Hyperon-Proton Scattering at the J-PARC

Transcription

1 Hyeron-Proton Scattering at the J-PARC Motivation historic background YN scattering exeriment at KEK-PS... and at J-PARC Objective Method High-Seed Image Delay Tube What is it? Characteristics & Performances exected a simulation IEIRI Masaharu Miyazaki

2 Historic Background Exeriment ('32 ('47 neutron) π + - meson), n scattering ('74 (YN scattering) J/ψ) (Hyernuclei) Idea established Suort Theory ('35 meson theory) '51hard-core ('64 Quark hyothesis) OBE '77H-article QCM Insired by SU(3)f E251, E289 E452 Y@KEK E## Y@J-PARC (get the icture) NN&YN by Lattice... based on SU(2)/SU(3)f

3 Available Y scatt. Data [1] - bubble chamber era '6-'7s bubble chamber era '6-'7s NN YN Numbers of data oints in angular distributions n YN dσ/dω (+39) P a few Other obs from Arndt et al. PRD28(83)97 from Dover & Feshbach Ann.Phys.198(9)321

4 Available Y scatt. Data [2] - at 12 GeV KEK-PS at 12 GeV KEK-PS E251, E289 for dσ/dω (Σ + & ) E452 for olarization (Σ + & Λ) E251, E289 E Σ Σ elastic 4 < P Σ < 7 MeV/c E289.. Julich FSS E289 E cosθ CM

5 Baryon-Baryon otential V(r) [MeV] 1 1S S n r [fm] Σ Σ + I 3-1 Λ +1 Ξ - -2 Ξ - OBE HC, ω ρ,σ, π Paris Nijmegen Bonn-Julich QCM (λ λ)(σ σ) Eff.Meson Exch. ot. Pauli Tokyo Kyoto Tubingen Flavor SU(3)

6 Fig. 1. (Left) The radial wave function of Ξ, in 1 S (circle) and 3 S 1 (triangle) channels, obtained at t t = 6. The Green s V(r) [MeV] Baryon-Baryon otential 1S 1 2 r [fm] OBE HC, ω ρ,σ, π Paris Nijmegen Bonn-Julich QCM (λ λ)(σ σ) Eff.Meson Exch. ot. 1. Pauli Tokyo Kyoto 1.5 Tubingen Flavor SU(3) r (fm) 1S 3S G(r ",k 2 ( S )) G(r ",k 2 ( S 1 )) t!t = r [fm] FIG. 2 (color online). deendence of the NN wave function at t t 6 in the 1 S The lattice QCD result of the radial and 3 S 1 channels. Inset shows the two-dimensional view in the x y lane. beyond which we lot only the data locating on the - coor- dinate axes and their nearest neighbors. As is clear from Fig. 2, the wave function is suressed at short distance and has a slight enhancement at medium distance, which suggests that the NN system has a reulsion (attraction) at short (medium) distance. