Physics with the PANDA Detector at GSI Diego Bettoni Istituto Nazionale di Fisica Nucleare, Ferrara...

Physics with the PANDA Detector at GSI

Diego Bettoni

Istituto Nazionale di Fisica Nucleare, Ferrara

Riunione WG Fisica Adronica e dello SpinRoma, 7 Novembre 2005

D. Bettoni - PANDA at GSI 2

Outline

• Overview of the Project PANDA Physics Program

– Charmonium Spectroscopy

– Hybrids and Glueballs

– Hadrons in Nuclear Matter

– Proton electromagnetic form factors in the timelike region

• The PANDA Detector Concept• Timeline• Conclusions


The GSI FAIR Facility


The FAIR Complex


Primary Beams

•1012/s; 1.5 GeV/u; 238U28+

•Factor 100-1000 over present in intensity•2(4)x1013/s 30 GeV protons•1010/s 238U73+ up to 25 (- 35) GeV/u

Secondary Beams

•Broad range of radioactive beams up to 1.5 - 2 GeV/u; up to factor 10 000 in intensity over present •Antiprotons 3 - 30 GeV

•Cooled beams•Rapidly cycling superconducting magnets

Key Technical Features

Storage and Cooler Rings

•Radioactive beams•e – A collider

•1011 stored and cooled 0.8 - 14.5 GeV antiprotons

FAIR: Facility for Antiproton and Ion Research


Antiproton Physics Program

• Charmonium Spectroscopy. Precision measurement of masses, widths and branching ratios of all (cc) states (hydrogen atom of QCD).

• Search for gluonic excitations (hybrids, glueballs) in the charmonium mass range (3-5 GeV/c2).

• Search for modifications of meson properties in the nuclear medium, and their possible relation to the partial restoration of chiral symmetry for light quarks.

Topics not covered in this presentation:• Precision -ray spectroscopy of single and double hypernuclei, to

extract information on their structure and on the hyperon-nucleon and hyperon-hyperon interaction.

• Electromagnetic processes (DVCS, D-Y, FF ...) , open charm physics


The GSI p Facility

HESR = High Energy Storage Ring

• Production rate 2x107/sec• Pbeam = 1 - 15 GeV/c• Nstored = 5x1010 p

High luminosity mode• Luminosity = 2x1032 cm-2s-1 • p/p~10-4 (stochastic cooling)

High resolution mode• p/p~10-5 (el. cooling < 8 GeV/c)• Luminosity = 1031 cm-2s-1


The PANDA Collaboration

U BaselIHEP BeijingU BochumU BonnU & INFN BresciaU & INFN CataniaU CracowGSI Darmstadt TU DresdenJINR Dubna (LIT,LPP,VBLHE)U EdinburghU ErlangenNWU EvanstonU & INFN FerraraU FrankfurtLNF-INFN Frascati

U & INFN GenovaU GlasgowU GießenKVI GroningenU Helsinki IKP Jülich I + IIU KatowiceIMP LanzhouU MainzU & Politecnico & INFN MilanoU MinskTU MünchenU MünsterBINP NovosibirskLAL Orsay

U PaviaIHEP ProtvinoPNPI GatchinaU of SilesiaU StockholmKTH StockholmU & INFN TorinoPolitechnico di TorinoU Oriente, TorinoU & INFN TriesteU TübingenU & TSL UppsalaU ValenciaIMEP ViennaSINS WarsawU Warsaw

Spokesman: Ulrich Wiedner (Uppsala)

More than 300 physicists from 48 institutions in 15 countries


QCD Systems to be studied in Panda


Charmonium Spectroscopy

Charmonium is a powerful tool for theunderstanding of the strong interaction.The high mass of the c quark (mc ~ 1.5GeV/c2) makes it plausible to attempt a

description of the dynamical properties ofthe (cc) system in terms of non relativistic

potential models, in which the functionalform of the potential is chosen to reproduce

the known asymptotic properties of thestrong interaction. The free parameters in

these models are determined from acomparison with experimental data.

Non-relativistic potential models +Relativistic corrections + PQCD

LQCD predicts spectrum

2 0.2 s 0.3


Experimental Study of Charmonium

e+e- annihilation• Direct formation only possible for

JPC = 1-- states.

