hadron production in hadron-nucleus interactions needed as reference for neutrino (T2K) and cosmic ray (Pierre Auger and Kaskade) experiments

7. NA49-future Collaboration NA49-future collaboration (under formation and expanding) 80 physicists from 22 institutes and 14 countries: University of Athens, Athens, Greece University of Bergen, Bergen, Norway KFKI IPNP, Budapest, Hungary Cape Town University, Cape Town, South Africa Jagellionian University, Cracow, Poland Joint Institute for Nuclear Research, Dubna, Russia Fachhochschule Frankfurt, Frankfurt, Germany University of Frankfurt, Frankfurt, Germany Cern, Geneva, Switzerland University of Geneva, Geneva, Switzerland Forschungszentrum Karlsruhe, Karlsruhe, Germany Swietokrzyska Academy, Kielce, Poland Institute for Nuclear Research, Moscow, Russia LPNHE, Universites de Paris VI et VII, Paris, France Pusan National University, Pusan, Republic of Korea Faculty of Physics, University of Sofia, Sofia, Bulgaria St. Petersburg State University, St. Petersburg, Russia State University of New York, Stony Brook, USA IFC, IFIC, CSIC and Universidad de Valencia, Valencia, Spain Warsaw University of Technology, Warsaw, Poland University of Warsaw, Warsaw, Poland Rudjer Boskovic Institute, Zagreb, Croatia

8. NA49 advantages • advantages • the experiment exists (hardware and software) • well understood detector • large acceptance TPC • TPC works remarkably well (2006 test run) • particle ID (dE/dx and ToF) • almost no impact on SPS running (low intensity p beam) • modest investment for upgrades ~ 2 M CHF • some –’s (work to be done) • 15 year old equipment • very slow DAQ (old technology) new TPC readout under development (20 x faster) • limited ToF coverage possible extensions being considered

9. Particle ID (dE/dx in TPC & ToF) p: 5 – 6 GeV p > 4 GeV TPC ToF 1 < p < 4 GeV: ToF alone p > 4 GeV dE/dx + ToF

10. TPC readout 1 PC New mother boards Control cards 24 8 bits readout channel serial connection PCI or PCI express old readout FE mother bord ~ 150 k channels receiver DDL receiver Front-End Fiber connection total cost ~ 400 k CHF, ready for 2008 run (proto in 2007)

11. NA49 ToF ToF wall 27 cassettes per shelf 3 shelfs 891 channels in total 891 scintillators ~ 3 x 6 cm2

12. NA49 acceptance TPC acceptance ToF acceptance « standard » B fields rescaled to 30 GeV running In order to cover lower momenta / larger angles with ToF consider different settings of NA49 apparatus: lower magnetic fields target position use only one magnet … several solutions possible (Vadim did already some encouraging simulations …) We are considering also to extend the ToF coverage T2K hadron beam phase space

13. Acceptance Studies produced in opposite direction as magnetic field bending produced in same direction as magnetic field bending nominal target position upstream of vertex TPCs target between the vertex TPCs (will use only the second TPC) can cover the relevant phase space by moving the target and adjusting the magnetic fields

14. p productionCross Sections(Pbeam = 158 GeV) total systematical error (p+ and p- production) statistical error ~ few % ~ 400 k reconstructed tracks

15. Kaonproduction ratios transverse mass ~ 10 x smaller s compared to p systematical error: ~ 5% (~10 % acc. edges)

16. Next steps & run plan • submit NA49-future proposal on Oct. 30. (don’t expect immediate approval) • beam request for 2007 (independent approval) • 2007 run (in October) 30 days with 30 GeV protons 90 cm long C target (T2K) 2 to 4 M triggers, 500 k good events will already yield a significant measurement • 2008 run new faster DAQ 30, 40, 50 GeV proton beams (in J-PARC PS energy range) C targets with different thicknesses (reinteractions, absolute x-sections) • 2009 and later more beam if required