Yongseok Oh Kyungpook National University

Transcription

1 Yongseok Oh Kyungpook National University JLAB Theory Seminar Jan. 24, 2011

2 Basic science institute and KoRIA project Higher spin resonances in photoproduction processes 1. Introduction 2. Formalism for higher spin resonances 3. Effective Lagrangian and coupling constants 4. Application 5. Summary (Σ * photoproduction and Ξ photoproduction) P. 2

3 0 3

4 Motivation Brain drain Foreign students in the US universities (as of 2008) India: ~ 103,000 students China: ~ 98,000 students Korea: ~ 75,000 students (still increasing) Return to Korea after getting Ph.D degree 2003: ~ 2, : ~ 1,300 (decreasing) A survey of 100 young Korean scientists in the US (Are you willing to return to Korea?) No (33%) Yes (30%) Don t know (27%) No answer (10%) 4

5 Crisis of science & technology in Korea High school student s preference in S&T Medical doctor (e.g. plastic surgeons) Average score of entrance exam of Seoul National Univ. Before 2000: physics ~ medical school >> math education Now: medical school >> math education > physics National labs in Korea Crucial role in the development of Korean economy Korea research council for fundamental sciences and technology Supported by the Ministry of Education, Science and Technology 13 institutions: atomic energy, standards & science, nuclear fusion, BT, NT, etc Korea research council for industrial sciences and technology Supported by the Ministry of Knowledge-based Economics 13 institutions: IT, materials, foods, electricity, train, NT, etc However, no national lab for pure sciences (cf. KIAS) lack of large scale research facilities P. 5

6 Science Business Belt project Construction of a science city (Inter-)national labs. (BSI): ~2,000 researchers Large scale research facilities Knowledge-based business center Budget: ~3.2 billion US $ for the first 7 yrs (assumed US $1 = 1,100 KRW) New environment for R&D in pure sciences Good payroll Enough research fund Freedom in research topics (but with responsibility for the output) Large scale research facilities E.g.: Accelerators At present, only one accelerator in Korea a photon source at Pohang Plan: Rare Isotope Accelerator KoRIA: Korea Rare Isotope Accelerator The law for SBB has passed the parliament at Dec (But the details are yet to be discussed.) P. 6

7 Science Business Belt: construction of a new city The core should be Basic Science Institute. Organization of BSI (tentative) Board of directors President Committee of Group Leaders Committees Research Center Administration Center Research Units (~50) Departments P. 7

8 Scale Eventually ~50 research units ~ 2,000 Ph.Ds and ~ 2,000 Graduate Students Research Units Research fields: the WHOLE area in pure sciences Locate in the BSI campus or in other universities International manpower open to ALL nationalities (researchers and Group Leaders) Group leaders: selected by international committees Non-Korean researchers: > 30% (required) The budget of each unit: 5M ~ 10M / year in the US $ (in principle, no overhead) Execution of the budget (including the payroll): by the group leader Sunset system E.g. 5 yrs + 5 yrs Will be closed for the next research topics P. 8

9 Korea Rare Isotope Accelerator Multipurpose, heavy-ion accelerator for basic science research Nuclear physics & nuclear astrophysics & atomic physics Material science Bio and medical science Nuclear data production Nuclear fusion The first large scale research facility for pure science in Korea Proposed construction budget : 460 B Won (~ $450M) ~$90M for experimental instruments + ~ $360M for accelerator Site purchasing & payroll from a separate budget Schedule (plan) Design and R&D: 2009 ~ 2012 Construction: 2012 ~ 2016 No sunset system P. 9

10 Nuclear science is entering a new era of discovery in understanding how nature works at the most basic level and in applying that knowledge in useful ways. - National Academy 2007 RISAC Report - Symmetry studies with Fr Super heavy element Known nuclei (yellow) Stable nuclei (black) Origin of heavy elements Fission limits rapid n-capture process (r-process) Number of proton Large neutron excess Limit of nuclear stability? Double Magic 132 Sn Weakening of shell structure P. 10 Number of neutron

11 KoRIA layout SC ECR IS RFQ In-Flight Fragmentation linac SCL SCL 200MeV/u (U) Future plan H 2 + D+ Stripper ISOL linac Cyclotron K ~ 100 ISOL target In-flight target µ, Medical research SCL RFQ Low energy experiments Charge Breeder Atom trap experiment Fragment Separator linac Beam line [for acceleration] Beam line [for experiment] Target building Experiment building

12 IAC: chaired by R. E. Tribble (TAMU) TRC: chaired by J. Nolen (Argonne) You are welcome to join us! Theory group P. 12 Nuclear matter Nuclear structure

