June 25, 2016 Mitglied der Helmholtz-Gemeinschaft The PANDA Experiment at FAIR XLIX International Winter Meeting on Nuclear Physics, Bormio 2011 | Tobias Stockmanns on behalf of the PANDA collaboration

What do we want to study? Confinement Why are there no free quarks? Hadron mass Where is the mass of the proton coming from? Are there other color neutral objects? What is the structure of the nucleon? What are the spin degrees of freedom? 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 2

Main Physics Program Meson spectroscopy: D mesons charmonium glueballs, hybrids, tetraquarks, molecules Charmed and multi-strange baryon spectroscopy Electromagnetic processes (pp  e + e -, pp  , Drell-Yan) Properties of single and double hypernuclei Properties of hadrons in nuclear matter 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 3 part of the presentation

6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 4 2∙10 11 stored anti protons, GeV/c Foundation of the FAIR GmbH October, 2010

High Energy Storage Ring P max = 15 GeV/c High resolution: L = cm -2 s -1  p/p < 4x10 -5 High luminosity: L = 2·10 32 cm -2 s -1  p/p < Cooling: electron/stochastic Detector Injection HESR Electron cooler

PANDA Spectrometer Detector requirements: 4  coverage(partial-wave-analysis) high rates(2 x 10 7 annihilations/s) good PID( , e, , , K, p) momentum res.(~1%) vertexing für D, K 0 S,  (c  = 123  m for D 0, p/m  2) efficient trigger(e, , K, D,  ) no hardware trigger(raw data rate ~TB/s) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 6

PANDA Spectrometer Interaction point Antiproton beam 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 7

Micro-Vertex-Detector 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 8 p beam D+D+ D-D- ++ ++ -- -- K+K+ K-K- beam pipe (not to scale) c  = 315 µm p target

Micro-Vertex-Detektor 10 million pixel channels on 176 modules 200,000 strip channels on 254 modules Beam Target 40 cm 15 cm

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 10 Central Tracker STT or TPC TPC poster presentation by Martin Berger

Straw Tube Tracker Low mass, X/X 0 ~1%  11.5 kg Straw tubes (4580  2.5g)  Close-packed layers, pressurized p=2bar  Self-supporting strong wire & tube stretching  9 kg Mechanical frame   r  ~ 150  m,  z ~ 2.9 mm   p ~ 1% at B = 2 Tesla  dE/dx measurement for PID 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 11 Poster presentation by Pawel Kulessa and Krzysztof Pysz

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 12 DIRC Detector

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 13 TOF?

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 14 EM Calorimeter

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 15 Muon Detectors

PANDA Spectrometer 12 m 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 16 Luminosity Monitor

Panda luminosity monitor PANDA facility Goal of Panda luminosity monitor: Integrated luminosity with ~ 3% absolute precision Concept: Low t elastic scattering, Coulomb interference region Forward going antiproton, 3 < Θ < 8 mrad 4-layer Si-strip telescope at z ~ 10 m 20 cm between each layer 150 or 300 µm thick, 50 mm pitch, double sided

Why Antiprotons? Gluon rich process Gain ~ 2GeV in annihilation (low momentum transfer) B = 0 system All fermion-antifermion quantum numbers accessible Very high mass resolution in formation reactions High angular momentum accessible (high L states) Formation: All J PC allowed for (qq) accessible in pp Only J PC = 1 -- allowed in e + e - 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 18

Example: χ c1,2 Invariant mass reconstruction depends on the detector resolution ≈ 10 MeV Formation: Resonance scan: Resolution depends on the beam resolution Gaiser et al., Phys. Rev. D34 (1986) 711 CrystalBall (SLAC): ± 4 MeV/c 2 Andreotti et al., Nucl. Phys. B717 (2005) (E835): ± MeV/c 2 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 19 Production: Interpretation of many states depends on width of states

D spectroscopy is the QCD analogon to hydrogen atom Open Charm Spectrum B. Aubert et al. (BaBar Collab.), Phys. Rev. D 74 (2006) D. Besson et al., Phys. Rev. D68, (2003) B. Aubert et al., Phys. Rev. Lett. 90, (2003) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 20

Open Charm Spectrum B. Aubert et al. (BaBar Collab.), Phys. Rev. D 74 (2006) D. Besson et al., Phys. Rev. D68, (2003) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich : Discovery of the narrow D s (2317) by BaBar in the decays: Confirmed by CLEO and Belle 2003: Discovery of the narrow state D sJ (2460) + in the decay: confirmed by Belle and BaBar Three more states found: D sJ (2710) +, D sJ (2860) +, D sJ (3040) + Problem: Width of D s (2317) and D s (2460) below detector resolution < 4 MeV

