Presentation is loading. Please wait.

Presentation is loading. Please wait.

Few Nucleon Studies at TUNL 1. The Nd A y Puzzle: (a) Refinement of NN 3 P J Phase Shifts: high-precision np and pp A y measurements (b) Complete Picture.

Similar presentations


Presentation on theme: "Few Nucleon Studies at TUNL 1. The Nd A y Puzzle: (a) Refinement of NN 3 P J Phase Shifts: high-precision np and pp A y measurements (b) Complete Picture."— Presentation transcript:

1 Few Nucleon Studies at TUNL 1. The Nd A y Puzzle: (a) Refinement of NN 3 P J Phase Shifts: high-precision np and pp A y measurements (b) Complete Picture of Energy Dependence of Discrepancy: new Nd A y measurements 2. The A y Puzzle in the 4N system: measurements with polarized 3 He target 3. Discrepancies in nd Breakup: new cross-section measurements

2 Nd A y Puzzle: Refinement of 3 P J np Phase Shifts Proposal: Measurement of A y (  ) for np Elastic Scattering at 7.6 and 18.5 MeV PI: W. Tornow Participants C.R. Howell, Duke Univ. J.H. Kelley, NC State Univ. R.L. Walter, Duke Univ. A. Crowell (Postdoc) J. Deng (Graduate Student) M. Kiser (Graduate Student) R. Macri (Graduate Student/Postdoc) B.J. Crowe (NC Central University) R.S. Pedroni (NC A&T State University) G.J. Weisel, Penn State at Altoona

3 Status of Low-Energy np 3 P J Phase Shifts (1988) (1994) Experimental Details: 7.6 MeV 18.5 MeV Number data points: 15 15 Accuracy (±3%): ±0.0003 ±0.0005 Accelerator: tandem tandem Neutron Source: 2 H(d,n) 2 H(d,n) Target Area: NSSA NSSA Counting time: 120 days 40 days

4 Nd A y Puzzle: Refinement of 3 P J pp Phase Shifts Proposal: Measurement of A y (  ) for pp Elastic Scattering at 6.14 and 15.6 MeV PIs: H.J. Karwowski and E.J. Ludwig Participants T.C. Black, UNC-Wilmington T.B. Clegg, UNC-Chapel Hill M.S. Boswell (Graduate Student) T.V. Daniels (Graduate Student) B.M. Fisher (Graduate Student) D. Gupta (Postdoc) T. Katabuchi (Postdoc) D.S. Leonard (Graduate Student)

5 Status of Low-Energy pp 3 P J Phase Shifts

6 Experimental Details of pp Ay Measurements Experimental Details: 6.14 MeV 15.6 MeV Number data points: 10 10 Accuracy (±5%): ±0.00005 ±0.00005 Accelerator: tandem tandem Target Area: Gas Jet Gas Jet

7 Nd A y Puzzle: Complete Energy dependence of nd A y Discrepancy Proposal: Measurement of A y (  ) for nd Elastic Scattering at 0.65, 19.0, 28.0 and 35.0 MeV PIs: W. Tornow and G.J. Weisel (Penn State at Altoona) Participants C.R. Howell, Duke Univ. J.H. Kelley, NC State Univ. D.M. Markoff, NC State Univ. R.L. Walter, Duke Univ. A. Crowell (Postdoc) J. Deng (Graduate Student) M. Kiser (Graduate Student) R. Macri (Graduate Student/Postdoc) B.J. Crowe (NC Central University) R.S. Pedroni (NC A&T State University) H. Witała (Jagellonian Univ., Cracow, Poland) W. Glöckle (Univ. of Bochum, Bochum, Germany)

8 3NF in NNLO EFT Calculations E. Epelbaum, A. Nogga, W. Gleockle, H. Kamada, Ulf-G. Mei  ner and H. Witała, arXiv:nucl-th/0208023 v1 13 Aug 2002 3NF TPE OPEContact E n = 3 MeV 0 60120060120180

9 EFT Calculations E n = 3 MeV NLONNLO E n = 10 MeV E n = 65 MeV 060 120180060120

10 Energy Dependence of Discrepancy in Nd A y Puzzle

11 Experimental Details of LE nd A y Measurements Experimental Parameters Tandem Accelerator NTOF Target Room E n = 650 keV 7 Li(p,n) source reaction  A y = ±0.001 Counting time: 25 days

