“Relativistic Nuclear Physics and Quantum Chromodynamics” XXII International Baldin Seminar on High Energy Physics Problems
15th - 20th September 2014
JINR - Dubna (RUSSIA)
The PANDA Project @ FAIR
Marco Maggiora on behalf of the PANDA Collaboration
Department of Physics and INFN – Turin, Italy
Primary Beams
•1012/s; 1.5 GeV/u; 238U28+
•Factor 100-1000 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 (0) - 30 GeV
Storage and Cooler Rings
•Radioactive beams
•e – A collider
•1011 stored and cooled 0.8 - 14.5 GeV antiprotons
•Cooled beams
•Rapidly cycling superconducting magnets
Key Technical Features
Facility for Antiproton
and Ion Research
The future FAIR facility
15-20 Sep 2014 ISHEPP2014 2
High luminosity mode
High resolution mode
• dp/p ~ 10-5 (electron cooling)
• Lumin. = 1031 cm-2 s-1
• Lumin. = 2 x 1032 cm-2 s-1
• dp/p ~ 10-4 (stochastic cooling)
• Production rate 2x107/sec
• Pbeam = 1 - 15 GeV/c
• Nstored = 5x1010 p
• Internal Target
_
p
HESR - High Energy Storage Ring
Internal Target Detector
2.3 ≤ √s ≤ 5.5 GeV
15-20 Sep 2014 ISHEPP2014 3
AMU Aligarh, Basel, Beijing, BITS Pillani, Bochum, IIT Bombay, Bonn, Brescia, IFIN Bucharest, IIT Chicago, AGH-
UST Cracow, JGU Cracow, IFJ PAN Cracow, Cracow UT, Edinburgh, Erlangen, Ferrara, Frankfurt, Gauhati,
Genova, Giessen, Glasgow, GSI, FZ Jülich, JINR Dubna, Katowice, KVIGroningen, Lanzhou, Legnaro, LNF, Lund,
Mainz, Minsk, ITEP Moscow, MPEI Moscow, TU München, Münster, BARC Mumbai, Northwestern, BINP
Novosibirsk, IPN Orsay, Pavia, IHEP Protvino, PNPI St.Petersburg, South Gujarat University, SVNIT Surat, Sadar
Patel University, KTH Stockholm, Stockholm, FH Südwestfalen, Suranaree University of Technology, Sydney, Dep.
A. Avogadro Torino, Dep. Fis. Sperimentale Torino, Torino Politecnico, Trieste, TSL Uppsala, Tübingen, Uppsala,
Valencia, NCBJ Warsaw, TU Warsaw, AAS Wien
At present 520 physicists from 67 institutions in 17 countries
The Collaboration
15-20 Sep 2014 ISHEPP2014 4
_ P
pp: Pellet or Cluster target
pA: wire target
_ _
Target Spectrometer
Solenoid magnet for high pt tracks:
Superconducting coil & iron return yoke
(B=2T)
Forward Spectrometer
Dipole magnet for forward tracks
(2T.m)
PANDA spectrometer
Physics Performance Report for PANDA arXiv:0903.3905 [hep-ex]
PANDA Magnet TDR http://www-panda.gsi.de/archive/public/P_magn_TDR.pdf
15-20 Sep 2014 ISHEPP2014 5
• Requirements
– Proton Target
– 5 x 1015 cm-2 for
maximum luminosity
• Pellet Target
– Frozen droplets 20m
– also possible: D2, N2, Ne, ...
– Status: 5 x 1015
• Cluster Jet Target
– Dense gas jet
– also D2, N2, Ne, ...
– Status: 8 x 1014
Cluster beam after nozzle
-10 0 10 20 -20 transverse position[mm]
are
al density [
a.u
.]
