The 19th Particles and Nuclei International Conference ...web.mit.edu/panic11/talks/thursday/PARALLEL-4C/3-1430/wurschig/… · Massachusetts Institute of Technology July 24-29, 2011,

The 19th Particles and Nuclei International Conference (PANIC11)Massachusetts Institute of Technology

July 24-29, 2011, Cambridge, USA

Thomas Würschig

on behalf of the PANDA collaboration

Charm spectroscopy at the

PANDA experiment

Thomas Würschig, Charm spectroscopy at PANDA, PANIC 2011 - 2 -

Introduction

Particle

physics

Hadron

physics

Nuclear

physics

Questions:

Hadronization:

Mechanism of quark confinement?

Inner structure of hadrons?

Macroscopic properties of hadrons:

Origin of mass and spin?

Existence of other colour neutral objects?

Running coupling

constant in transition region:

Long distance features of QCD?

1015 m

• PANDA (AntiProton Annihilations at Darmstadt)

Hadron physics experiment:

Study of strong interactions


Introduction

• PANDA (AntiProton Annihilations at Darmstadt)• PANDA (AntiProton Annihilations at Darmstadt

Broad physics program ...

Structural analysis of nucleons

Hypernuclei physics

In-medium effects of hadrons

Hadron spectroscopy

Focus on the charm quark sector

Baryons

q c

D mesons

c c

Charmonium

Mesons

Conventional QCD states

Multi-quark systems?Glueballs? Hybrids?

Search for exotic states


Nucl. Instr. Meth. A 561 (2006) 305–309

• Future facility

PANDA at FAIR


Stochastic cooling

Stochastic cooling

Injection

Electroncooler

IJMPE 18

No.2(2009)429• High Energy Storage Ring (HESR)

Up to 1011 stored antiprotons

Beam momentum: (1.5 ... 15) GeV/c

Fixed internal target

Frozen hydrogen or

heavier nuclear targets

Operation modes

a) High luminosity: L = 2 · 1032 cm-2 s-1 p/p 10-4

b) High resolution: L = 1031 cm-2 s-1 p/p 4 · 10-5

PANDA at FAIR


Stochastic cooling

Stochastic cooling

Injection

Electroncooler

IJMPE 18

No.2(2009)429• High Energy Storage Ring (HESR)

Operation modes

a) High luminosity: L = 2 · 1032 cm-2 s-1 p/p 10-4

b) High resolution: L = 1031 cm-2 s-1 p/p 4 · 10-5

PANDA at FAIR

Beam-target interaction:

20 million annihilations / s

Quasi continuous

time distribution of events


arXiv:0903.3905v1 [hep-ex]

Physics performance

report:

PANDA at FAIR

High charm

production

rates, e.g.:

107 D pairs

per year

1011 J /

per year

High resolution

mode off by

factor of ten only...

• Mass range


PANDA at FAIR

Fully exclusive

measurements with a

flexible trigger

Key features :

D+

+

+K

-

c = 312 μm

D±S

c = 150 μm

c = 120 μm

D0

Vertex resolution 100 m

Momentum resolution 1%

• Detector setup

4 coverage

Detection of charged

and neutral particles

Anti-

proton

beam Target

Spectrometer

Forward

Spectrometer

SolenoidDipole

Target

material

Extension along beam pipe: 14 m

Maximum height: 8 m


• Detector setup

4 coverage

Detection of charged

and neutral particles

PANDA at FAIR

Fully exclusive

measurements with a

flexible trigger

Key features :

Vertex resolution 100 m

Momentum resolution 1%

Photon detection 1 MeV ... 10 GeV

Particle identification: , e, , , p

Energy resolution (E) /E 1.5%/E

Anti-

proton

beam Target

Spectrometer

Forward

Spectrometer

SolenoidDipole

Target

material

Extension along beam pipe: 14 m

Maximum height: 8 m


Charm spectroscopy

Discovery

Confirmation

High-precision dataMass

WidthQuantum

numbers

Partial

widths

Decay pattern


• High-precision data in formation experiments

Charm spectroscopy

Fine-tuned energy scan in relevant mass region necessary

... On the market: BESIII only: e+e collider limited to JPC = 1

PANDA will allow formation experiments for any JPC


Charmonium sector c c

Charm spectroscopy

• Experimental status

Below threshold

All states established

No high-precision data

for spin-singlets


Charmonium sectorc c

Charm spectroscopy

• Experimental status

Above threshold:

