Physics with Muon and Hadron Beams at COMPASS Reiner Geyer for the COMPASS collaboration Hadron Structure 2009

Daniele Panzieri 2 EINN07 - Milos september 2007 N SPS LHC SPS Beams: protons up to 400 GeV/c. 4.8s/16.2 spill Secondary hadron beams (p,π ±,K ± ) with 2·10 8 particles/spill Tertiary Muons: 2·10 8 particles/spill with 80% polarization

Hadron Structure The COMPASS Collaboration Bielefeld, Bochum, Bonn (HISKP), Bonn (PI), Burdwan and Calcutta, CERN, Dubna (LPP and LNP), Erlangen, Freiburg, Mainz, Lisbon, Moscow (INR), Moscow (LPI), München (LMU), München (Technische Universität), Prague, Protvino, Saclay, Tel Aviv, Torino (University and INFN), Trieste (University and INFN), Warsaw (SINS), Warsaw (TU), Yamagata 240 Physicists from more than 20 Institutes Experiments with Muon Beam -ΔG/G 1 -g 1 -Transverse Spin Effects -Flavor Decomposition of Spin Distribution Functions -Excl. Vector Meson Production -Lambda Polarizations Future: -DVCS Experiments with Hadron Beams -Pion and Kaon Polarizabilities -Diffractive Production of Exotic States -Search for Glueballs -Light Meson Spectroscopy Future: -Drell Yan

Historical Overview 2002, 2003, 2004, 2006 and 2007 data taking with 160 GeV, polarized μ beams: – LiD polarized target (~polarized deuterons) –2007 NH3 polarized target (~polarized protons) –Both longitudinal and transverse polarized targets TB of data corresponding to 5·10 10 events Pilot run in 2004 for hadron program Few days of effective data taking. 2008: Hadron Beams for diffractive scattering. Physics Results Muon Beams: ΔG/G, ΔΣ, Transversity, Flavor Decomposition, Pentaquark, Exclusive Production of Vector Mesons, Cahn Asymmetries. Hadron Beams: PWA in diffractive Scattering. South Africa, November

Polarized Deep Inelastic Scattering Hadron Structure

The First Moment of g 1 first moment of g 1 “Spin crisis” EMC 1987 Contrary to naive expectations, the spin of the nucleon is not only carried by the quarks.

Hadron Structure

From COMPASS Hadron Structure Error is a factor 2 bigger without COMPASS NLO QCD Fit of world data ΔΣ = Δu + Δd + Δs =0.30 ± 0.01(stat)±0.02(evol)

Hadron Structure 2009 Where is the Proton Spin From the pattern of the spin structure functions we expect more generally: Experiment ΔΣ = Δu + Δd + Δs

Flavor decomposition of Nucleon Structure South Africa, November Alexander Korzenev: Measurement of the Spin Structure of the Proton by COMPASS

Hadron Structure Direct measurement of ΔG/G Two approaches to tag PGF in COMPASS q = c: Open Charm D 0, D * decay q = u, d, s: High- p t Hadron Pairs Photon Gluon Fusion (PGF) Photon Gluon Fusion Spin dependence of the basic-processes calculable via pert. QCD

ΔG/G from High p t Hadron Pairs Hadron Structure Q 2 >1 Dominated by: Open charm production dominated by PGF: Cleanest but most difficult to measure!

Hadron Structure 2009 Open charm at COMPASS Photon-gluon fusion: 1.2 D 0 per PGF cc event c c g BR 4 % D 0 from D * about 20 % or:

Hadron Structure The Compass Spectrometer SM1 SM2 Beam MuonWall E/HCAL RICH Target Two-stage spectrometer Tracking: VSAT+SAT+LAT Particle Id: RICH,  Calorimetry: ECAL, HCAL ~ channels up to 580 TB/year recorded Two-stage spectrometer Tracking: VSAT+SAT+LAT Particle Id: RICH,  Calorimetry: ECAL, HCAL ~ channels up to 580 TB/year recorded  /h beam: 160/190 GeV high beam intensity large angular acceptance broad kinematical range  /h beam: 160/190 GeV high beam intensity large angular acceptance broad kinematical range 50 m

Hadron Structure The Compass Spectrometer

Particle ID - The RICH Hadron Structure

Kπ Mass Spectrum Hadron Structure

Hadron Structure ΔG/G Results Interest in Orbital Momentum GPDs

Physics with Transverse Spin Hadron Structure Christian Schill: Transversity Measurements at COMPASS Stefano Takekawa: Spin physics in polarized Drell-Yan processes at COMPASS

Meson Spectroscopy Hadron Structure

Exotic States ? Hadron Structure Hybrids Candidates Glueball Candidates

Diffractive Scattering and Central Production Hadron Structure

First Results from the 2004 Pilot Run Hadron Structure

PWA Technique Hadron Structure

Waves used in step 1of PWA South Africa, November

Major Waves Hadron Structure

π 1 (1600) Hadron Structure

COMPASS in 2008 Hadron Structure

Target Region Hadron Structure

Trigger Hadron Structure

Statistics in 2008 Hadron Structure π - p  π - π + π - π + π - p, π - π 0 π 0 p, π - ηηp, π - π 0 p; K - p  K - π + π - p Matthias Schott: Physics with Kaons in the Final State

Hadron Run 2009 Hadron Structure Spectroscopy with positive beam –p beam with 25% pions, 190 GeV, LH2 target –“Central production” Spectroscopy with negative beam –π − beam with 3% kaons, 190 GeV, LH2 target –Diffraction with LH2 target (low t) –Diffraction with nuclear target –Primakoff Scattering Studies for future program (needed for delevopments) –DVCS test with muon beam and recoil det. –Drell-Yan test with π - beam

Proposal to Study DVCS at COMPASS Hadron Structure

Kinematical Range at COMPASS Hadron Structure

Feasibility Studies 2008 Hadron Structure day measurement 1/3 μ-intensity 1/6 of target length

Summary Muon Program –New results on polarized PGF and gluon polarizations. –New results on Transversity  Christian Schill. –New results on flavor decomposition of nucleon structure. –More data taking on longitudinal and transversal polarized proton target (2010 & 2011) in order to improve statistics. Hadron Program –Results on diffractive 3 π production from 2004 pilot hadron run. –A lot of new results to be expected from 2008 and 2009 on diffractive scattering and central production in different final states. Feasibility studies for DVCS and Drell Yan ongoing. Proposal under preparation. If successful data taking from ~ 2012 on. Hadron Structure

More Talks from HS2009 Christian Schill: Transversity Measurements at COMPASS Alexander Korzenev: Measurement of the spin structure of the proton by COMPASS Alexey Guskov: The possibility of pion polarizabilities measurements at COMPASS Matthias Schott: Studies of Kaonic final states at COMPAS Stefano Takekawa: Spin Physics in polarized Drell-Yan processes at COMPASS Ekaterina Perevalova: Logitundinal polarisation of the Λ and Λ-bar hyperons in COMPASS South Africa, November