N2 H2
Target system
15-20 Sep 2014 ISHEPP2014 6
Physics Performance Report for PANDA arXiv:0903.3905
PANDA STT TDR arXiv:1205.5441v1 [physics.ins-det]
MVD STT
PANDA spectrometer: Tracking
Silicon MicroVertex Central Tracker GEM Detectors Drift Chambers
15-20 Sep 2014 ISHEPP2014 7
Micro Vertex Detector
• 4 barrels and 6 disks
• Inner layers:
hybrid pixels (100x100 µm2)
– 140 module, 12M channels
• Outer layers:
silicon strip detectors
– double sided strips
– 400 modules, 200k channels
• Mixed forward disks
• Continuous readout
Requirements
• c(D±) 312 m
c(Ds±) 147 m
• Vertex resolution 50 m
Silicon Microvertex Detector
15-20 Sep 2014 ISHEPP2014 8
• Design figures:
– σrφ ~ 150µm , σz ~ 1mm
– δp/p ~ 12% (with MVD)
– Material budget ~ 2% X0
2 Alternatives:
• Time Projection Chamber (phased out)
– Continuous sampling
GEMs readout plane
(Ion feedback suppression)
Online tracklet finding
• Straw Tube Tracker (selected!)
– about 4000 straws
– 27 µm thin mylar tubes, 1 cm Ø
– Stability by 1 bar overpressure
Central Tracker
15-20 Sep 2014 ISHEPP2014 9
Plastic Scintillators
PANDA spectrometer: Particle IDentification
Muon Detectors
Barrel DIRC Barrel TOF Endcap DIRC Endcap TOF
Forward RICH
Physics Performance Report for PANDA arXiv:0903.3905 [hep-ex]
15-20 Sep 2014 ISHEPP2014 10
n
Lens Focussing PANDA DIRC
• Lens focussing
• shorter radiator
• no water tank
• compact pixel readout
(CP-PMTs or APDs)
beam
DIRC
15-20 Sep 2014 ISHEPP2014 11
Inside the solenoid Barrel: 12 layers inside the yoke + 1 bi-layer
(“zero” bi-layer) in before iron
Endcap: 5 layers + “zero” bi-layer before iron
Muon Filter, outside solenoid
4 x (60mm/Fe + 30mm/MDT)
Endcap, inside solenoid
5 layers of MDT
Barrel, inside solenoid
12 layers of MDT + “zero” bi-layer
beam direction
Outside the solenoid “Muon Filter”, 4 layers
Proportional tubes : anode signal and induction signal on 1 cm strips
Muon detector
15-20 Sep 2014 ISHEPP2014 12
10 000 crystals
PANDA spectrometer: Particle IDentification
PbWO4 EMC
Forward Shashlyk EMC
Physics Performance Report for PANDA arXiv:0903.3905 [hep-ex]
PANDA EMC TDR arXiv:0810.1216v1 [physics.ins-det]
15-20 Sep 2014 ISHEPP2014 13
• PWO is dense and fast
• Increase light yield:
– improved PWO II
– operation at -25°C
• Challenges:
– temperature stable to 0.1°C
– control radiation damage
– low noise electronics
• Delivery of crystals started
Barrel Calorimeter
• 11000 PWO Crystals
• LAAPD readout, 2 x 1cm2
• σ(E)/E1.5%/√E + 1%
Forward Endcap
• 4000 PWO crystals
• High occupancy in center
• LAAPD readout
PANDA PWO Calorimeters
15-20 Sep 2014 ISHEPP2014 14
Internal C target to produce
Active silicon target to stop the and
detect the hypenuclei decay products
Germanium array detector, with 15
clusters of 3 gemanium
active target
Germanium array
Foreseeen 2 KeV energy resolution,
1.3 MeV p energy resolution
beam
Hypernuclear Detector
15-20 Sep 2014 ISHEPP2014 15
• Particle identification essential tool