• All other states must be produced via radiative decays of the vector states, or via two-photon processes, ISR, B-decay, double charmonium.

Good mass and width resolution for

the vector states. For the other states

modest resolutions (detector-limited).

In general, the measurement of In general, the measurement of

sub-MeV widths not possible in esub-MeV widths not possible in e++ee--..

pp annihilation• Direct formation possible for all

quantum numbers.

• Excellent measurement of masses Excellent measurement of masses and widths for all states, given by and widths for all states, given by beam energy resolution and not beam energy resolution and not detector-limiteddetector-limited.


Experimental Method in pp Annihilation

4/412

22

2

2RR

RoutinBW

ME

BB

kJ

The cross section for the process: pp cc final stateis given by the Breit-Wigner formula:

The production rate is a convolution of theBW cross section and the beam energy distribution function f(E,E):

bBW EEEdEfL )(),(0

The resonance mass MR, total width R and product of branching ratiosinto the initial and final state BinBout can be extracted by measuring theformation rate for that resonance as a function of the cm energy E.


The cc spectrum

Ted Barnes


Charmonium Physics Programfrom CDR and TPR

• Below DD threshold– Measurement of C(1S) mass and total width

– Discovery/measurement of C(2S)

– hC(11P1) confirmation/measurement (mass, width, decays, ...)

– Angular distributions in the radiative decays of the C states.

• Above DD threshold– higher vector states

– (narrow) D states

– radial excitations of P states


The c(11S0) Mass and Total Width

M(c) = 2979.6 1.2 MeV/c2 (c) = 17.3 2.6 MeV


Recent Discoveries in Charmonium

• Discovery of the c(21S0) by Belle (+BaBar, CLEO).

Small splitting from . OK when

coupled channel effects included.

• Discovery of new narrow state(s) above DD threshold X(3872) at Belle (+ CDF, D0, BaBar).

M(c) = 3637.7 4.4 MeV/c2

cc

M = 3872.0 0.6 0.5 MeV/c2

2.3 MeV (90 % C.L.)

What is the X(3872) ?Charmonium 13D2 or 13D3.D0D0* molecule.Charmonium hybrid (ccg).


More New States above DD threshold

• New state discovered by Belle in the hadronic decays of the B-meson:

B K (J/) K(+-0J/)

• New state discovered by BaBar in ISR events:

e+e- Y (+-J/)

M = 3943 11 MeV/c2

= 87 22 MeV

M = 4259 8 +2-6 MeV/c2

= 88 23 +6-4 MeV

Y(3940)

Y(4260)


Charmonium States abovethe DD threshold

The energy region above the DDthreshold at 3.73 GeV is very poorlyknown. Yet this region is rich in newphysics.• The structures and the higher vector

states ((3S), (4S), (5S) ...) observed by the early e+e- experiments have not all been confirmed by the latest, much more accurate measurements by BES.

• This is the region where the first radial excitations of the singlet and triplet P states are expected to exist.

• It is in this region that the narrow D-states occur.


Observation of hc(1P1) by E835 and CLEO

E835

2/2.02.08.3525)( cMeVhM c pp hc c

CLEO

e+e- 0hc chc c chadrons

2/9.04.3524)( cMeVhM c C. Patrignani, BEACH04 presentation A. Tomaradze, QWG04 presentation

2/2.015.02.3526)(:760 cMeVhME c


Charmonium Physics Outlook

• All 8 states below threshold have been observed.– The study of the hc remains a very high priority in charmonium physics.

– The agreement between the various measurements of the c mass and width is not satisfactory. New, high-precision measurments are needed. The large value of the total width needs to be understood.

– The study of the c has just started. Small splitting from the must be understood. Width and decay modes must be measured.

– The angular distributions in the radiative decay of the triplet P states must be measured with higher accuracy.

• The energy region above open charm threshold is the most interesting for the future and will have to be explored in great detail:– find all missing states, measure their properties.

– explain nature of existing states (X(3872), Y(3940) ...)

– study radiative and strong decays, e.g. (4040)D*D* and (4160)D*D* , multi amplitude modes which can test the mechanisms of the open-charm decay.


