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Physics with open charm mesons at. Outline: Physics foundations; Experimental techniques; Capabilities of the PANDA@FAIR; Summary. Andrey Sokolov Institute of Nuclear Physics , Research Center Jülich, Germany. The structure and dynamics of hadrons - PowerPoint PPT Presentation
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Physics with open charm mesons at
Andrey SokolovAndrey SokolovInstitute of Nuclear PhysicsInstitute of Nuclear Physics,,
Research Center Jülich, Research Center Jülich, GermanyGermany
The structure and dynamics of hadrons International Workshop XXXV on Gross Properties of Nuclei and Nuclear
Excitations, Hirschegg, Kleinwalsertal, Austria, January 14 - 20, 2007
Outline: Physics foundations; Experimental techniques; Capabilities of the PANDA@FAIR; Summary.
Andrey SokolovAndrey Sokolov 2
Panda Physics Overview Charmonium spectroscopy:
Precision M and Γ measurement: qq – potential. New states above DD threshold.
Charmed hybrids and glueballs; Interaction of charmed particles with nuclei; Hypernuclei; Further options:
Open charm physics Wide angle compton scattering; Baryon-Antibaryon production; CP-Violation (Λ,D).
Andrey SokolovAndrey Sokolov 3
Charmonium spectroscopyThe energy region above the DD threshold is very
poorly known: The higher vector states ((3S), (4S), (5S) ...)
have not all been confirmed by the latest measurements by BES.
In this region the narrow D-states are expected!!!
Andrey SokolovAndrey Sokolov 4
Charmonium Spectroscopy
M = 3872. 0 0.60.5MeV
< 2.3 MeV at 90% C.L.
by CDF
11.6 effect
A new narrow resonance called X(3872) was observed in 2003:
X(3872) 10 effect
’J/
by BELLE
The other states Y(3940), Y(4260), X(3943), Z(3934), ψ(4320) have been observed in recent years
Andrey SokolovAndrey Sokolov 5
DsJ
(2458)
Open Charm Spectroscopy
0 1 0 1 2 3
Ds
Ds*
DsJ*
(2317)
Ds1
m [G
eV/c
2 ]
D0K
D*KDs2
*
JP
}j=3/2}j=1/2
In Heavy-Light systems like H-atom; ordered by property
of the light quark; approximate j
degeneracy; the large gap between
j=3/2 and j=1/2 was unexpected.
j=L+sL
J=j+sH
in 2003 BaBar and CLEO observed two new narrow Ds mesons with surprisingly low masses.
The Ds± Spectrum
|cs> + c.c. was not expected to reveal any surprises, but…
Andrey SokolovAndrey Sokolov 6
(cs) – A Heavy-Light System
Andrey SokolovAndrey Sokolov 7
e+e- interactions: Only 1-- states are directly formed; Other states require:
ISR; B meson decays; higher order process
(γγ fusion).
pp reactions: All meson states directly formed
(very good mass resolution) other states can be studied using
production mechanism.
Production mechanism
} low cross-section, mass resolution determined by detector performance
EC
M
Andrey SokolovAndrey Sokolov 8
Energy dependency of cross section for HH
Effect of finite momentum spread
Andrey SokolovAndrey Sokolov 9
Benchmark Channels Analysis
Following reaction were chosen to demonstrate the physics performance of the PANDA detector:
..)3770( _ ccpp KDD
KKDDDDD
or
pp__0
00** ,)4040(
..)2317()2317( _00** ccpp KKDDDD sssJsJ ..)2460()2460( _ ccpp KKDDDD sssJsJ
Andrey SokolovAndrey Sokolov 10
Production cross-section
The production cross-section was estimated using the Breit-Wigner formula:
,)]/)(2[1)(4(
)(4)(
2242
2
RRp
outin
R cMscs
BBcs
m
,104.8/)/())3770(( 6
)3770(/
Jin
ppJBppBB
,107.3.).)3770(( 3 ccKDDBBout
..)3770( _ ccpp KDD
as a result the maximum total cross-section is: ,5.27 pbR
and the signal to background ratio is: 10
2
11
101.6105.41075.2
)()(
Xpp
signal
Andrey SokolovAndrey Sokolov 11
Proposed PANDA Detector
beam
Andrey SokolovAndrey Sokolov 12
Micro-Vertex Detector Displaced vertices of open charm and strangeness
with precision ~ 70 μm; Build on ATLAS experience with hybrid detectors; Silicon pixel (2-4 layers) and strips (2 layers); ~7.2 million barrel pixels, ~2 million forward pixels; R&D:
Requirements on pixel size and orientation; Investigate photon conversions; Electronics.