• Momentum range 200 MeV/c – 10 GeV/c
• Different processes for PID needed
PID Processes
• Čerenkov radiation:
Radiators: quartz, aerogel, C4F10
• Energy loss: p < 1 GeV
Good accuracy with TPC,
Stt system dE/dx under study
• Time of flight:
needs a start detector
• Electromagnetic showers:
EMC for e and γ
dE/dx of STT
Forward ToF
PANDA PID requirements
15-20 Sep 2014 ISHEPP2014 16
Particle IDentification with PANDA
DIRC MVD
EMC
STT
PANDA PID Requirements:
particle identification essential for PANDA
momentum range 200 MeV/c – 10 GeV/c
Extreme high rates 2·107 Hz
good particle separation (K-p e-p)
different detectors needed for PID
15-20 Sep 2014 ISHEPP2014 17
Physics Performance Report for PANDA arXiv:0903.3905
0 2 4 6 8 12 15 10
p Momentum [GeV/c]
Mass [GeV/c2] 1 2 3 4 5 6
ΛΛ
ΣΣ
ΞΞ
ΛcΛc ΣcΣc ΞcΞc
ΩcΩc ΩΩ DD
DsDs
qqqq ccqq
nng,ssg ccg
ggg,gg
light qq
π,ρ,ω,f2,K,K*
cc
J/ψ, ηc, χcJ
nng,ssg ccg
ggg
baryon/antybaryon production
EM processes:
TL form factos
Drell-Yan and TMDS
GPDs
TDA
strangeness physics
hyperatoms
S=-2 nuclear system
Ξ− nuclei
ΛΛ hypernuclei
meson spectroscopy
light mesons
charmonium
exotics states
glueballs
hybrids
molecules/multiquarks
open charm
charm in nuclei
PANDA scientific program
15-20 Sep 2014 ISHEPP2014 18
E. Tomasi-Gustafsson, M.P. Rekalo, PLB 504 (2001) 291
Generator:
|GM| = 22.5 (1 + q2 / 0.71)-2 (1 + q2 / 3.6)-1
= |GE|/|GM|
lower sensitivity
@ higher q2
Time-Like EM proton form factors in p + p → e- + e+
M. Sudol et al., EPJ A44 (2010) 373
L = 2 10 32 cm-2 s-1 → 2 fb-1 in 100 days
15-20 Sep 2014 ISHEPP2014 19
R=|GE|/|GM|
L = 2 10 32 cm-2 s-1 → 2 fb-1 in 100 days
PANDA scenario: expected results
M. Sudol et al., EPJ A44 (2010) 373
BABAR: B. Aubert et al. PRD 73 (2006) 012005
PS170: G. Bardin et al., NPB 411 (1994) 3
pQCD inspired: V. A. Matveev et al., LNC 7 (1973) 719
S. J. Brodsky et al., PRL 31 (1973) 1153
VDM: F. Iachello, PLB 43 (1973) 191
Extended VDM: E.L.Lomon, PRC 66 (2002) 045501
E. A. Kuraev et al., PLB 712 (2012) 240
Individual determination of
|GE| and |GM|
up to q2 14 (GeV/c)2 !!
15-20 Sep 2014 ISHEPP2014 20
A. Dbeyssi, PhD Thesis: PANDA unofficial results
PANDA scenario: expected results
M. Sudol et al., EPJ A44 (2010) 373
L = 2 10 32 cm-2 s-1 → 2 fb-1 in 100 days
Absolute accessible
up to q2 28 (GeV/c)2
BABAR:
B. Aubert et al. PRD 73 (2006) 012005
E835:
M. Andreotti et al., PLB 559 (2003) 20
M. Ambrogiani et al., PRD 60 (1999) 032002
Fenice:
A. Antonelli et al., NPB 517 (1998) 3
PS170:
G. Bardin et al., NPB 411 (1994) 3
E760:
T. A. Armstrong et al., PRD 56 (1997) 2509
CLEO:
T. K. Pedlar et al. , PRL 95 (2005) 261803
DM1:
B. Delcourt et al., PLB 86 (1979) 395
DM2:
D. Bisello et al., NPB 224 (1983) 379
BES:
M. Ablikim et al., PLB 630 (2005) 14
15-20 Sep 2014 ISHEPP2014 21
PANDA scenario: asymptotic behaviours
E. Tomasi-Gustafsson, 12th International Conference on Nuclear Reaction Mechanisms, Villa Monastero,
Varenna, Italy, 15 - 19 Jun 2009, pp.447, arXiv:0907.4442v1 [nucl-th]