The Competition

For the near future, new results in charmonium spectroscopy will come

from existing e+e- machines:• BES at BEPC in Beijing will collect data at the (3770) resonance• CLEO-c at Cornell will run for at least 5 years at the and

especially above threshold.• BaBar and Belle at the existing B-factories will continue to provide

first rate results in charmonium spectroscopy.


Outlook

Charmonium physics is experiencing a second youth: the experimental

and theoretical scenario changes quickly and it is difficult to predict

what the situation will be like after 2010.

Still we can look forward to a wealth of measurement which can only be

done in a precision pp experiment:• The measurement of very narrow widths, which cannot be achieved

in e+e-, e.g. the hC and the X(3872).

• The systematic study of the spectrum, below and above threshold.• The systematic study of all decay modes.


Charmonium at PANDA

• At 21032cm-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 ten times higher instantaneous luminosity.

– Better beam momentum resolution p/p = 10-5 (GSI) vs 210-4 (FNAL)

– Better detector (higher angular coverage, magnetic field, ability to detect hadronic decay modes).


Hybrids and Glueballs

The QCD spectrum is much richer than that of the quark model as the gluons can also act as hadron components.Glueballs states of pure glueHybrids qqg

Exoti

c lig

ht

qq

Exoti

c cc

1 -- 1-+

0 2000 4000MeV/c2

10-2

1

102

•Spin-exotic quantum numbers JPC are powerful signature of gluonic hadrons.•In the light meson spectrum exotic states overlap with conventional states.•In the cc meson spectrum the density of states is lower and the exotics can be resolved unambiguously.1(1400) and 1(1600) with JPC=1-+.11(2000) and h(2000) and h22(1950)(1950)

•Narrow state at 1500 MeV/c2 seen by Crystal Barrel best candidate for glueball ground state (JPC=0++).


Meson Spectrum after LEAR

( )1 4 0

( )5 4 8

'( )9 5 7

K( )4 9 51 S1

0

( )1 3 0 0

( 1 2 9 5 )

'(1 4 9 0 )

K( )1 4 6 02 S1

0

( )1 8 0 0

( )1 7 7 5

K( )1 8 3 03 S1

0

( )7 7 0

( )7 8 2

(1 0 2 0 )

K*( )8 9 21 S3

1

( )1 4 5 0

( 1 4 2 0 )

( )1 6 8 0

K*( )1 4 1 02 S3

1

a2

( )1 3 2 0

a1

( )1 2 6 0

f 2

( )1 2 7 0

f 1

( )1 2 8 5

f '2

( )1 5 2 5

K 2

( )1 4 3 0

K 1

( )1 4 0 0

b1

( )1 2 3 5

h 1( 1 1 7 0 )

h '1

( )1 3 8 0

K 1

( )1 2 7 01 P1

1

a0

( )1 4 5 0

f 0

( )1 3 7 0

f 0

( )1 7 1 0

K 0

(1 4 3 0 )1 P3

0

1 P31

1 P32

f 2

( )1 8 1 0

f '2( 2 0 4 0 )

K 2( )1 9 8 02 P3

2

2 P31

2 P30

2 P1

1

L=0 L=1

F ( )0 9 7 5

a ( )0 9 8 0

f ( )0 1 5 1 5

1 ( )1 4 0 0

1( )1 6 0 0

( )1 4 1 0

f ( )2 1 5 6 5

f ( )2 1 6 4 0

M

seen at single decayunambiguousestablished (PDG)

LEA R

notq q ? !

1 G eV / c 2

2 G eV / c 2

a1

( )1 7 0 0

a2

(1 650)

b 1( )1 7 0 0

•The LEAR Era with the experiments– @ CERN

• Asterix/Obelix

• Crystal Barrel

• Jetset/PS185

• WA102/Gams

– @ BNL• E818/E852

– @ FNAL• E760/E835

– @Serpukhov• VES/Gams

produced impressive results with high statistics and high resolution


Charmonium Hybrids

• Bag model, flux tube model constituent gluon model and LQCD.

• Three of the lowest lying cc hybrids have exotic JPC (0+-,1-+,2+-)

no mixing with nearby cc states

• Mass 4.2 – 4.5 GeV/c2.

• Charmonium hybrids expected to be much narrower than light hybrids (open charm decays forbidden or suppressed below DD** threshold).

• Cross sections for formation and production of charmonium hybrids similar to normal cc states

(~ 100 – 150 pb).