Decay width of D s0 * (2317) Part of the table from A. Faessler, et al. Phys. Rev. D 76 (2007) 133 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 22 “We therefore conclude that the decay width of the D s0 *(2317)  D s  0 can be a good criterion for testing the nature of the D s0 *(2317)” Feng-Kun Guo, Christoph Hanhart, Siegfried Krewald, Ulf-G. Meißner “We therefore conclude that the decay width of the D s0 *(2317)  D s  0 can be a good criterion for testing the nature of the D s0 *(2317)” Feng-Kun Guo, Christoph Hanhart, Siegfried Krewald, Ulf-G. Meißner

Excitation functions for D s (2317) excitation function for D s width of: 10 keV 100 keV 500 keV straight line: smeared with beam momentum resolution of dashed line: without smearing  s MeV M.C. Mertens PhD thesis /25/2016Tobias Stockmanns, IKP – FZ-Jülich 23 Count rate (a.u.)

Simulation results: energy scan M. Mertens PhD thesis  = 100 keV M sum = M miss (D s ) + M(D s ) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 24

Smearing of excitation function  s MeV excitation function without smearing smeared excitation function 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 25 Count rate (a.u.)

Smearing of excitation function  s MeV excitation function without smearing smeared excitation function y error given by statistics x error given by beam resolution (scaled by 10) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 26 Count rate (a.u.)

Smearing of excitation function  s MeV excitation function without smearing smeared excitation function 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 27 Count rate (a.u.)

Simulation results: energy scan M. Mertens PhD thesis  = 100 keV  = 500 keV σ vs √sχ 2 vs Γ ΔM vs Γ 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 28 4 days measurement per point at high luminosity

Charmonium Spectrum 1 fm C C Charmonium is a bound state of a cc. The QCD analog of positronium in QED 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 29

Charmonium Spectrum Region above DD-threshold - very hot topic 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 30 All states below DD- threshold found Some inconsistences Resolution of mass and width of certain states poor All states below DD- threshold found Some inconsistences Resolution of mass and width of certain states poor

Actual Picture of the Charmonium Spectrum Godfrey: Proceedings of the DPF 2009 conference 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 31 X(3872) Z-States

X(3872) First XYZ state observed 2003 by Belle Later confirmed by BaBar, CLEO, CDF and D0 Very close to the D *0 D 0 threshold J PC = 1 ++ most probable Hot candidate for a molecule  (X3872) < 2.3 MeV 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 32 Precision measurement from CDF Phys. Rev. Letter 103 (2009)

Simulation Studies of X(3872) Two models for X(3872) studied by Chen and Ma: loosely bound molecule exited state of conventional charmonium  c1 (2P) Cross section as function of width of state: Possible to distinguish both models by cross section if width is known precisely 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 33 Chen and Ma, Phys. Rev. D 77 (2008) Solid line: molecule Dashed line: charmonium  (MeV) 0.51  (nb) 206 N(/day) high lumi622186

Simulation results pp  X(3872)  J/  +  - Mass spectra at 10 different energies  = 1 MeV, S/B = 2:1 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 34 T. Randriamalala PhD thesis in preparation

Results 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 35 T. Randriamalala PhD thesis in preparation

Charged Z states Three charged states observed by Belle: Z + (4051), Z + (4250), Z + (4430) All in decay to  (2S)  + and  c1  + Z(4430) not found by BaBar A charge state decaying to charmonium is a smoking gun for exotic states 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 36 Dalitz analysis of B  K  +  (2S) (Belle 2009) Solid line: Fit to Dalitz plot with a single  (2S)  + resonance Dashed line: without resonance R. Mizuk et al., Phys. Rev. D 80 (2009)

How can PANDA contribute? simulation studies for several channels and √s : J/ψπ + π -, J/ψπ 0 π 0, χ c γ  J/ψ γγ, J/ψ γ, J/ψ η, η c γ direct formation in pp: line shapes ! d target: pn with p spectator tagging, e.g. Z - (4430) ≈ 100 events/day ≈ 40 events/day S/N =25 ε = 32 % S/N = 2 C. Hanhart et al., PRD 76 (2007) J/     D 0 D *0 _ J/     D 0 D *0 _ E. Braaten, M. Lu, PRD 77 (2008) D0D00D0D00 _ 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 37

qq forbidden J PC values possible Exotic Hadrons Much more color neutral objects allowed than the observed: Exotics: qq qq q g qq q q q q Baryons Mesons Hybrids (qq)g Glueballs (gg) Multiquarks (qq)(qq) 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 38