L = 2 10 32 cm-2 s-1 → 2 fb-1 in 100 days BABAR:
B. Aubert et al. PRD 73 (2006) 012005
E835:
M. Andreotti et al., PLB 559 (2003) 20
M. Ambrogiani et al., PRD 60 (1999) 032002
Fenice:
A. Antonelli et al., NPB 517 (1998) 3
PS170:
G. Bardin et al., NPB 411 (1994) 3
E760:
T. A. Armstrong et al., PRD 56 (1997) 2509
CLEO:
T. K. Pedlar et al. , PRL 95 (2005) 261803
DM1:
B. Delcourt et al., PLB 86 (1979) 395
DM2:
D. Bisello et al., NPB 224 (1983) 379
BES:
M. Ablikim et al., PLB 630 (2005) 14
Probing the Phragmèn-Lindelöf theorem:
15-20 Sep 2014 ISHEPP2014 22
TMD: κT-dependent Parton Distributions
Courtesy of Aram Kotzinian
Twist-2 PDFs:
)kx,(fkd)x(f T1T2
1
15-20 Sep 2014 ISHEPP2014 23
Leading-twist correlator depends on
five more distribution functions:
TMD: κT-dependent Parton Distributions
2
1 T 1 Tf (x ) d k f (x,k ) Twist-2 PDFs
Distribution
functions Chirality
even odd
Twist-2
U
L
T
f1
g1
,
h1,
1h
1Lh
1Th
1Tf
1Tg
TMD: κT-dependent Parton Distributions
Transversity
Boer-Mulders
Sivers
Kinematics
q2P
Mx
1
2
1
xxx 21F -
q2P
Mx
2
2
2
s
Mxxτ
2
21
Why Drell Yan? Asymmetries depend on PD only (SIDIS→convolution with QFF)
Why ?
Each valence quark can contribuite to the diagram
p
plenty of (single) spin effects
3 planes: plane to polarisation vectors
plane
plane
*γp -
*γ-
0QM 22
Drell-Yan Di-Lepton Production — pp X -
Kinematics
2
1
1
Mx
2P q
F 1 2x x x -
2
2
2
Mx
2P q
2
1 2
Mτ x x
s
Why Drell Yan? Asymmetries depend on PD only (SIDIS→convolution with QFF)
Why ?
Each valence quark can contribuite to the diagram
p
plenty of (single) spin effects
3 planes: plane to polarisation vectors
plane
plane
*p γ-
*γ -
0QM 22
Drell-Yan Di-Lepton Production — pp X -
2 22 a a a a
a 1 2 1 22 2 aF 1 2
d σ 4α π 1e f (x )f (x ) f (x )f (x )
dM dx 9M s x x
Scaling:
Full x1,x2 range .
τ 0,1
2
F
d σ 1
sd τdx
Fermilab E866 800 GeV/c
Experimental Asymmetries @ PANDA — ( )p p μ μ X -
0 2
2 2 1 12
1 1 2 1 212
1 2 1 2
1 cos sin cos2 212
aa
a a
a T T T T
a
de f f
d dx dx d Q M
h
M
h
-
T
h p h p p pk
F F
1 1 2 1 2 1 1 1 2 21 1 , , 1 2a aa a
T T T T T T Tf f d d f x f xd - p p p p k p pF
Unpolarised:
Single Spin:
2
2
2
22 2
2 22
1 2 2
2
1
1
212 2 1
1 2 2 1 2 1 2 2
1
1
1
1
1
2
1 cos sin12
sin sin
sin sin 3 4 22
a T S T
a
S T
a a
TS T T T T T T
T
a
a
T
a
a
Th h
fde
d dx dx d sQ M
M
h h
M M
f
-
-
- - - -
T
S h pk
h p
h p h p h p p p h p p
F
F
F
cos2A
2sin SA -
2sin SA
[2] 2 1 1 1DY-μμ1
Eff R 1.5 M 2.5 GeV/c 0.16 s = 0.08 s 200K Ev month 2
- - -
[1] 2
p480K ev with E 15 GeV on fixed target, 1 .5 M 2.5 GeV/c
Experimental Asymmetries @ PANDA —
p p μ μ X -
[1]A. Bianconi and M. Radici, Phys. Rev. D71 (2005) 074014 [2]Physics Performance Report for PANDA, arXiv: 0903.3905
s ~ 30 GeV2
11
a a
Tf f
1 1
a a
Th h
11
a a
Tf f
1 1
a a
Th h
1 1
a ah h
1 1
a ah h
The experimental data set available is far from being complete. All
strange hyperons and single charmed hyperons are energetically
accessible in pp collisions at PANDA.