CLEO

One-gluon exchange

Excited gluon flux


Charmonium Hybrids

•Gluon rich process creates gluonic excitation in a direct way

– ccbar requires the quarks to annihilate (no rearrangement)

– yield comparable tocharmonium production

•2 complementary techniques– Production

(Fixed-Momentum)– Formation

(Broad- and Fine-Scans)

•Momentum range for a survey – p ~15 GeV

ProductionAll Quantumnumberspossible

RecoilMeson

FormationQuantumnumberslike pp


Glueballs

Detailed predictions of mass spectrum

from quenched LQCD.– Width of ground state 100 MeV– Several states predicted below 5

GeV/c2, some exotic (oddballs)– Exotic heavy glueballs:

• m(0+-) = 4140(50)(200) MeV

• m(2+-) = 4740(70)(230) MeV

• predicted narrow width

Can be either formed directly or

produced in pp annihilation.

Some predicted decay modes , ,

J/, J/ ...Morningstar und Peardon, PRD60 (1999) 034509Morningstar und Peardon, PRD56 (1997) 4043

The detection of non-exotic glueballs is not trivial, as these states mix withThe detection of non-exotic glueballs is not trivial, as these states mix withthe nearby qthe nearby qq states with the same quantum numbers, thus modifying theq states with the same quantum numbers, thus modifying theexpected decay pattern.expected decay pattern.


Hadrons in Nuclear Matter•Partial restoration of chiral symmetry in nuclear matter

– Light quarks are sensitive to quark condensate

•Evidence for mass changes of pions and kaons: – deeply bound pionic atoms– (anti)kaon yield and phase space distribution in pA

and AB collisions. •(cc) states are sensitive to gluon condensate

– small (5-10 MeV/c2) in medium modifications for low-lying (cc) (J/, c)

– significant mass shifts for excited states:

40, 100, 140 MeV/c2 for cJ, ’, (3770) resp.

•D 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)

vacuumvacuum nuclear mediumnuclear medium

K

25 MeV

100 MeV

K+

K

Hayaski, PLB 487 (2000) 96Morath, Lee, Weise, priv. Comm.

D

50 MeV

D

D+


Charmonium in Nuclei

• Measure J/ and D production cross section in p annihilation on a series of nuclear targets.

• J/ nucleus dissociation cross section

• Lowering of the D+D- mass would allow charmonium states to decay into this channel, thus resulting in a dramatic increase of width

(1D) 20 MeV 40 MeV

(2S) .28 MeV 2.7 MeV

Study relative changes of yield and width of the charmonium states.

• In medium mass reconstructed from dilepton (cc) or hadronic decays (D)


Proton Timelike Form Factors

The electromagnetic form factors of the proton in the time-like region

can be extracted from the cross section for the process:

pp e+e-

First order QED predicts:

Excellent electron identification and background rejection make this

measurement possible in PANDA. The measurement can be carried

out in parallel to the spectroscopy program and does not require any

special running.

*22

2*22

222

* cos14

cos12cos

Ep

M Gs

mG

xsc

d

d


Proton Magnetic Form Factor |GM|


Form Factor Measurement in PANDA

PANDA will be able to measure the proton timelike form factors

over the widest q2 range ever covered by a single experiment, from

threshold up to q2=20-25 GeV2, and reach the highest q2.• At low q2 (near threshold) we will be able to measure the form

factors with high statistics, measure the angular distribution (and thus GM and GE separately) and confirm the sharp rise of the FF.

• At the other end of our energy region we will be able to measure the FF at the highest values of q2 ever reached, 20-25 GeV2, which is 2 larger than the maximum value measure by E835. Since the FF decrease ~1/s5, to get comparable precision to E835 we will need ~80 times more data.

• In the E835 region we need to gain a factor of at least 10-20 in data size to be able to measure the electric and magnetic FF separately.


