quests for panda experiment

Quests forPANDA experiment

Eugene A. StrokovskyJoint Institute for Nuclear Research

Veksler-Baldin Laboratory of High Energyfor the PANDA Collaboration

at ConferenceNEW TRENDS IN HIGH-ENERGY PHYSICS

(experiment, phenomenology, theory)Alushta, Crimea, Ukraine, September 3 - 10, 2011

1E.A.S., Alushta, 09.09.11

2E.A.S., Alushta, 09.09.11

Plan of the talk

The FAIR complex (Facility for Antiproton and Ion Research) The HESR (High Energy Storage Ring) and PANDA Detector(dedicated talk: Tibor Keri for PANDA Collaboration)PANDA for physics of strong interactions (main topics) Selected points of thePANDA Physics Program Conclusions

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The FAIR complex (Facility for Antiproton and Ion Research)

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From talk by B. Sharkov (March 2010 at PANDA meeting)

Research Communities at FAIR

100 m

Nuclear Structure & Astrophysicswith rare isotope beams, x10 000and excellent cooling

High EM Field (HI) _Fundamental Studies (HI & p)Applications (HI)

Plasma Physics: x600 higher target energy density 600kJ/g

Nuclear Matter Physics with35-45 GeV/u HI beams, x1000

Hadron Physicswith antiprotons of 1.5 - 15 GeV/c

Special Features:• 50ns Bunched beams• Electron cooling of secondary beams• SC magnets fast ramping• Parallel operation

SIS 100/300

HESR

SuperFRS

NESR

CBMHADES

FLAIRCR- RESR

Rare Isotope Production Target

AntiprotonProduction Target

5

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Planned beam parameter of the SIS100/300 facility

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Planned for 2016-2017Planned: after 2017

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The HESR (High Energy Storage Ring) and PANDA Detector

(dedicated talk: Tibor Keri for PANDA Collaboration)

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High resolution mode

• p/p ~ 10 (electron cooling)• Luminosity: 1031 cm s

PANDA

injection

• Production rate 2x107/sec• Pbeam = 1.5 - 15 GeV/c (2.25 < s < 5.47 GeV)• Nstored = 5x1010 antiprotons• Internal Target

High luminosity mode

• Luminosity: 2 x 1032 cm s • p/p ~ 10 (stochastic cooling)

Storage and acceleration of antiprotons

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Basel, Beijing, Bochum, Bonn, IFIN Bucharest, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, GSI, Inst. of Physics Helsinki,

FZ Jülich, JINR Dubna, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern,

BINP Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, Stockholm,

U Torino, INFN Torino, Torino Politecnico, Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU

Warsaw, AAS Wien

Basel, Beijing, Bochum, Bonn, IFIN Bucharest, Catania, Cracow, Dresden, Edinburg, Erlangen, Ferrara, Frankfurt, Genova, Giessen, Glasgow, GSI, Inst. of Physics Helsinki,

FZ Jülich, JINR Dubna, Katowice, Lanzhou, LNF, Mainz, Milano, Minsk, TU München, Münster, Northwestern,

BINP Novosibirsk, Pavia, Piemonte Orientale, IPN Orsay, IHEP Protvino, PNPI St. Petersburg, Stockholm,

U Torino, INFN Torino, Torino Politecnico, Trieste, TSL Uppsala, Tübingen, Uppsala, Valencia, SINS Warsaw, TU

Warsaw, AAS Wien

Austria – Belarus - China - Finland - France - Germany –India - Italy – NetherlandsPoland – Romania - Russia – Spain - Sweden – Switzerland - U.K. – U.S.A…

At present collaboration has more than 430 physicists

from 56 institutions of 17 countries

http://www.gsi.de/panda

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PANDA for physics of strong interactions (main topics)

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PANDA Physics Program

FAIR/PANDA/Physics Bookhep-ex0903-3905v1

QCD BOUND STATES CHARMONIUM Gluonic excitations (hybrids, glueballs) Strange and charmed baryons

NON-PERTURBATIVE QCD DYNAMICS HADRONS IN THE NUCLEAR MEDIUM PHYSICS OF HYPERNUCLEI NUCLEON STRUCTURE

Generalized distribution amplitudes (GDA) Matveev-Muradyan-Tavkhelidze-Drell-Yan Electromagnetic formfactors (time-like region) viapp e+e- (or +-)

ELECTROWEAK PHYSICS CP-Violation and Mixing in the Charm-Sector CP-Violation in Hyperon DecaysRare Decays

The study of QCD bound states is of fundamental importance forquantitative understanding of QCD.

Precision measurements are needed to distinguish between the different approaches and identify the relevant degrees of freedom.

Example of hard exclusivemeson production

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QCD Systems to be studied in Panda

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CHARMONIUM

NOTE: open problems and questions concerning charmonium were presented by I.Denisenko in his talk on Sept. 4 (Sunday) about BES-III results.

Therefore here only main PANDA specific features are considered.