By comparing several reactions
involving different quark flavours
the OZI rule and its possible violation, can be tested
In PANDA pp ΛΛ, ΛΞ, ΛΞ, ΞΞ , ΣΣ, ΩΩ, ΛcΛc, ΣcΣc, ΩcΩc can be produced allowing the study of the dependences on spin
observables.
QCD dynamics
_
_
15-20 Sep 2014 ISHEPP2014 30
The knowledge of Baryon-Baryon potential is essential for the
understanding of the composition of nuclear matter.
Nuclear NN forces are known, YN interaction,
thanks to hypernuclear physics, is relatively
known, but YY interaction is completely
unknown, there are just a few double Λ
hypernuclear events.
NAGARA
ΛΛ-hypernuclei, -atoms, Ω-atoms allow to have an insight to more complex nuclear systems containing strangeness (neutron stars, hyperon-stars, strange-quark stars, …)
The fraction of baryons and leptons in neutron
star matter arXiv:0801.3791v1
Baryon-baryon interaction
15-20 Sep 2014 ISHEPP2014 31
http://arxiv.org/abs/0801.3791v1
(S=±2) hyperon – antihyperon systems are fully accessible at PANDA
Double Λ Hypernucleus:
p
p
Λ
Λ n
n
2 Λ‘s replace 2 nucleons in a nucleus
p
p
-
n
n
Doubly Strange Hypernucleus:
Ξ- occupies a nuclear level
Exotic hyperatom:
p
-
e-
n p
n
Ξ- occupies an atomic level
Ξ - -nucleus interaction
• Atomic orbits overlap nucleus • Strong interaction and Coulomb force interplay • Lowest atomic levels are shifted and broadened • Potential: Coulomb + optical
Ξ -N interaction: • short range interaction • long range interaction • …..
ΛΛ strong interaction • only possible in double hypernuclei • YY potential: attractive/repulsive? • hyperfragments probability dependence on YY potential One Boson Exchange features ΛΛ ΛΛ: only non strange, I =0 meson exchange (ω,η...) ΛΛ weak interaction: hyperon induced decay:
• ΛΛ Λ n: ΓΛn
Up to now double strange systems have been produced by K- beams in the reaction:
K- (N, Ξ-) K+ (N- quasi free or bound in nucleus)
S=-2 baryon can be produced via:
Choice of the target:
free protons (hydrogen target) or protons and neutrons in a nucleus (quasi-free reactions)
Advantages of nuclear target :
a) higher cross section (scaling as ~A2/3)
b) - slowing down in dense (nuclear) matter
Disadvantages of nuclear target :
c) high background (annihilation)
d) high beam consuming (beam losses)
reaction = 2b at 3GeV/c
bar /h
Goal: maximize the “stopped Ξ-” with a suitable set-up
A new way for double strange systems
15-20 Sep 2014 ISHEPP2014 33
A new way for double strange systems
N
p
p
K
K Pbar +N - + bar : = 2 b; pbar (3GeV/c) below p production
I Target
bar +N Kbar+ Kbar +p + … [ - production tag]
Elastic scattering in nucleus:
strong slowing down (a challenge)
slowing down in matter
(with decay)
- capture into atomic levels and hyperatomic cascade
Capture into nucleus:
Strong and Coulomb forces
Xray
- N
conversion + sticking
p
N
2 MeV II Ta r ge t
decay (MWD,NMWD… )
15-20 Sep 2014 ISHEPP2014 34
Nucleus B(AZ) [MeV] B(
AZ) [MeV] Reference Reaction
10Be 17.7± 0.4 4.3±0.4 M.Danysz et al., PRL.11(1963) 29 K- + A K+ + -
6He 10.9±0.5 4.6±0.5 D.J.Prowse, PRL.17(1966) 782 K- + A K+ + -
10Be 8.5±0.7 -4.9±0.7 KEK-E176 K- + p K+ + - (q.f)
13B 27.6±0.7 4.9±0.7 S.Aoki et al., PTP.85(1991) 1287 K- + p K+ + - (q.f)
12B 4.5±0.5 P.Khaustov et al.,
PRC.61(2000)027601 (12C)atom
- 12B n
6He 7.25±0.19 1.01±0.2 KEK-E373,NAGARA H.Takahashi et
al., PRL.87(2001)212502-1 K- + p K+ + - (q.f)
12B ≈ 6-10nb K.Yamamoto et al., PLB.478(2000) 401 K- + 12C K+ + 12B
+0.18 - 0.11
+0.18 - 0.11
Status of the art:
Up to know these systems have been studied in cosmic rays or using kaon-beams: K−+ p → − + K+ From - to Double Hypernuclei
KEK, BNL-AGS, have demonstrated that the systems are produced. At JPARC with high intensity kaon-beams the goal is to stop 104 − in a nuclear target.
