On the possibility of producing and measuring the spin and parity of the Θ + using slow extraction beam at AGS / BNL

Transcription

1 Penta-Quark 2003 Worksho Jefferson Lab, Newort News, Virginia November 6-8, 2003 On the ossibility of roucing an measuring the sin an arity of the Θ using slow extraction beam at AGS / BNL E. Piasetzky, D. Ashery R. E. Chrien, P. Pile Tel Aviv University BNL

2 Two Boy Reactions k Θ k Θ π π Θ k -

3 Why these Two Boy Reactions? Large rouction cross sections relative to these for electromagnetic rocesses. W. Liu an C.M. Ko : ~1 mb Photorouction: less than 100 nb 1:10 4 The current worl ata base: ~ 200 events. CLASS / TJNAF new arove roosal: 800 events / 400 Hr. Hall A, to be roose : 100 events / ay. At BNL 1 mb rouction yiel: hunres of events er hour.

4 Why these Two Boy Reactions (cont.)? A measurement of a single article momentum (ion or roton) etermines the mass of the theta. k Θ k Θ

5 Why these Two Boy Reactions (cont.)? A clear signal ue to the two boy kinematical correlation between the rouction angle an momentum. The roton momentum [GeV/c] Simulation with: 1 mb k Θ 30 mb k k n P k = 450 MeV/c The roton etection angle [eg.]

6 Why these Two Boy Reactions (cont)? The arity an sin of the theta can be etermine by the angular istribution of the outgoing etecte article.

7 k Θ Intrinsic arity: - (?) L = I - I f i Must be o if the initial an final states have oosite arity. L =1, 3, 5... k Θ Sin: 0 1 1/2 (?) 1/ = 1 2 2,0 θ = 1 L = 2 1

8 k Θ π Intrinsic arity: - (?) - L = I - I f i Must be even if the initial an final states have same arity. L = 0, k 2, 4... Θ π Sin: 0 1/2 1/2 (?) 0 1/2 1/2 θ = 1/2 L = 0

9 qr R=1fm Why these Two Boy Reactions (cont)? L = I - I f i etermine the angular istribution. The arity an sin of the theta can be etermine by the angular istribution of the outgoing etecte article. Plane wave aroximation J 0 2 (qr) J 1 2 (qr)

10 What incient momentum to choose? k k Θ Θ π Threshol for extra ion threshol rouction (k n π x) [MeV/c] [MeV/c] π Θ k At 600 MeV/c the θ s are rouce at rest. Maximize the rouction cross section. Allow searation from QE events. Enough energy to the outgoing articles. Angular istribution range sensitive to the theta quantum numbers.

11 AGS Exerimental Area Oct 03 E962, µ g-2 E952, ν mass OR FY2004 Physics Program- Possible (last run in FY2002) Nothing Planne in FY 2004 D6 * V-Target V1, π µ Beam Line U Line D6-E930, Λ Hyernuclei - Ge Ball E961, ΛΛ Hyernuclei (CDS) E964, ΛΛ Systems (Emulsion-Counters) U- E963, Proton Ra; P945C (NNSA) RHIC Transfer Line OR C4 D-Target * C-Target C4-LESBIII (2001-3) E949, K π νν E927, K e3 ; E953, hyeron sect; * A-Target B-Target ** B -Target * * A3 RSVP MECO E940, µ N en (NSF 2006 construction start) A3 - NASA Raiobiology (Fe) C -Target A3-E951, µµ Collier Targetry P965, etetor test B5 RSVP K0PI0 E926, K L0 π 0 νν (NSF 2006 construction start) OR C6/8-LESBII (being ecommissione)

12 D6 Beam Line, 25 GeV/c rotons on 9 cm t 1.00E08 Maximum Momentum:1900 MeV/c 2 Stage Searation, 3 r orer otics, secial collimators Length: 31.6 meters Kaons/10 TP 25 GeV/c rotons y = 3E-13x E07 y = 1E-15x E E E E E Kaon Momentum (MeV/c) K- actual excet 0.45 & 0.6 GeV/c (est) K (estimate) Power (K- actual excet 0.45 & 0.6 GeV/c (est)) Power (K (estimate))

13 Maximum Momentum: 830 MeV/c 2 Stage Searation, 3 r orer otics, secial collimators Length: 19.6 meters K - flux er 6 x 10 13, 25 GeV/c rotons on 6 cm Pt target Particle Momentum Flux K 800 MeV/c 3.0 x 10 7 K stoing 6.0 x 10 6

14 Summary: We roose a secon generation exeriment that can rovie a strong signal of the theta an information on the sin an arity of the state. Large rouction cross sections relative to these for electromagnetic rocesses. A measurement of a single article momentum (ion or roton) etermines the mass of the theta. A clear signal ue to the two boy kinematical correlation between the rouction angle an momentum. The arity an sin of the theta can be etermine by the angular istribution of the outgoing etecte article.