Andrey SokolovAndrey Sokolov 13
400mm
300m
m
Micro-Vertex Detector
Andrey SokolovAndrey Sokolov 14
Simulation of ψ(3770) Selection criteria:
Kaon ID (only by DIRC and RICH); D-meson invariant mass; D-meson secondary vertex fit; Kinematical constrain on ψ(3770) mass; Missing mass selection (Invariant mass resolution σ=10MeV).
Single D-meson reconstruction efficiency - 26%; ψ(3770) reconstruction efficiency - 4.2%; Background suppression factor - 2×109; Signal/background ratio ~ 3.
Andrey SokolovAndrey Sokolov 15
Reconstruction of D and Ds
mesonsDecay Br, [%] Efficiency, [%]
9.2 26
3.8 25
7.5 8
4.4 ~28*
KD0
KD0
KKDs
KD
* Only one kaon identification is required.
Andrey SokolovAndrey Sokolov 16
Total Reconstruction Efficiency
Reaction Efficiency, [%]
4.2
3.6
0.92
4.6*
3.3*
* Only one kaon identification is required.
..)3770( _ ccpp KDD
DDDDpp 00**)4040(
)2317()2317( **
DD sJsJpp
)2460()2460( DD sJsJpp
Andrey SokolovAndrey Sokolov 17
Summary
There are many open questions for open charm and charmonium above the DD threshold.
The PANDA detector will perform high resolution spectroscopy with p-beam and provide new data on this topic.
The Micro-Vertex Detector was designed for the reliable detection of D-mesons and its decay products.
Simulation results demonstrate the good reconstruction efficiency for D-mesons.
Very high background suppression is achieved.
Andrey SokolovAndrey Sokolov 18
Panda Participating Institutes more than 300 physicists (48 institutes) from 15 countries:
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
Andrey SokolovAndrey Sokolov 19
New Charmonium Resonances X(3872), Belle 09’2003, 1++, χc1´ or D0D* molecule
decays into J/ψπ+π-, J/ψπ+π-π0, J/ψγ, D0D*
Y(3940), Belle 09’2004, JP+, 23P1 or Hybrid?? decays into J/ψω
Y(4260), BaBar 06’2005, 1--, 23D1 (BaBar) or 43S1 (CLEO) or Hybrid decays into e+e-, J/ψπ+π-, J/ψπ0π0, J/ψK+K-
X(3943), Belle 07’2005, 0-+, ηc´´ decays into D0D*
Z(3934), Belle 07’2005, 2++, χc2´ decays into γγ, DD
ψ(4320), BaBar 06’2006, ?, Hybrid
Andrey SokolovAndrey Sokolov 20
Threshold Measurement
at threshold:
far above threshold:
ratio depends only on , M, and s
p p X X :_ _
A. Gillitzer
Andrey SokolovAndrey Sokolov 21
Facility for Antiproton and Ion Research
HESR
100 m
Andrey SokolovAndrey Sokolov 22
from RESR
High Energy Storage Ring
Storage ring for p: Np = 5×1010, Pbeam= 1.5-15 GeV/c;
High density target: pellet 1015 atoms/cm3, cluster jet,
wire;
High luminosity mode: Δp/p = 10-4, stochastic cooling,
L = 1032 cm-2s-1;
High precision mode: Δp/p = 3×10-5, electron cooling,
L = 1031 cm-2s-1.
Andrey SokolovAndrey Sokolov 23
1000 decays were simulated: Here D-mesons decayed at the point (0.1,0.1,0.4)mm. Kaon ID was required. Three tracks were refitted to the common vertex.
Simulation of the D-mesons
KD
Invariant mass of D - mesonVertex position
Andrey SokolovAndrey Sokolov 24
ψ(3770) Invariant Mass Resolution σ(Minv) = 10 MeV