At PANDA the same amount of data will be collected, with the possibility to run with different nuclear targets at the same time.
ΛΛ Hypernuclei
15-20 Sep 2014 ISHEPP2014 35
3500 3520 MeV 3510 CBall e
v./
2 M
eV
100
ECM
CBall E835
1000
E 8
35 e
v./
pb
cc1
e+e- → Y’ → c1,2
→ e+e- → J/y
e+e- interactions:
- Only 1-- states are formed - Other states only by secondary decays (moderate mass resolution related to the detector)
- Most states directly formed
(very good mass resolution; p-beam
can be efficiently cooled)
→ J/y → e+e-
p p→ c1,2 _
pp reactions: _
Br(e+e- →y ·Br(y → hc) = 2.5 1-5 pp → hc) = 1.2 1
-3 Br( _
Antiproton power
15-20 Sep 2014 ISHEPP2014 36
_
Production
all JPC available
There are two mechanisms to access particular final states:
Formation
only selected JPC
Spectroscopy with antiprotons
15-20 Sep 2014 ISHEPP2014 37
p
p _
G
M
p
M
H
p _
p
M
H
p _
There are two mechanisms to access particular final states:
Even exotic quantum numbers can be reached σ ~100 pb
Production
Formation
only selected JPC
Spectroscopy with antiprotons
15-20 Sep 2014 ISHEPP2014 38
p
p _
p
p _
H
p
p _
H G
All ordinary quantum numbers can be reached σ ~1 μb
p
p _
G
M
p
M
H
p _
p
M
H
p _
Even exotic quantum numbers can be reached σ ~100 pb
Production
Formation
Spectroscopy with antiprotons
15-20 Sep 2014 ISHEPP2014 39
In the light meson spectrum exotic states overlap with conventional states
The QCD spectrum is much rich than that of the naive quark model also the gluons can act as hadron components
The “exotic hadrons” fall in 3 general categories:
(qq) g Hybrids
gg
+
Glueballs
(qq)(qq) Multiquarks
E x o
t i c l
i g h
t q
q
E x o
t i c c
c
1 -- 1 -+
0 2000 4000 MeV/ c 2
10 -2
1
10 2
Exotic hadrons
15-20 Sep 2014 ISHEPP2014 40
The QCD spectrum is much rich than that of the naive quark model also the gluons can act as hadron components
The “exotic hadrons” fall in 3 general categories:
(qq) g Hybrids
gg
+
Glueballs
(qq)(qq) Multiquarks
E x o
t i c l
i g h
t q
q
E x o
t i c c
c
1 -- 1 -+
0 2000 4000 MeV/ c 2
10 -2
1
10 2
In the cc meson spectrum the density of
states is lower and therefore so the overlap
Exotic hadrons
15-20 Sep 2014 ISHEPP2014 41
_
The B-factory experiments have discovered a large number of candidates for charmonium and
charmonium-like meson states, many of which can not be easily accommodated by theory. State
parameters are still largely unknown. Few events collected in 10 years of running
PANDA will detect 100 events per day
B-meson decay
cc
p
e+
e−
p
J/Y
Initial State Radiation
B
b
u,d
c
c
s
u,d
W−
Xcc
K(*)
X(3872) Belle, Babar, Cleo, CDF, D0
Y(3940) Belle, Babar
Y(4140)? CDF
Z(4430)
Z1(4050) Belle
Z2(4250)
1−− states
X(4008)? Belle
Y(4260) BaBar, Belle,CLEO
Y(4350) BaBar, Belle
Y(4660) Belle
e+ e+
e− e−
*
* Xcc
-collisions X(3915) Belle
Z(3930) Belle
Y(4350) Belle
Associate production
e+e−⟶J/Ψ Xcc
X(3940) Belle
X(4160) Belle e+
e−
c
c
c
c g
D(*)
D(*)
J/Ψ C+
XYZ Mesons
15-20 Sep 2014 ISHEPP2014 42
• masses are barely known; • often widths are just upper limits;
• few final states have been studied;
• statistics are poor; • quantum number assignment is possible for few states;
• some resonances need confirmation…
Without entering into the details of each state some general consideration can be drawn.
