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Heavy X- hyperatoms
at PANDA
Marcell Steinen – on behalf of the PANDA Collaboration
In collaboration with E. Friedman
THEIA Workshop, Speyer, 27.11.2019
Helmholtz-Institut Mainz
This project has received funding from the European Union's Horizon 2020
research and innovation programme under grant agreement No. 824093.
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X--nucleus interaction
2
K. Nakazawa et al.,
PTEP (2015) 033D02
PastKEK E224
BNL E885
Present J-PARC E07 J-PARC E05STAR
ALICEJ-PARC E07
FutureJ-PARC E70
J-PARC E03
PANDA
Talk: A. Mathis
S. Acharya et al. Phys.
Rev. Lett. 123, 112002
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Topics
• The PANDA experiment at FAIR
• Strangeness nuclear physics at PANDA
• X- 208Pb hyperatom experiment at PANDA
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FAIR
4
PANDA
APPACBM
NuSTAR
Facility for Antiproton and Ion Research
Speyer
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FAIR - under construction
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https://www.gsi.de/forschungbeschleuniger/fair/bau_von_fair/bilder_und_videos.htm
SIS 100 Ring – Sep./Oct. 2019
Concrete: 8 x Frankfurt stadium
Steel: 9 x Eiffel Tower
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HESR
SIS 100/300
SIS18
RESR/CR
30 GeV Protons70 MeV
p-Linac
p production target
PANDA
PANDA at FAIR
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PANDA situated in High Energy Storage Ring
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HESR
• Modularized start version
– 1010 p stored
– Luminosity up to 2x1031 cm-2 s-1
– pp = 1.5 – 15 GeV/c
– Dp/p ≤ 5x10-5
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Physics pillars of PANDA
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Strange baryon spectroscopy
Hyperon production & pol.
Hyperon transition form factors
Strangeness in pp
Hadrons in nuclei
Hyperon-nucleus dynamics
Hypernuclei and Hyperatoms
Nuclear physics
Spectroscopy
Hidden/open-charm states
Gluon-rich QCD states
Light-meson systems
Nucleon structure
Generalized parton distributions
Drell Yan process
Time-like form factors
Bound states
and dynamics
of QCD
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PANDA as hyperon factory
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Production rates: LL ~1000 /s
@ 2 MHz pp X-X+ ~100 /s
T. Johansson, AIP Conf. Proc. Of LEAP 2003, p. 96
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Strangeness nuclear physics
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Sanchez Lorente et al., Physics
Letters B 749 (2015), pp. 421-424
Pochodzalla et al., Nuclear
Physics A 954 (2016) 323–34
See talk by
J. Pochodzalla
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PANDA schedule
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Day-One
0.5 fb-1
1 fb-1
>10 fb-1
Phase-0
p @ HESR
L in 20Ne
Hyperatoms
Hypernuclei
Talk by
J. Messchendorp
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PANDA detector
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Hypernuclear/atom setup not shown
• Almost 4π
• Avg. 20 MHz
• Software trigger
• High res. tracking + PID
• Vertex reconstr. for e.g.
D, K0S, hyperons
• PWO calorimeter
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Production of hyperatoms/nuclei
• Primary target
– Production of X-
pN -> X-X+/0
• Secondary target
– Stopping of X-
– Atomic cascade of X-
– Nuclear conversion
X- + p -> LL + 28 MeV
• PANGEA
– X-Ray spectroscopy of
heavy X- hyperatoms (0.1 - 1 MeV)
– g spectroscopy of
light LL hypernuclei (0.1 - 10 MeV)
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X-
LL
g
X-ray
p- p-
hyperatoms
hypernuclei
p
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Hypernuclear/atom setup
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• Dedicated target system
• PANGEA
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Target system
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Primary target
20 mm
p
Secondary target
Hyperatom208Pb
Hypernuclei11B+Tracker
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Primary target - Prototype
• 2D positioning system
– Several targets
– Steerable for constant
luminosity
– Small
– UHV compatible, magnetic
field and radiation hard
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Carbon filament (r ~3µm)
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Secondary target optimization
• Optimization of absorber shape
– Maximize X- stopping
– Minimize X-ray
absorption
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Based on events generated in GiBUU
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PANda GErmanium Array
● Collaboration with NuSTAR (DEGAS)
● 20 triple HPGe detectors
● Full energy efficiency ~5 % @ 60Co
● Electro-mechanical cooling (~LN2 temp.)