Incomplete picture,

no high-precision data

Only four states

confirmed, all JPC = 1

Many predicted states

not yet observed

Discovery of new states Discrepancies with

conventional models

Established:

X(3872) and Y(4260)

... but not clearly assigned

XYZ puzzle …


Charm spectroscopy

q c

D mesons• Experimental status:

Ground states: High-precision data

Excited states: Few experimental data

Incomplete picture


Physics simulation

• Radiative decay hc c

Fully exclusive reconstruction

Resonance scan (10 data points 5 days)

Achievable resolution well below 1 MeV (current upper limit)

hc c3 hc c

Expected event rate:(High luminosity mode)

20 / day 92 / day

Signal-to-background ratio:

(Efficiency)

> 87

8%

8

25%N

events

10

20

30

40

50

3.523 3.524 3.525 3.526 3.527 3.528 3.529E [GeV]

= 0.5 MeV

hc c 5 day scan



d0

• production @ (3770)

Reconstruction:

Conservative estimate

Physics simulation

6 orders of magnitude lower

Signal

Efficiency:

40%



Physics simulation

Full phase space coverage, isotropic reconstruction

Good recovery of the D* resonance

A. Pitka, Diploma thesis

• Dalitz plot analysis Center-of mass energy 900 MeV above threshold

Charged decay modes for D mesons

Secondary vertex resolution i 100 m


• Inclusive study

Reconstruction:

identification via missing mass

Excitation function around threshold

40 events / days = 4287.6 MeV

s / MeV

# reco

‘dsi

gnal

s

Achievable resolution:

Particle width 100 keV

Mass shift 0.1 MeV/c2

4 days

per

scan point

Current

PDG values

< 3.8 MeV

M = 0.6 MeV/c2

Physics simulation

M. Mertens, PhD thesis


Physics simulation

• Resonance scan for the X(3872)

Exclusive reconstruction

Achievable resolution for particle width 100 keV

Current upper limit: 2.3 MeV

Study of line shape accessible

Counts

20

40

60

80

100

120

140

3.8714 3.8716 3.8718 3.872 3.8722 3.8724 3.8726

Nominal Center of Mass Energy for Scanpoint [GeV]

in = 100 keV

reco = 110 keV

M. Galuska, Master thesis

20 scan points

2 days / point

200 reconstructed events / day


Summary

• Charm spectroscopy Interesting domain to study QCD at hadronic length scale

Many open questions within observed spectrum

Current experimental status insufficient to solve these problems

• High-precision spectroscopy at PANDA Complementary studies to existing charm experiments

Unique tool to access states of any quantum number

High luminosityOptimized

detector setup

High beam

quality

High statistics High resolutionHighly efficient

reconstruction


Summary

U BaselIHEP BeijingU BochumIIT BombayU BonnIFIN-HH BucharestU & INFN BresciaU & INFN CataniaJU CracowTU CracowIFJ PAN CracowGSI DarmstadtTU DresdenJINR Dubna

(LIT,LPP,VBLHE)U EdinburghU ErlangenNWU Evanston

U & INFN FerraraU FrankfurtLNF-INFN FrascatiU & INFN GenovaU GlasgowU GießenKVI GroningenIKP Jülich I + IIU KatowiceIMP LanzhouU LundU MainzU MinskITEP MoscowMPEI MoscowTU MünchenU MünsterBINP Novosibirsk

IPN OrsayU & INFN PaviaIHEP ProtvinoPNPI GatchinaU of SilesiaU StockholmKTH StockholmU & INFN TorinoPolitechnico di TorinoU & INFN TriesteU TübingenTSL UppsalaU UppsalaU ValenciaSMI ViennaSINS WarsawTU Warsaw

More than 400 physicists from 53 institutions in 16 countries


Backup slides


Charmonium sector c cq c

D mesons

u

d

s

q =

Charm spectroscopy


• High-precision data in formation ... with antiprotons!

Charm spectroscopy


Charmonium


Introduction

• - Detection concept

Hermetic detector with modular sub-systems

Measurement of charged and neutral particles

Good particle identification and momentum resolution

Tracking

Central trackers

Forward trackers

Particle

identification

Čerenkov detectors

(DIRC, RICH)

TOF systems

Muon system

Electromagnetic

calorimeter (EMC)

Four-momentum

reconstruction

Tracking system:

Particle momentum

Muon system+EMC:

Particle energy

Documents

The 19th Particles and Nuclei International Conference ...web.mit.edu/panic11/talks/thursday/PARALLEL-4C/3-1430/wurschig/… · Massachusetts Institute of Technology July 24-29, 2011,