Arxiv:09010.3409v2 [hep-th]
There are problems of compatibility Theory - Experiment
Quantum numbers assignment and structure become clear only with high statistics,
different final states and very precise energy measurements,.
XYZ Mesons
15-20 Sep 2014 ISHEPP2014 43
is a convolution of the
Measured
rate
The production rate of a certain final state
CM Energy
Resonance
cross
section
BW cross section
Beam
and the beam energy distribution function f(E,E):
bBW EEEdEfL )(),(0
The resonance mass MR, total width R and product of branching ratios into the initial and final state BinBout can be extracted by measuring the formation rate for that resonance as a function of the cm energy E.
e+e−: typical mass res. ~ 10 MeV Fermilab: 240 keV
HESR: ~30 keV
Antiproton power
15-20 Sep 2014 ISHEPP2014 44
All the details of the PANDA experimental program are reported in the “Physics Performance Report”.
Within this document, we present the results of detailed simulations performed to evaluate detector performance on many benchmark channels.
arXiv:0903.3905v1
PANDA Physics Performance Report
15-20 Sep 2014 ISHEPP2014 45
on behalf of the PANDA Collaboration
THANK YOU!
15-20 Sep 2014 ISHEPP2014 46
2 2 21 dσ 3 1 ν1 λcos θ μsin θcosφ sin θcos2φσ dΩ 4π λ 3 2
NLO pQCD: λ 1, 0, υ 0
Lam-Tung sum rule: 1- λ = 2ν
• reflects the spin-½ nature of the quarks
• insensitive top QCD-corrections
Experimental data [1]: υ 30 %
[1] J.S.Conway et al., Phys. Rev. D39 (1989) 92.
Di-Lepton Rest Frame
Drell-Yan Asymmetries — Xμμpp-
Remarkable and unexpected violation of Lam-Tung rule
NA10 @ CERN λ, μ, ν measured in π N→μ+μ – X
υ involves transverse spin effects at leading twist [2]
If unpolarised DY σ is kept differential on kT , cos2φ contribution to angular distribution provide:
[2] D. Boer et al., Phys. Rev. D60 (1999) 014012.
2 2
1 2, 1 1h (x κ ) h (x ,κ )
[1] NA10 coll., Z. Phys. C37 (1988) 545
Drell-Yan Asymmetries — Xμμpp-
[1] L. Zhu et al, PRL 99 (2007) 082301; [12 D. Boer, Phys. Rew. D60 (1999) 014012.