15 AGS/BNL is a natural lace to exloit the Θ Beam lines an target are available A sectrometer is available for the D6 beam line, one coul be configure for the LESBIII beam line No major equiment eveloment is necessary As far as equiment an manower is concern, these measurements can be one in early 2004 in the D6 beam line, some work require to be able to use LESBIII Problem: to get BNL / DOE to suort an AGS fixe target exeriment Anticiate buget roblems are severe in FY There are 11 AGS fixe target NP an HEP exeriments on the books with little hoe of running Only an excetional strong suort from a large community for a measurement with a very comelling hysics otential might lea to ositive resonse

16 The en

17 Why these Two Boy Reactions (cont)? L = I - I f i etermine the angular istribution. The arity an sin of the theta can be etermine by the angular istribution of the outgoing etecte article. u u u u s n K For a irect icku reaction (,)? u u s Θ J 0 2 (qr) J 1 2 (qr) qr R=1fm

18 k Θ u s K u u s u u θ

19 k Θ π u s K u π u θ u u s

20 K -->Θ Momentum Transfer to Θ (MeV/c) threshol 0 eg roton 6 eg roton 12 eg roton Kaon Momentum (MeV/c)

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25 J 0 2 (qr) J 1 2 (qr) qr R=1fm

26 D6 Beam Line, 25 GeV/c rotons on 9 cm t 1.00E08 Kaons/10 TP 25 GeV/c rotons 1.00E E E E E03 y = 3E-13x y = 1E-15x E Kaon Momentum (MeV/c) K- actual excet 0.45 & 0.6 GeV/c (est) K (estimate) Power (K- actual excet 0.45 & 0.6 GeV/c (est)) Power (K (estimate))

27 Why these Two Boy Reactions? Large rouction cross sections relative to these for electromagnetic rocesses. W. Liu an C.M. Ko : ~1 mb Photorouction: less than 100 nb 1:10 4 A measurement of a single article momentum (ion or roton) etermines the mass of the theta. A clear signal ue to the two boy kinematical correlation between the rouction angle an momentum. The arity an sin of the theta can be etermine by the angular istribution of the outgoing etecte article.

28 AGS erformance PROTON BEAM FY96 FY97 FY98/99 FY2000 FY2001 FY2002 SEB SEB FEB (g-2) SEB FEB (g-2) FEB (g-2) FEB (g-2) SEB Beam Energy 24 GeV 24 GeV 24 GeV 24 GeV 24 GeV 24 GeV 24 GeV 24 GeV Peak Beam Intensity 62 x x x x x x x x Total rotons accelerate 0.9 x x x x x x x x Sill Length/Cycle Time 1.6 sec/3.6 sec 1.6 sec/3.6 sec 2.8 sec/5.1 sec 2.4 sec/5.4 sec -> Duty Cycle 44% 44% 55% 44% Sill Structure Moulation (eak-average) /average 20% 20% 20% 20% Average Availability /Best Week 76% / 92% 71% / 79% 58 % / 67 % 71% / 88% 55 % / 83 % 74 % / 87 % 83 % / 88 % 85 % / 97 % HEAVY ION BEAM Au Au Fe (NASA) Au Fe (NASA) Fe (NASA) Fe (NASA) Fe (NASA) Beam Energy /nucleon 11 / 4 / 2 GeV 11 / 8 / 6 GeV 1.0 / 0.6 GeV 11 GeV 1.0 / 0.6 GeV 1.0 GeV 1.0 GeV 1.0 GeV Peak Beam Intensity 4 x 10 8 Au/ 17 x 10 8 Au/ 20 x 10 8 Fe/ 9 x 10 8 Au/bunch 36 x 10 8 Fe/ 17 x 10 8 Fe/ 80 x 10 8 Fe/ 49 x 10 8 Fe/ Sill Length/Cycle Time 1.4 sec/3.6 sec 1.5 sec/4.0 sec 1.2 sec/3.0 sec 0.9 sec/3.3 sec 0.9 sec/3.3 sec 0.9 sec/3.3 sec -> Duty Cycle 39% 38% 40 % 27% 27% 27% Sill Structure Moulation (eak-average) /average <20% <20% <20% <20% <20% <20% Average Availability 80% 82 % 96 % 81 % 90 % 90 % 97 % 84 %

29 Proerties of D6 2GeV Beam Line Maximum Momentum:1900 MeV/c 2 Stage Searation, 3 r orer otics, secial collimators Length: 31.6 meters Particle flux* er 3 x 10 13, 25 GeV/c rotons on 9 cm Pt target Particle Momentum Flux Beam Purity K MeV/c 8.0 x % K MeV/c 3.0 x % K MeV/c 1.1 x % K MeV/c 3.8 x % 1800 MeV/c 3.6 x % 1400 MeV/c 1.2 x % * Proton flux in D-line limite by beam loss consierations, u to 7.6 x rotons/ags cycle have been extracte.

30 Proerties of C4 LESBIII Beam Line Maximum Momentum: 830 MeV/c 2 Stage Searation, 3 r orer otics, secial collimators Length: 19.6 meters K - flux er 6 x 10 13, 25 GeV/c rotons on 6 cm Pt target Particle Momentum Flux Beam Purity K 800 MeV/c 3.0 x % K stoing 6.0 x 10 6

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32 u s u u u K u u s θ For a irect icku reaction (,) n