13 I With T.-S.H. Lee and K. Nakayama 13

14 Missing resonance puzzle At a mass region > 1.8 GeV many high spin states N and Δresonances as well as hyperons j

15 From V. Burkert JLab

16 Testing hadron models (such as quark models) Data analyses: coupled-channels method extract coupling constants of interaction Lagrangian Quark models give predictions on the decay (amplitudes) Decay widths cannot fix the sign of the coupling constant (sign ambiguity) work with decay amplitudes need for the relationship between coupling constants and the predicted decay amplitudes P. 16

17 II 17

18 18

19 The form of " Rushbrooke, PR 143 (66 ) Behrends and Fronsdal, PR 106 (57 ) Chang, PR 161 (67 ) Λ ± : spin projection operator of spin -1/2 (for fermion) =1 (for boson) The general expressions For integer spin n β 1 β n (n, p) = 1 n! Δ α1 α n for even n with (n a ) r = 1 2 r 2 P(α ),P(β ) n i=1 θ α i n β i + a 1 θ α1 α 2 θ β 1β 2 β θ i α i + i=3 n! 1 r!(n 2r)! (2n 1)(2n 3)(2n 2r +1) Similar expressions for odd n and for half-integer spin P. 19

20 Explicit expressions for several cases Spin-1 Spin-1/2 Spin-2 Spin-3/2 Straightforward to get the expressions for higher spin propagators P. 20

21 III 21

22 P. 22

23 J P = 1 2 ± case L 1/ 2 = g πnr N iλγ (±) π J P = 3 2 ± case 1 λ Γ (±) M R ± M µ µ π R + H.c. N L 3 / 2 = g πnr M π J P = 5 2 ± case NΓ ( ) µ πr µ + H.c. L 5 / 2 = i g πnr M π 2 NΓ(±) µ ν πr µν + H.c. J P = 7 2 ± case L 7 / 2 = g πnr M π 3 NΓ( ) µ ν α πr µνα + H.c. P

24 The general expression for the decay widths Γ(R Nπ) = 3g 2 πnr 4π 2 n (n!) 2 n(2n)! k π 2n 1 M R M π 2(n 1) ( E N ± M N ) for ( 1) n P s = ±1 with P s being the parity of the spin - s resonance R Examples Γ 1 2 Γ 3 2 Γ 5 2 Γ 7 2 ± ± ± ± Nπ = 3g 2 πnr 4π Nπ = g 2 πnr 4π Nπ = g 2 πnr 4π Nπ = g 2 πnr 4π k π M R k π 3 M R M π ( E N M N ) k π 5 M R M π 4 k π 7 M R M π 6 ( E N ± M N ) ( E N M N ) ( E N ± M N ) Isospin factor 3 is included. P. 24

25 J P = 1 2 ± case L 1/ 2 = 1 N g 2M 3 ± Γ (±) µ 2 iγ (±) N M R M µ V µ g 1 Γ (±) σ µν ν V µ R + H.c. N J P = 3 2 ± L 3 / 2 = i J P = 5 2 L 5 / 2 = J P = 7 2 L 7 / 2 = ± case g 1 2M N NΓ ν (±) V µν R µ case g 1 (2M N ) NΓ ( ) 2 ν α V µν R µα ± case ig 1 (2M N ) NΓ (±) 3 ν α β V µν R µαβ + g 2 (2M N ) 2 ν NΓ(±) V µν R µ + g 3 (2M N ) 4 NΓ(±) α β ν V µν R µαβ + H.c. ig 2 (2M N ) 3 ν NΓ( ) α V µν R µα + g 2 (2M N ) 4 ν NΓ (±) α β V µν R µαβ g 3 (2M N ) 2 NΓ(±) ν V µν R µ + H.c. ig 3 (2M N ) 3 NΓ( ) α ν V µν R µα + H.c. P. 25

26 Similar to RNV interaction But with g 3 = 0 Helicity amplitudes P. 26

27 J ± Lagrangian Decay widths P. 27

28 Decay amplitude For Quark model predictions on G(l) For 1 2 G s can be related to cc + For 3 2 and so on P. 28

29 IV 29

30 The reaction of γn KΣ * Considered resonances P. 30

31 P. 31

32 γn KKΞ + exchanged diagrams q 1 q 2 Nakayama, YO, Haberzettl, PRC 74 P. 32 This work

33 CLAS, PRC 76 (2007) Nakayama, YO, Haberzettl, PRC 74 This work P. 33

34 V 34

35 Inclusion of higher spin resonances To-do To understand the mechanism of photoproduction processes To search for the missing resonances To test various hadron models in the market Matching the coupling constants to models for hadron structure A complete list for the relationship between the CC and the decay amplitudes (of hadron models) Off-shell parameters Etc THANK YOU! 35