Boer-Mulders
T-odd Chiral-odd TMD
• ν > 0 → valence h 1 has same sign in π and N
• ν(π-W→μ+μ-X) ~ h 1 (π)valence x h 1
(p)valence
• ν(pd→μ+μ-X) ~ h 1 (p)valence x h 1
(p)sea
• ν > 0 → valence and sea h 1 has same sign,
but sea h 1 should be significantly smaller
[1]
# of partons in polarized proton depends on
Sivers effect
p pS p k
Transverse Single Spin Asymmetries: correlation functions
X
pp
pS k qp
X
pp
qSk qp
partons’ polarisation in unpolarized proton depends on
Boer Mulders effect
q qS p k
-
FF
X
pq
S p
q
Polarising Fragmentation Function
qS p p
Hadrons’ polarisation coming from
unpolarised quarks depends on
X
pq
qS ppqfragmentation of polarised quark depends on
Collins effect
q qS p p
/ , / 1ˆˆ( , ) ( , ) ( , ) ( )qq p q p T
kf x f x k f x k
M
- S k S p k
, / / 1
1 1 ˆˆ( , ) ( , ) ( , ) ( )2 2q
q
q p q p q
kf x f x k h x k
M
- s k s p k
/ , / 1ˆ ˆ( , ) ( , ) ( , ) ( )
h q h q q q
h
pD z D z p H z p
z M
s p s p p
All these effects may may lead to
Single Spin Asymmetries (SSA):
d d
d dNA
-
Transverse Single Spin Asymmetries: correlation functions
X
pp
pS k qp# of partons in polarized proton depends on
Sivers effect
p pS p k
X
pp
qSk qp
partons’ polarisation in unpolarized proton depends on
Boer Mulders effect
q qS p k
-
FF
X
pq
S p
q
Polarising Fragmentation Function
qS p p
Hadrons’ polarisation coming from
unpolarised quarks depends on
X
pq
qS ppqfragmentation of polarised quark depends on
Collins effect
q qS p p
/ , / 1ˆˆ( , ) ( , ) ( , ) ( )qq p q p T
kf x f x k f x k
M
- S k S p k
, / / 1
1 1 ˆˆ( , ) ( , ) ( , ) ( )2 2q
q
q p q p q
kf x f x k h x k
M
- s k s p k
/ , / 1ˆ ˆ( , ) ( , ) ( , ) ( )
h q h q q q
h
pD z D z p H z p
z M
s p s p p
Transverse Single Spin Asymmetries: correlation functions
X
pp
pS k qp# of partons in polarized proton depends on
Sivers effect
p pS p k
X
pp
qSk qp
partons’ polarisation in unpolarized proton depends on
Boer Mulders effect
q qS p k
-
FF
X
pq
S p
q
Polarising Fragmentation Function
qS p p
Hadrons’ polarisation coming from
Unpolarised quarks depends on
X
pq
qS ppqfragmentation of polarised quark depends on
Collins effect
q qS p p
Transverse Single Spin Asymmetries in Drell-Yan
d d
d dNA
-
expected[1] to be small but not negligible
for HESR layout on fixed target
0 ≤ qT ≤ 1 GeV/c
√s = 14.14 GeV
[1] Anselmino et al., Phys. Rev. D72, 094007 (2005).
2 2 2 2
/
2
/
/
2 2 2
/
,
2 ,
,
,
q q q Tq q q p q qq
N
q q q T q p q qq q q p q
N
q qq
q
p
q
e d d q f xA
f x
e d d q f x f x
d
d
-
-
k k k k k
k k k k k k
k
1/2
, ,N qq q Tq pp
kf x k f x k
m
-
Originates from the Sivers function[1]:
Test of Universality
[2]
1 1( , ) ( , ) q q
T SIDIS T DYf x k f x k
-
[2] J.C. Collins, Phys. Lett. B536 (2002) 43
Transverse Single Spin Asymmetries in Drell-Yan
d d
d dNA
-
expected[1] to be small but not negligible
for HESR layout on fixed target
0 ≤ qT ≤ 1 GeV/c
√s = 14.14 GeV
[1] Anselmino et al., Phys. Rev. D72, 094007 (2005).
2 2 2 2
/
2
/
/
2 2 2
/
,
2 ,
,
,
q q q Tq q q p q qq
N
q q q T q p q qq q q p q
N
q qq
q
p
q
e d d q f xA
f x
e d d q f x f x
d
d
-
-
k k k k k
k k k k k k
k
Originates from the Sivers function[1]:
[2] J.C. Collins, Phys. Lett. B536 (2002) 43
Pellet or cluster-jet target
2T Superconducting solenoid for high pt particles 2Tm Dipole for forward tracks
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Silicon Microvertex detector
Central Tracker
Forward Chambers
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Barrel DIRC Barrel TOF
Endcap DIRC Forward TOF
Forward RICH
Muon Detectors
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PWO EMC Forward Shashlyk EMC Hadron Calorimeter
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