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Charmonium Spectroscopy

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Resonance Scan in pp AnnihilationThe cross section for the resonance formation processpp cc final stateis given by the Breit-Wigner formula:

The number of detected final state events (Nevent) is a convolution of the BW

cross section and the beam energy spread function f(Ecm,Ecm):

Measured rate (yield)

Beam profile

Resonance formation

cross section

CM Energy

The resonance mass MR , total width R and the product BrinBrout of branching ratios into the initial and final state can be extracted by measuring the formation rate Nevent for that resonance as a function

of the cm energy Ecm.

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3500 3520 MeV3510

CB

all

ev./

2 M

eV

100

ECM

CBallE835

1000

E 8

35 e

v./

pb

c1

Cball: Edwards et al. PRL 48 (1982) 70

E835: Ambrogiani et al., PRD 62 (2000) 052002

Mass resolution with PANDA: factor ~ 10 better:p/p = 10-5 M < 20 keV

From A.Gillitzer, talk at “QCD exotics”, Bad Honnef, Jan. 2005

• In e+e- annihilation via virtual photon: only states with JPC = 1--

Other states: only via radiativetransitions, 2-photon processes etc.

Good mass resolution for JPC = 1-- ; Other states - detector is limited. Measurement of sub-MeV widths: impossible.

• in pp annihilation all mesons can be formed

_

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• At 21032 cm-2s-1 accumulate 8 pb-1/day (assuming 50% overall efficiency) 104107 (cc) states/day. Total integrated luminosity: 1.5 fb-1/year (at 21032cm-2s-1, assuming 6 months/year data taking).• Improvements with respect to Fermilab E760/E835: - Up to 10 times higher instantaneous luminosity. - Better beam monochromaticity: p/p = 10-5(FAIR) vs 210-4 (FNAL) - Better detector (higher angular acceptance, magnetic field, ability to detect hadronic decay modes).• Fine scans to measure masses to 100 KeV, widths to 10 %.• Explore entire region below and above open charm threshold.• Decay channels:

J/+X , J/ e+e-, J/ +-

hadronsDD

• Precision measurement of known states• Find missing states (e.g. D states)• Understand newly discovered statesGet a complete picture of the dynamics ofGet a complete picture of the dynamics ofthe the cc system.cc system.

Charmonium at PANDA

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NON-PERTURBATIVE QCD DYNAMICS

In the quark picture hyperon pair production either involves the creation of a quark-antiquark pair or the knock-out of such pairs out of the nucleon sea. Hence, the creation mechanism of qq pairs and their arrangement to hadrons can be studied by measuring the reactions of the type pp YY, where Y is a hyperon. By comparing several reactions involving different quark flavours, the OZI rule (and it's possible violation) can be tested for different levels of disconnected quark-line diagrams separately.

In particlular, the reactions are interesting. Here some spin observables can be measured, including those for the case.

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Polarization of from

MC simulation

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Study of the OZI rule violation at PANDAStudy of the LEAR unresolved puzzles:

Annihilation into , , , f’2(1525), Pontecorvo reactions pdn, K+-, K0 (high 4-momentum transfer squared!)

Search for effects of nucleon polarized strangeness

From talk by M.G.Sapozhnikov (ITEP, 2008)

COMPASS:

If it were a normal quark reaction

• ()exp ~ 4 b• why is it so large?• () is not measured

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Strong violation of the OZI rule was found in:• pp•pp, •pp (3S1)•pdn (Pontecorvo reaction)

Does it depend upon: • spin• orbital angular momentum• momentum transfer• Isospin?

In experiments at LEAR

(M.G.S. (ITEP, 2008))

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pd n : highest momentum transfer to meson produced inpp or pd interactions.

R(n/n) = (15629) 10-3

How will it change with energy?Two-step model: pd n 1) pp 2) N N

R(n/n) - decreases with energyIs it the correct model?

pd K+- , K0 R(K+- / K0 )=0.920.15 (exp)

= 0.012 (theory)

Pontecorvo reactions (lightest nuclei case)

M.G.S. (ITEP, 2008)

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Luminosity of HESR: L =2 1032 cm-2 s-1

Cross section = 4 b at 1.4 GeV/cBR of charged mode =0.25Registration efficiency = 0.01

N = L = 2 1032 4 10-30 0.25 0.01 = 2 s-1

Best world statistics – 1.5 hours pp (K* K*, ) must be measured

pp at PANDA

Search for the tensor glueball

pp, , K* K*, as well

M.G.S. (ITEP, 2008)

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HADRONS IN THE NUCLEAR MEDIUM

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The topic “hadrons in medium” has rather long history. The pre-historical examples:

life-time of neutron in stable nuclei drastically differs from it's life-time in the emptyspace; life-time of the -hyperon in free state differs from it's life-time in hypernuclei and depends on the atomic number of a nuclei.

Next stage came with pions in nuclei and with the problem of the pion condensate.

