Presentation is loading. Please wait.

Presentation is loading. Please wait.

1. The Physics Case 2. Present Status 3. Hypersystems in pp Interactions 4. The Experiment Future Experiments on Hypernuclei and Hyperatoms _.

Similar presentations


Presentation on theme: "1. The Physics Case 2. Present Status 3. Hypersystems in pp Interactions 4. The Experiment Future Experiments on Hypernuclei and Hyperatoms _."— Presentation transcript:

1 1. The Physics Case 2. Present Status 3. Hypersystems in pp Interactions 4. The Experiment Future Experiments on Hypernuclei and Hyperatoms _

2 1. The Physics Case

3 baryons tagged with a strange quark as a probe of the nuclear structure nuclei as a femto-laboratory for strange baryons Two Sides of a Coin mesonic decay of hypernuclei mesonic decay of hypernuclei w  N  suppressed by Pauli blocking p F 270MeV/c w  N  p N 100MeV/c free  decay non-mesonic decay of hypernuclei non-mesonic decay of hypernuclei w  N  s N N To use nuclei as a QCD-laboratory we have to understand the laboratory

4 s=1: -, -hypernuclei nuclear structure, new symmetries the presence of a hyperon may modify the size, shape... of nuclei new specific symmetries Y-N interaction strange baryons in nuclei weak decay s=2: -atoms, -, -hypernuclei nuclear structure baryon-baryon interaction in SU(3) f H-dibaryon s=3: -atom, (-,-, -hypernuclei ?) quadrupole moment of the  Hypernuclei provide a link between nuclear physics and QCD Strange Baryons in Nuclear Systems W su  du sd  dd meson vs. gluon/quark exchange

5 Weak baryon-baryon interaction non-mesonic weak decay of hypernuclei explore the baryon-baryon weak interaction N-N scattering w N N    s N N w  N    s N N S=0 S=1 NN N only parity violating part of weak interaction parity-conserving part masked by strong interaction only parity violating part of weak interaction parity-conserving part masked by strong interaction parity violating and parity- conserving part of weak, strangeness changing, interaction q~400 MeV/c  probes short distances parity violating and parity- conserving part of weak, strangeness changing, interaction q~400 MeV/c  probes short distances

6 T. Sakai, K. Shimizu, K. Yazaki Prog.Theor.Phys.Suppl. 137 (2000) H -Particle R.L. Jaffe (1977)   free coalescence  t ~ s   nuclear breeder  t ~ s neutron stars  Nuclei as Femto-Laboratory

7 H-particle in a nucleus  free H (see e.g. T. Yamada, NP A691 (2001) 250c; (3q)+(3q) quark cluster model ) free H-dibaryon H-dibaryon in B  =12.2 MeV B  =24.0 MeV S=-2 Nuclei and H-dibaryon States Formation of an H-particle in nuclei may modify levels in -nuclei

8 Contributions to intrinsic quadrupole moment of baryons One-gluon exchange Meson exchange J=1/2 baryons have no spectroscopic quadrupole moment  - Baryon: J=3/2 long mean lifetime 0.82· s only one-gluon contributions to quadrupole moment (A.J. Buchmann Z. Naturforsch. 52 (1997) ) s s s Fundamental Properties of Baryons The  quadrupole moment is an unique testcase for the quark-quark interaction

9 hyperfine splitting in -atom  electric quadrupole moment of  prediction Q  = ( ) fm 2 E(n=11, l=10  n=10, l=9) ~ 515 keV E Q ~ few keV for Pb spin-orbit  E ls ~ (  Z) 4 l·m  quadrupole  E Q ~ (  Z) 4 Q  m 3  spin-orbit  E ls ~ (  Z) 4 l·m  quadrupole  E Q ~ (  Z) 4 Q  m 3  Q  = fm 2 Q  = fm 2 A very Strange Atom R.M. Sternheimer, M. Goldhaber PRA 8, 2207 (1973)

10 2. Present Status

11 strangeness deposition (stopped K -, - ) tagged kaon „beam“ low momentum (T=16MeV) low background also (stopped K -, + )  neutron rich nuclei strangeness production ( +, K + ) ( -, K 0 )  BNL, KEK, (GSI?) p BEAM  1 GeV/c high beam intensity low cross section (1-10 mb/sr) q > 300 MeV/c  large p, L strangeness exchange (K _,   )(K _,   ) BNL, KEK, J-PARC low beam intensity larger cross section (100 mb/sr) magic momentum  low p, L (e,e´K + ), (,K + ) TJNAF, MAMI-C spin-flip amplitude  unnatural parity states new nuclei (p  : 10  Be) polarised beam sub-MeV resolution possible (0.3 MeV) for particle unstable states   substitutional state   non-substitutional state Single Hypernuclei

12 Tamura et al. Neutron number Proton number Status of Single Hypernuclei high resolution - spectroscopy with germanium detectors B(E2)~R 4  shrinkage of 6 Li core by ~20% high resolution -spectroscopy is crucial to understand the structure of hypernculei KEK, BNL