The Detector

• Detector Requirements:– (Nearly) 4 solid angle coverage (partial wave analysis)– High-rate capability (2×107 annihilations/s)– Good PID (, e, µ, , K, p)– Momentum resolution ( 1 %)– Vertex reconstruction for D, K0

s, – Efficient trigger– Modular design

• For Charmonium:– Pointlike interaction region– Lepton identification– Excellent calorimetry

• Energy resolution• Sensitivity to low-energy photons


Panda Detector (top view)


Panda Detector (side view)


Preliminary Sharing of Detector Responsibilities

Pellet target: GSI, FZ Jülich, TSL Uppsala, Univ. Uppsala.Cluster-jet target: GSI, Univ. Münster, INFN Genova, IMEP Vienna.Nuclear target: FZ Jülich.Micro Vertex Detector: INFN Catania, TU Dresden, Univ. Edimburgh, GSI, FZ Jülich,

Univ. Mainz, INFN Torino.Cylindrical tracker (ST/TPC): JINR Dubna, LNF, GSI, FZ Jülich, IMP Lanzhou, TU

München, INFN Pavia, Univ. Tübingen, Univ. Uppsala.Particle identification (DIRC-RICH-TOF): JINR Dubna, INFN Ferrara, Univ. Giessen,

Univ. Glasgow, GSI, FZ Jülich, IMEP Vienna.Electromagnetic calorimeter: Univ. Bochum, Univ. Giessen, GSI, KVI Groningen, FZ

Jülich, IMP Lanzhou, Univ. Mainz, Univ. Minsk, TU München, Univ. Stockholm, Univ. Uppsala, SINS Warsaw, Warsaw Univ. Of Technology.

Magnets (Solenoid, Dipole): Univ. Cracow, JINR Dubna, INFN Genova, Univ. Glasgow, IMP Lanzhou.

Muon chambers: JINR Dubna, GSI, INFN Torino.Forward Spectrometer: Univ. Cracow, IHEP Protvino, JINR Dubna.Germanium detectors: INFN Catania, INFN Torino, Univ. Mainz, KTH Stockholm.DAQ Trigger Front-end-electronics: Univ. Cracow, Univ. Giessen, GSI, FZ Jülich, Univ.

Katowice, INFN Milano, TU München, INFN Torino, SINS Warsaw.


AnnoMissioniinterne

Missioniestere

Materialidi

Consumo

MaterialeInventariabile

Totale

2006 63 237 210 245 755

2007 65 267 270 264 866

2008 69 310 405 420 1204

Piano di Spesa R&D

CSN3 Settembre 2005


Rivelatore Costo [M€] Anno

Solenoide SCDipolo (2Tm)

4.41.9

2009

Totale 6.3

Meccanica straw tubeRivelatori di vertice

Rivelatori al GeRivelatore tof a fibre

Rivelatori di muoni prot.elett.

0.30.50.5

0.150.15

Totale 1.6

Bersaglio Costruzione straw tube

Rivelatori di verticeRivelatori al Ge

Rivelatore tof a fibreRivelatori di mouni

elettronica read-out

0.20.3

0.350.550.250.7

2010

Totale 2.35

BersaglioElettronica straw tube

Rivelatori di verticeRivelatori al Ge

Rivelatore tof a fibreSistema DAQ

0.30.5

0.350.750.1

0.25

2011

Totale 2.25

Gran Totale 12.5

Piano di Spesa Costruzioni


Timeline

• 2003 (Feb 05) GSI upgrade approved by German Govmt.

PANDA part of approved project.• 2003 (March) PANDA collaboration is formed.• 2004 (Jan 15) Letter of Intent submitted.• 2004 (March) Letter of Intent approved by the QCD-PAC.• 2005 (Jan) Technical Progress Report (TPR)

submitted.• 2005 (March) Positive evaluation of TPR. R&D begins• 2006-2008 R&D.• 2009-2011 Detector Construction• 2012 Detector commissioning and start of data

taking.

Data taking lasts > 8 years


Conclusions

The HESR at the GSI FAIR facility will deliver high-qualityp beams with momenta up to 15 GeV/c (√s 5.5 GeV). This will allow Panda to carry out the followingmeasurements:• High resolution charmonium spectroscopy in formation

experiments• Study of gluonic excitations (glueballs, hybrids)• Study of hadrons in nuclear matter• Hypernuclear physics• Deeply Virtual Compton Scattering and Drell-Yan Hadron Physics has a brilliant future with PANDA at FAIR !Hadron Physics has a brilliant future with PANDA at FAIR !

Physics with the PANDA Detector at GSI Diego Bettoni Istituto Nazionale di Fisica Nucleare, Ferrara...

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