Antiproton Facilities @ Requirements for Klaus Peters KPIII/HPI, GSI Darmstadt IKF, JWGU Frankfurt p-Workshop, GSI, Darmstadt Dec 3, 2007

Antiproton Facilities @

Requirements for

Klaus PetersKPIII/HPI, GSI DarmstadtIKF, JWGU Frankfurt

p-Workshop, GSI, Darmstadt

Dec 3, 2007

2

Klaus Peters - pbar Requirements for Panda

@

HESR

PANDA

Conventional and exotic charmonium spectroscopy

Formation (scans)Production (with recoil)

Nucleon structure issuesElectromagnetic form factorsCross channel Compton scatteringDrell-Yan and others

Hyper nuclear physicsFlavored baryonsMany other topics

3


Detector

• High RatesTotal σ ~ 55 mbpeak >2·107 int/s

• Elm. Calorimetry(γ,π0,η)

• Magnetictracking

• Forward capabilities(leading particles)

• Sophisticated Trigger(s)

• Vertexing(σp,KS,Λ,…)

• Charged Particle ID(e±,μ±,π±,p,…)

4


Quark-Antiquark Binding Charmonium Physics

DD

DD*

ψ(11D2)

ψ(13D2)

ψ(13D3)

ψ(13D1)

Mcc

[G

eV

/c2]

ηc(11S0)

ηc(21S0)

J/ψ(13S1)

χc0(13P0)

χc1(13P1)

χc2(13P2)

h1c(11P1)

2.9

3.0

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

4.0D*D*

ψ(33S1)

pp [G

eV

/c]

ψ(23S1)

χc0(23P0)

χc1(23P1)

χc2(23P2)

h1c(21P1)ηc(31S0)

3.4

4.1

4.8

5.5

6.3

7.1

8.0

JP=0+ 1- 1+ (0,1,2)+ 2- (1,2,3)-

But many recent findings don‘t fit very well

5


The Potential – A Guide

SD LS SS TH V V V

2

( )3

2SV

LSc

dVdVL SV

m r dr dr

1 2 2

2

2( )

3SS Vc

S SV V r

m

2

2

2 2

ˆ ˆ2 3 112

V VT

c

S r S r S dV d VV

m r dr dr

spin-orbit(fine structure)

spin-spin(hyperfine structure)

tensor

VS and VV are the scalar and vector components of the non-relativistic potential

3

3.5

4

1 2

R/r0

V(R)/GeV

J/ψ

χc

ψ‘

Hcc

DD

Π

Σ

G. Bali et al., hep-lat/0003012

G. Bali, hep-ph/0412158

6


Z+(4433)

arXiv:0708.1790

7


X(3872) and Confirmation

hep-ex/0406022

9.4σ

11.6 σ

BABAR

Phys. Rev. Lett. 91(2003)262001152 Mill. BB

8


Mass Differences in ψππ and DDπ

• X(3872) in (ψππ) K+

Belle m=3872±0.6±0.5Babar m=3871.3±0.6±0.1

• X(3872) in (ψππ) KS

Belle m=3871.8±1.1±0.6Babar m=3868.6±1.2±1.2Γ<2.3

• X(3872) in DDπ KBelle m=3875.4±0.7+0.9

-1.6

Babar m=3875.1+0.7-0.5±0.5

Γ=3.0+1.9-1.4±0.9

mD0D0* =3871.8±0.3

mD+D-* =3879.9±0.3

E. Braaten, only D0D0* threshold considered

about 3 MeV between final states

9


Mass and Width Determination DsJ(*)(2xxx)

• Deduce mass and width from excitation function

• Many channels, but all require e-cooling at large energies

threshold Ds0*Ds0* threshold DsDs0*

possible experimental result

10


Experimental Questions - Charmonium

• Do Charmonium hybrids exist?Like 1-+ (expected to be the lightest spin-exotic state)

Are there JPC exotics in Charmonium?