● BGO veto
● Fully integrated design
18 3 x HV/Preamp
DCS
CrystalsBGO veto
Support electronics 12 cm
Cold head/
Cooler
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PANGEA: Cooling
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• Improved thermal insulation
• X-Cooler II/III too weak
Courtesy of I. Kojouharov
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PANGEA - Prototype
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Courtesy of I. Kojouharov
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PANGEA: First spectrum
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0 2000 4000 6000 8000
0
2000
4000
6000co
un
ts
Ch.
Test of HEX82, 2700 V
5000 5200 5400 5600 5800 6000
0
1000
2000
3000
4000
5000
6000
co
un
ts
Ch.
Courtesy of I. Kojouharov
Too high temperatures
prevented fully biasing!Flying assembly with
prototype of preamplifier
FWHM: 2.8 keV (60Co)
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X-ray spectroscopy of X-- hyperatoms
X-ray spectroscopy of X--
hyperatoms
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Observables
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Energy shift ΔEn0nuc
and width Γn0abs
γ1
γ2
(n0)
(n0+2)
(n0+1)
Nuclear
absorption
Yγ2 =𝑁𝛾2 ٿ 𝛾1
𝑁𝛾1 ٿ 𝛾0
=𝚪𝐧𝟎+𝟏𝐚𝐛𝐬
𝜞𝒏𝟎+𝟏𝒂𝒃𝒔 +Γn0+1
em
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X--nucleus potential
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Simplified assumption:
𝑈 𝑟 ∝ 1 +𝜇
𝑀𝑏0 𝜌𝑛 𝑟 + 𝜌𝑝 𝑟
𝜌𝑛,𝑝 𝑟 = 𝜌𝑛,𝑝0
1
1 + exp𝑟 − 𝑐𝑛,𝑝𝑎𝑛,𝑝
𝑏0 = 0.25 + 𝑖0.04𝑎𝑛 = 𝑎𝑝𝑐𝑛,𝑝 fixed by 𝑅𝑝,𝑟𝑚𝑠 and n skin
𝜌𝑛,𝑝0 from N and Z
Schematic calculations to explore experimental sensitivity.
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X- - 208Pb
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Calculations performed with code provided by E. Friedman
1.8 keV
1.3 keV
56 %
208Pb
(9,8)
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Possible targets
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Calculations performed with code provided by E. Friedman
FWHMGe(558 keV) ~ 1,4 keV
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Systematic uncertainties
• Neutron skin Δnp in 208Pb well-established
• Present uncertainty of Δnp -> Systematic uncertainty in observables
• 𝛅 𝜟𝑬 𝟏𝟎,𝟗 → 𝟗,𝟖𝒏𝒖𝒄
𝐬𝐲𝐬~ ± 100 eV
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n s
kin
thic
knes
sΔnp
[fm
]
Centelles et al., Phys.Rev.Lett. 102 (2009) 122502
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Full simulation
• Signals after cuts and efficiencies 1237
– 180 days at 2 MHz pC
• 𝛅 𝜟𝑬 𝟏𝟎,𝟗 → 𝟗,𝟖𝒏𝒖𝒄
𝒔𝒕𝒂𝒕= ± 140 eV
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Estimation of VΞ
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𝛅(𝐑𝐞 𝐕𝚵 )𝐬𝐭𝐚𝐭 ≈ 𝛅(𝐈𝐦 𝐕𝚵 )𝐬𝐭𝐚𝐭 ≈ 𝟏𝐌𝐞𝐕
𝑏0 = 0.25 + 𝑖0.04
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Complementary experiments
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J-PARC E07: X--C hyperatoms not included
See talk before lunch
K. Tanida
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Timeline
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Take-home message
• PANDA@FAIR is a versatile experiment with a
broad physics program
• Strangeness nuclear physics is an important pillar of
PANDA
• Heavy hyperatoms unique for PANDA, complementary
to J-PARC E03/07
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Backup Slides
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Stopping of secondary X-
6/17/2019 34
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FEP-efficiency PANGEA
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HPGe irradiation test
• Irradiation test at COSY with single crystal prototype
• 5.5 days COSY
→ 96 days PANDA
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Results
• DAQ and therm. issues
decrease performance
• PSA allows partial
resolution recovery
• Annealing recovers initial
crystal performance
→ Detector withstands
irradiation
• New systematic test:
TRIGA reactor (2019/20)
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