13 Multi-Hypernuclei are terra incognita, but they exist ! 1963: Danysz et al.  10 Be 1966: Prowse  6 He 1991: KEK-E176  13 B (or  10 Be) 2001: AGS-E906  4 H (~15); no binding energies 2001: KEK-E373  6 He (Nagara) “  10 Be (Demachi-Yanagi) NAGARA H. Takahashi et al., PRL 87, (2001) Double Hypernuclei

14 Interpreting B  as  bond energy one has to consider e.g. dynamical change of the core nucleus N spin-spin interaction for non-zero spin of core excited states possible if- or intermediate -nuclei are produced in excited states Q-value difficult to determine (particularly for heavy nuclei) nuclear fragments difficult to identify with usual emulsion technique new concept required  -spectroscopy! What is known? same event

15 3. Hypersystems in pp Interactions _

16   -atoms: x-rays conversion  - (dss) p(uud)  (uds) (uds) Q = 28 MeV Conversion probability approximatly 5-10% Y. Hirata, J. Randrup et al.,  - capture

17  _ (Kaidalov & Volkovitsky) quark-gluon string model s u d s d d s d s s s s    00 Use pp Interaction to produce a hyperon “beam” (t~ s) which is tagged by the antihyperon or its decay products _ General Idea

18  - capture:  - p   + 28 MeV -- 3 GeV/c Kaons _    trigger p _ 2. Slowing down and capture of   in secondary target nucleus 2. Slowing down and capture of   in secondary target nucleus 1. Hyperon- antihyperon production at threshold 1. Hyperon- antihyperon production at threshold +23MeV  3.  -spectroskopy with Ge-detectors 3.  -spectroskopy with Ge-detectors  Production of Double Hypernuclei

19 20000 stopped  - K - beam, diamond target neutron detector arrays ( --, 12 C)  12 B + n BNL-AGS E885 few tens 2 decays of 4  H K - beam lineCylindrical Detector System 2 decays BNL-AGS E906 Captured  - per day beam/ targetdevicereactionfacility several hundreds stopped  - (K -,K + )emulsion (K -,K + ) KEK-PS E373 vertex detector + spectrometer vertex detector spectrometer,  =30 msr device 3000 „golden events“ ~ KK trigger (incl. trigger) L =2·10 32, thin target, production vertex  decay vertex p p   GSI-HESR stopped p per sec p p  K * K * K * N  K cold anti- protons <70008·10 6 /sec 5 cm 12 C (K -,K + ) JHF statusbeam/ targetreactionexperiment Competition ¯  ¯ ¯ ¯ ¯ ¯

20 Expected Count Rate - Ingredients (golden events) luminosity 2·10 32 cm -2 s -1  +  - cross section 2mb for pp  700 Hz p( MeV/c) p 500   + reconstruction probability 0.5 stopping and capture probability p CAP  0.20 total captured  -  3000 / day  - to nucleus conversion probability p   0.05 total  hyper nucleus production  4500 / month gamma emission/event, p   0.5 -ray peak efficiency p GE  0.1 ~7/day „golden“ -ray events ( + trigger) ~ 700/day with KK trigger high resolution -spectroscopy of double hypernuclei will be feasible

21  - capture:  - p   + 28 MeV -- 5.5 GeV/c Kaons _    trigger p _ 2. Slow down and capture of   in secondary target nucleus 2. Slow down and capture of   in secondary target nucleus 1. Hyperon- antihyperon production at threshold 1. Hyperon- antihyperon production at threshold +203MeV  3.  -spectroskopy with Ge-detectors 3.  -spectroskopy with Ge-detectors Production of -Atoms

22  atoms by  produktion (~35/sec) hyperfine splitting in -atom  electric quadrupole moment of  prediction Q  = ( ) fm 2 E(n=11, l=10  n=10, l=9) ~ 515 keV E Q ~ few keV for Pb taking production rate, stopping probability, capture probability and detection probability into account we expect - spin-orbit  E ls ~ (  Z) 4 l·m  quadrupole  E Q ~ (  Z) 4 Q  m 3  spin-orbit  E ls ~ (  Z) 4 l·m  quadrupole  E Q ~ (  Z) 4 Q  m 3  Q  = fm 2 Q  = fm 2 ~10 detected -transitions per day with high resolution -spectroscopy feasible A very strange Atom R.M. Sternheimer, M. Goldhaber PRA 8, 2207 (1973) Count rate estimate needs more detailed studies!

23 4. The Experiment

24 The PANDA Detector hermetic (4) high rate PID (, e, , , K, p) trigger (e, , K, D, ) compact (€) modular Elektronenkühler Injektion Kicker Septum Solid state-micro-tracker thickness ~ 3 cm High rate germanium detector

25 Summary Hypersystems provide a link between nuclear physics and QCD They allow to study basic properties of strongly interacting systems These unique experiments will be feasible at the GSI-HESR


Download ppt "1. The Physics Case 2. Present Status 3. Hypersystems in pp Interactions 4. The Experiment Future Experiments on Hypernuclei and Hyperatoms _."

Similar presentations


Ads by Google