• Some observed states are extremely narrow…Like X(3872), DsJ

*(2317), DsJ(2459), …

What is the real width?

• Some are observed near thresholdsLike X(3872) (DD*), Y(4260) (DsDsJ

*), …

What is the line shape, dispersive/coupled channel effects?

• There is one charged candidate– multiquark candidateZ+(4433)

Are there neutral partners? Are there more? What is the line shape? Is it a real resonance?

11


Experimental techniques - Charmonium

• Do Charmonium hybrids exist?Like 1-+ (expected to be the lightest spin-exotic state)

Are there JPC exotics in Charmonium?

• Some observed states are extremely narrow…Like X(3872), DsJ

*(2317), DsJ(2459), …

What is the real width?

• Some are observed near thresholdsLike X(3872) (DD*), Y(4260) (DsDsJ

*), …

What is the line shape, dispersive/coupled channel effects?

• There is one charged candidate – multiquark candidateZ+(4433)

Are there neutral partners? Are there more? What is the line shape? Is it a real resonance?

Charmonium production w/ light recoil particles [large pp (15 GeV/c)]

Charmonium formation[Δp ~ 30-100 keV]

Charmonium production w/ light recoil particles @ threshold (e.g. Z+π-)[pp >10 GeV/c, Δp ~ 100-200 keV]

Charmonium formation w/ anisotrop momentum steps

12


pp cross sections

PANDA

Crystal Barrel E760/E835

Obelix

PS185

Jetset http://pdg.lbl.gov/2007/hadronic-xsections/hadronicrpp_page11.pdf

CITATION: W.-M. Yao et al., J. Phys. G 33,1 (2006)

13


pp cross sections – exclusive final states

100 mb

10 mb

1 mb

100 μb

10 μb

1 μb

100 nb

10 nb

1 nb

ΛΛ

3π0

ΞΞ

ΩΩ

Ξ*Ξ

Ω*Ω

Λ*cΛc

drop of cross section due todisconnected quark lines

s dependence σ~s-X

for large phase space(e.g. 2π0 σ~s-7.2 @ χcJ)

14


pp cross sections – exclusive final states

100 mb

10 mb

1 mb

100 μb

10 μb

1 μb

100 nb

10 nb

1 nb

ηc

χc0

χc2

ηcπ0

Hybrids

Glueballs

X(3872)

Example X(3872)peak ~50 nb (E. Braaten)DDπ/ψππ ~10:1 ψππ 250 pb (ee and μμ) DDπ 500 pb (multiple channels)

includes eff. and BR

L=2·1031, duty ε=0.5∫(L*ε) = 0.86 pb-1/d 2 d/point peak (~400 ev. ψππ/~800 ev. DDπ)x 20 points 40 days

15


Experimental Method in pp Scans

( )

2in out R

BW 2 2 2R R

B B2J 14 k E M / 4

Γπσ

Γ

+=

- +

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

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

{ }0 BW bL dE f(E, E) (E)ν ε Δ σ σ= × +ò

The resonance mass MR, total width ΓR 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.

16


Exotic Charmonium Production

• Expected cross sections are O(1nb)typical channels involve DD or J/ψleptonsBR lead to small yields O(1-few %)Reconstruction ε~10-40%L=2·1032, duty ε=0.5

∫(L*ε) = 8.6 pb-1/d

• Exampleη1η [1 nb] χc1ππη l+l-7γ [10 pb incl. ε, multichannel l+l-/η]

Goal: minimum 10k for PWA 116 d or 1 fb-1

Ideal: 50k ~600 d or 5 fb-1

• Strategy1 p-year running (~200 d) at pp=15 GeV/c for a survey

additional running at optimized* (slightly lower) momentumto improve PWA sensitivity (final goal: total ~600 d, 3 p-year)