12 Experimental Details of HE nd A y Measurements Experimental Parameters Tandem Accelerator Neutron Shielded Source Area E n = 19, 28 and 35 MeV 2 H(d,n) and 3 H(d,n) source reactions  A y = ±0.005 Counting times: 40 days at 19 MeV 60 days at 28 MeV 60 days at 35 MeV

13 LE pd A y Measurements PIs: H.J. Karwowski and E.J. Ludwig Participants T.C. Black, UNC at Wilmington T.B. Clegg, UNC-Chapel Hill M.S. Boswell (Graduate Student/MS work) T.V. Daniels (Graduate Student) B.M. Fisher (Graduate Student) D. Gupta (Postdoc) T. Katabuchi (Postdoc) D.S. Leonard (Graduate Student) A. Kievsky, INFN, Sezione di Pisa M. Viviani, INFN, Sezione di Pisa Experimental Details: 650 keV 1.0 MeV Number data points: 10 10 Accuracy : ±0.0005 ±0.0005 Accelerator: tandem tandem Target Area: Gas Jet Gas Jet

14 Proposal to Measure A 0y for p 3 He Elastic-Scattering with a Polarized 3 He Target PI: T.B. Clegg Participants H.J. Karwowski, UNC-Chapel Hill E.J. Ludwig, UNC-Chapel Hill M.S. Boswell (Graduate Student) T.V. Daniels (Graduate Student/MS project) B.M. Fisher (Ph.D. thesis project) D. Gupta (Postdoc) T. Katabuchi (Postdoc) D.S. Leonard (Graduate Student) A. Kievsky, INFN, Sezione di Pisa M. Viviani, INFN, Sezione di Pisa

15 The A y Puzzle in the 4N system

16 p 3 He Elastic Scattering: Comparison of A y0 and A 0y

17 Sensitivity of p 3 He to NN 3 P J Potential

18 Verification of Selected Neutron-Deuteron Breakup Cross-Section Data PIs: C.R. Howell W. Tornow and R.L. Walter Participants A. Crowell (Postdoc) J. Deng (Ph.D. thesis project) M. Kiser (Graduate Student) R. Macri (Graduate Student/Postdoc) C. Jackson (NC A&T State University) R.S. Pedroni (NC A&T State University) B.J. Crowe (NC Central University) W. von Witsch (Univ. of Bonn) H. Witała (Jagellonian Univ., Cracow, Poland) W. Glöckle (Univ. of Bochum, Bochum, Germany)

19 1. Space Star Anomaly 2. nn FSI Main Discrepancies in nd Breakup  1 S 0 a nn 3. 0° proton energy spectrum  1 S 0 a nn (a)  - + d  n + n + p  a nn = -18.6 ± 0.3 ± 0.3 fm (PSI, 1984 and 1987 and LAMPF, 1998) (b) n +d  n + n + p TUNL: a nn = -18.6 ± 0.5 fm (1999) Bonn: a nn = -16.3 ± 0.4 fm (2000)  4. nn QFS (recent data from von Witsch’s group in Bonn) 

20 Space Star Anomaly 1.0 2.0 3.0 d 5  /d  1 d  2 dS (mb/sr 2 MeV) nd data, TUNL 1996 nd data, Erlangen Univ. 1988 pd data, Univ. Cologne 1991

21 Energy Dependence

22 Current Setup: coincidence geometry

23 Proposed Setup: recoil geometry Systematic Differences with present setup: (1) Measured cross section only depends on relative efficiency of one neutron det. (2) Only modest correction for neutron attenuation (3) Need correction for neutron loss when both neutrons are in solid angle of det. (4) Can perform simultaneous measurements of identical configurations using recoil-geometry setup with coincidence-geometry setup behind it.


Download ppt "Few Nucleon Studies at TUNL 1. The Nd A y Puzzle: (a) Refinement of NN 3 P J Phase Shifts: high-precision np and pp A y measurements (b) Complete Picture."

Similar presentations


Ads by Google