1. PROBING STRONG INTERACTION WITH SIDDHARTA-2
SMI – STEFAN MEYER INSTITUTE
PROBING STRONG INTERACTION WITH SIDDHARTA-2
Johann Zmeskal
for the SIDDHARTA-2 Collaboration
QNP2018
Nov , 2018
Tsukuba, Ibaraki, Japan

2. SIDDHARTA-2 Collaboration
SIlicon Drift Detector for Hadronic Atom Research by Timing Applications
LNF- INFN, Frascati, Italy
SMI- ÖAW, Vienna, Austria
Politecnico di Milano, Italy
RIKEN, Japan
Univ. Tokyo, Japan
ELPH, Tohoku University, Japan
TUM, Munich, Germany
Victoria Univ., Canada
Univ. Zagreb, Croatia
Helmholtz Inst. Mainz, Germany
Univ. Jagiellonian Krakow, Poland
CERN, Switzerland
IFIN – HH, Bucharest, Romania
STRONG2020
QNP2018, Tsukuba

3. DANE – low energy charged kaons Scientific Motivation
SMI – STEFAN MEYER INSTITUTE
CONTENT
DANE – low energy charged kaons
Scientific Motivation
SIDDHARTA results
SIDDHARTA-2 setup
QNP2018, Tsukuba

4. Low energy charged kaons at DANE
e+-e-
collider
LINAC
Accu. IR
DANE principle
operates at the centre-of-mass energy of the  meson
mass m = ± .008 MeV
width  = 4.43 ± 0.06 MeV
 produced via e+e- collision with
(e+e- → ) ~ 5 µb
  production rate 2.5 x 103 s-1
→ monochromatic kaon beam (127 MeV/c)
QNP2018, Tsukuba

5. Motivation exotic hadronic atoms are bound by the Coulomb force
e.g. +-, -p, -d, Kp, Kd, …
Bohr radii >> as the typical scale of strong interaction
observable effects of QCD
energy shift  from pure Coulomb value
decay width
access to scattering at zero energy
these scattering lengths are sensitive to chiral and isospin symmetry breaking in QCD
can be analysed systematically in the framework of low-energy Effective Field Theory
QNP2018, Tsukuba

6. The scientific goal of SIDDHARTA-2
To perform a first (precision) measurement of kaonic deuterium X-ray transitions
observables 1s shift and width
kaonic deuterium + kaonic hydrogen
will allow to extract the antikaon-nucleon isospin
dependent scattering lengths
chiral symmetry breaking (mass problem)
EOS for neutron stars
QNP2018, Tsukuba

7. Forming “exotic” atoms
“normal” hydrogen
“exotic” (kaonic) hydrogen K-
X-ray
n=2
n~25
n=1
n=1 p e- K-
2p → 1s
K transition
QNP2018, Tsukuba

8. X-ray transitions to the 1s state
QNP2018, Tsukuba

9. Scattering lengths
Deser-type relation connects shift 1s and width 1s to the real and imaginary part of ɑ K-p
(µC reduced mass of the Kp system,  fine-structure constant)
U.-G. Meißner, U.Raha, A.Rusetsky, Eur. phys. J. C35 (2004) 349
next-to-leading order, including isospin breaking

10. SIDDHARTA K-p result ε1s = -283 ± 36(stat) ± 6(syst) eV
QNP2018, Tsukuba

11. Improved constraints on chiral SU(3) dynamics from kaonic hydrogen [Y
Improved constraints on chiral SU(3) dynamics from kaonic hydrogen [Y. Ikeda, T. Hyodo and W. Weise, PLB 706 (2011) 63]
Real part (left) and imaginary part (right) of the Kp  K p forward scattering amplitude extrapolated to the subthreshold region, deduced from the SIDDHARTA kaonic hydrogen measurement.
QNP2018, Tsukuba

12. SIDDHARTA-2
QNP2018, Tsukuba

13. veto-2 anti-coincidence
SIDDHARTA-2 data taking scheme
K+K- pairs produced
at DANE
triple coincidence
veto-2 anti-coincidence
SDDs
degrader
Scintillators
data taking scheme
veto-2
QNP2018, Tsukuba

14. SIDDHART-2 new X-ray detector
SDD technology with
CUBE preamplifier
55Fe spectrum
123.0 eV FWHM
CUBE
QNP2018, Tsukuba

15. SIDDHARTA-2 lightweight target cell + SDDs
Target cooling:
1 Leybold MD10 – K
target cell will be cooled via ultra
pure aluminum bars to 30 K
max. pressure 0.3 MPa
ultra pure
Al bars
Target cell wall is made of 75 µm Kapton
QNP2018, Tsukuba

16. Cryogenic target – SDDs – veto-2 arrangement
Cryo-target
QNP2018, Tsukuba

17. SIDDHARTA-2 Kd X-ray spectrum (MC simulation)
INPUT
achievable precision:
shift: 30 eV
width: 75 eV
signal: shift eV
width 800 eV
density: 5% (LHD)
detector area: 246 cm2
K yield: 0.1 %
with the yield ratio
as in Kp
S/B ~ 1 : 4
Khigh
QED K K
QNP2018, Tsukuba

18. Physical Review C96 (2017)
arXiv: v1 [nucl-th] 19 May 2017
QNP2018, Tsukuba

19. Theory – SIDDHARTA-2
width [eV]
shift [eV]
QNP2018, Tsukuba

20. Summary
First kaonic deuterium measurement will allow to determine the antikon-nucleon isospin dependent scattering lengths
SIDDHARTA-2 apparatus ready
Data taking will start mid of 2019
QNP2018, Tsukuba

21. Thank you very much for your attention!
QNP2018, Tsukuba

22. Low-energy KN interaction
Chiral perturbation theory
developed for p,  not applicable for KN systems
non-perturbative
coupled channels
approach based on
chiral SU(3) dynamics
appropriate framework to analyse the anti-kaon-nucleon system at low energy
In light exotic hadronic atoms the Bohr radius is still much larger than the typical range of strong interaction formulated in QCD, and the average momentum of the bound hadron is very small. Chiral perturbation theory (ChPT) [20–22], with symmetries and symmetry breaking patterns of QCD included, is an appropriate framework to analyse the dynamics of hadrons at low energy and to describe the observable effects in the spectrum of exotic hadronic atoms.
There are non-perturbative coupled-channel techniques based on the driving terms of the chiral effective Lagrangian which generate the (1405) dynamically as a Kbar-N quasi-bound state and as a resonance in the pi-Sigma channel. They have proved useful and successful.
High precision K- p threshold data set important constraints for such theoretical approaches.
QNP2018, Tsukuba