*) depending on findings

17


Hypernuclear Physics @

• Limiting factor charged particle load on central detector (0.6-1.0)·107

• L=(3-5)·1030 cm-2s-1

p re-storage <6·106

Ξ-

Secondary Target

3 GeV/c

TriggerK+K

Carbon Wire ø 10 μm

Ξ-(dss)p(uud) Λ(uds)Λ(uds)

# Neutrons

16Λ O

18Λ O

14Λ N

15Λ N

12Λ C

13Λ C

14Λ C

9ΛB

10Λ B

11Λ B

12Λ B

7ΛBe

8ΛBe

9ΛBe

10Λ Be

6ΛLi

7ΛLi

8ΛLi

9ΛLi

4ΛHe

5ΛHe

6ΛHe

7ΛHe

8ΛHe

4ΛH

3ΛH

1 2 3 4 5 6 7 8 9

4

8

7

6

3

5

2

1

10

9

# P

roto

ns

Minium 8 months full running

18


Crossed-channel Compton scattering

Cross section σ ≈ 2.5 pb @ s≈10 GeV2

L = 2·1032 cm-2s-1 → 103 Events/Month

Electromagnetic form factor of the proton (time-like)

19


pp

[GeV/c]

√s[GeV/c2]

Physics 3·10-4 10-4 3·10-5 10-5

>1.4 >2.23 ΛΛ 151 keV 51 keV 15 keV 5 keV

~2 ~2.4 Light Quarks

3.67 2.97 ηc 336 keV 112 keV 34 keV 11 keV

6.98 3.87 X(3872) 504 keV 168 keV 50 keV 17 keV

8.80 4.29 DsDs0*(2317) 574 keV 192 keV 58 keV 19 keV

15.1 5.5Charm

Production 755 keV 252 keV 77 keV 25 keV

Resolution for various Δp/p @ various pp

few 100 keV

few 100 keV

100 keV

30-100 keV

100 keV

<1 MeV

20


Resolution for various Δp/p @ various pp

10-5

10-4

3x10-4

10-3

3x10-5

2 6 10 14 GeV/c

Δp/p Lumi

1030

1031

1032

Lowest Δp/p required for charm-state scansRelaxed for detector resolution dominated cases

LightQuarks

Hyper-nuclei

NarrowCharm

NucleonStructure

ExoticCharm

21


Luminosities @ various pp

10-5

10-4

3x10-4

10-3

3x10-5

2 6 10 14 GeV/c

Δp/p Lumi

1030

1031

1032

LightQuarks

Hyper-nuclei

NarrowCharm

NucleonStructure

ExoticCharm

Highest luminosity required for exotic charm discoveriesand nucleon structure physics

detector s

aturation

22


Target considerations

• Generalfor 1011 p in HESR (circ. 574 m)2·1032 require target thickness dLOI=3.8·1015 H/cm2

• Cluster-Jet-Targetachieved 1·1015 (EU-FP6), final goal (realistic) (3-5) ·1015 (EU-FP7)if 5·1015 could be achievedthe exp. p loss during the spill could be partly compensated

• Pellet-Targetachieved 2·1015 H/cm2

main problems: pellet yield, luminosity variations(25 μm pellets, pellet has 6·1019 H/cm2)

23


@ Summary

HESR

PANDA

Maximum beam spread @ 7-10 GeV/c

should not exceed 3·10-5

ideal 1·10-5 to be safeat small and large momenta

should not exceed 3·10-4-5·10-4 respectively

Luminosities@ 7-10 GeV/c (high prec. mode)minimum 1031 ideally ~2·1031

at small momenta 1030 may be enough, but physics is limited thenat large momenta

minimum 1032 ideally >2·1032 to increase discovery potential and reasonable nucleon structure measurements

Running time≥200 d/year Detector maintainance ~3 m/year

Documents

Antiproton Facilities @ Requirements for Klaus Peters KPIII/HPI, GSI Darmstadt IKF, JWGU Frankfurt p-Workshop, GSI, Darmstadt Dec 3, 2007