Here the contributions by A.Migdal, G.Brown, T.Ericsson and M.Ericsson, W.Weise must be mentioned. Good lessons were obtained in inclusive and exclusive experiments on excitation of the -isobar in nuclei (end of ‘80-begin of ‘90). They stimulated theorists; contributions by E.Oset, V.Dmitriev, S.Fayans, S.Hirenzaki and others must be mentioned with respect to the topic under discussion. One of the approaches appeared at that time was partial restoration of the SU(4) symmetry in nuclear medium. Another approach was based on collective phenomena when pion propagates in (finite !) nuclear medium. At last decades new aspect was found by theorists and experimentalists. That was related with the deeply bound pionic atoms and with the subthreshold (or cumulative) production of K+ and K-. It resulted in concept of the partial restoration of the chiral symmetry in nuclear medium. It is this concept which is in use at modern discussions of the topic.

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photoabsorption

Deuteron targetFermi-motion of a nucleon

free proton

Total cross section

(p,n)

(3He,t)

-propagation and in nuclear matterChange of the -peak position and width in nuclei

(also in (t,3He), (p,p’)) A>6

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Measure J/ and D production cross section in p annihilation on nuclear targets. Lowering of the D+D- mass would allow charmonium states to decay into this channel, thus resulting in increase of width:(1D) 20 MeV 40 MeV(2S) .28 MeV 2.7 MeVStudy relative changes of yield and width of the charmonium states.In medium mass to be reconstructed from dilepton (cc) or hadronic decays (D)

Light quarks are sensitive to quark condensate(cc) states are sensitive to gluon condensateD mesons are the QCD analog of the H-atom.–chiral symmetry to be studied on a single light quark–theoretical calculations disagree in size and sign of mass shift (50 MeV/c2 attractive – 160 MeV/c2 repulsive)

Example of mass spectracalculations

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Other points concerning hadrons in the nuclear medium

For details see FAIR/PANDA/Physics Book (hep-ex0903-3905v1)

Charmonium dissociation The goal is to measure total cross section of the J/ - nucleon interaction. Themethod: measuring A-dependence of the J/ yield, detecting J/ by e+e- or +- modes. Similarly (with some differences) ’ dissociation can be studied.Production of antibaryons and antikaons off nucleiThe goal is to extract information about antiproton and anti- (as well as anti-kaon) nuclear potential by implanting these particles into the interior of a nucleus. This can be done at kinematics close to the recoiless kinematical condition by choosing proper antiproton energy.

Colour transparency The idea is to compare yields of exclusiveproduction of hadron pairs at large angles (closeto 90 degr. c.m.) on proton and nuclear target and extract the so-calledtransparency ratio . The reactions are:

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PHYSICS OF HYPERNUCLEI

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Hypernuclei, systems where at least one nucleon is replaced by at least one hyperon (Y), allow access to a whole set of nuclear states with extra degree of freedom: the strangeness.• Probe of nuclear structure and it's possible modifications due to the hyperon.• Test and define shell model parameters.• Description in term of quantum field theories and EFT.

• Study of the YN and YY forces; baryon-baryon interaction.• Weak decays (N suppressed, NNN and NN allowed weak interaction of 4-baryons)• Hyperatoms (or multi-strange atoms)• Hypernuclei as doorway to exotic quark states (like H-dibaryon).

• Experimentally: more than 50 years of study 35 single, 6 double hypernuclei established

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- capture:

- p + 28 MeV

-3 GeV/c

Kaons_

trigger

p_

2. Slowing down and capture

of insecondary

target nucleus

2. Slowing down and capture

of insecondary

target nucleus

1.Hyperon-

antihyperonproduction

at threshold

1.Hyperon-

antihyperonproduction

at threshold +28MeV

3. -spectroscopy

with Ge-detectors

3. -spectroscopy

with Ge-detectors

Production of Double Production of Double HypernucleiHypernuclei

-(dss) p(uud) (uds) (uds)

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The PANDA experiment will use the antiproton beam from the HESR colliding with an internal proton (for a number of topics – nuclear) target and a general purpose spectrometer to carry out a rich and diversified hadron physics program. The experiment is being designed to fully exploit the extraordinary physics potential arising from the availability of high-intensity, cooled antiproton beams. The aim of the rich experimental program is to improve our knowledge of the strong interaction and of hadron structure. Significant progress beyond the present understanding of the field is expected due to improvements in statistics and precision of the data.

Start of the physics is planned from end of 2017(i.e. in 6 years)

For details see FAIR/PANDA/Physics Book (hep-ex0903-3905v1)

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PANDA Detector

The detector description: in dedicated talk by Tibor Keri

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THANK YOU!

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Backups

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DVCS can be described by the handbagdiagram, as there is factorisation between the upper `hard' part of the diagram which is described by perturbative QCD and QED, and a lower `soft' part that is described by GPDs.

The handbag diagram may describe the inverted WACS process pp at PANDA energies.