Exotics production in pp collisions J PC exotic Exotic J PC would be clear signal Formation: only allowed J PC accessible Production: all J PC accessible 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 39

Physics Reach At 2  cm -2 s -1 accumulate 8 pb -1 /day (assuming 50 % overall efficiency)  (cc) states/day. pp   (3770)  D + D - (~3 nb)  K +/-  -/+  -/+ (~30 pb)  240 counts/day Total integrated luminosity 1.5 fb -1 /year (at 2  cm -2 s -1, assuming 6 months/year data taking). Fine scans to measure masses and widths to  100 keV Explore entire region below and above open charm threshold. Decay channels  J/  +X, J/   e + e -, J/    +      hadrons  DD 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 40

Conclusion & Outlook will be a versatile QCD experiment:  Large acceptance  Tracking and vertexing capabilities  Particle identification and calorimetry  Flexible data acquisition & trigger Novel techniques in detector and readout design 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 41

The PANDA Collaboration U Basel IHEP Beijing U Bochum U Bonn U & INFN Brescia U & INFN Catania U Cracow GSI Darmstadt TU Dresden JINR Dubna (LIT,LPP,VBLHE) U Edinburgh U Erlangen NWU Evanston U & INFN Ferrara U Frankfurt LNF-INFN Frascati U & INFN Genova U Glasgow U Gießen KVI Groningen U Helsinki IKP Jülich U Katowice IMP Lanzhou U Mainz U & Politecnico & INFN Milano U Minsk TU München U Münster BINP Novosibirsk LAL Orsay U Pavia IHEP Protvino PNPI Gatchina U of Silesia U Stockholm KTH Stockholm U & INFN Torino Politechnico di Torino U Oriente, Torino U & INFN Trieste U Tübingen U & TSL Uppsala U Valencia SMI Vienna SINS Warsaw U Warsaw More than 400 physicists from 55 institutions in 17 countries 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 42

Resonance Scan X(3872) – PANDA MC Exclusive final state pp →X(3872) each data point 2 days data taking full background Preliminary result: fitted width is ~20% larger than input, but  s) still ≤ 100 keV(this would be a syst. Error on the width of X(3872)) From S. Lange (Menu10) Preliminary stat. error only 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 43

Hadrons in the nuclear medium original idea: mass shift of charmed hadrons in nuclear matter D mesons: attractive potential and/or bound states predicted problem: large momentum transfer multistep processes required C. Garcia-Recio et al., arXiv: K. Tsushima et al., PRC 59 (1999) 2824 D-D- D0D0 D 0  208 Pb

K. Seth, Proc. Hirschegg 2001 p + A  J/  + X   +  - + X _ p + A  J/  + X  e + e - + X _  measure cross section as function of A and p p  deduce J/  N dissociation cross section at lower, well- defined J/  momentum _ e+e+ e-e- note:  pA  J/  X <<  pp  J/  need to detect S/B = ! _ _ P = e  dl Hadrons in the medium: J/ψ absorption related to QGP signal in HI collisions

first detailed simulations of 4.05 GeV/c p + 40 Ca  J/  + X  e + e - + X reconstruction efficiency  signal = 0.73 σ peak ~ 0.3 nb → #J/ψ ~ 200 /day at maximum luminosity background seems to be controllable Hadrons in the medium: J/ψ absorption σ J/ψN extracted from A-dependence signal π+π-π+π- extrapolated background input: σ J/ψN = 4.2 mb fit: σ J/ψN = 4.34 mb

Baryon spectroscopy Similar cross section for annihilation to mesons or baryons Baryons formed largely via excited states Energy range of PANDA sufficient to produce complete set of baryons with strangeness up to the continuum region Lower states of baryons with open and hidden charm accessible 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 47

Baryon spectroscopy characteristic event topology of ΞΞ * and ΩΩ * events ~μb cross section for ΞΞ  ~10 7 Ξ /day produced with full luminosity A.B. Kaidalov, E.P.Volkovitsky, ZPC 63 (94) 514 6/25/2016 Tobias Stockmanns, IKP – FZ-Jülich 48

Simulation: pp  Ξ + Ξ - π 0 benchmark channel for the study of Ξ resonances no empty regions or discontinuities in Dalitz plot Ξ - π 0 mass resolution ~4 MeV 6/25/2016Tobias Stockmanns, IKP – FZ-Jülich 49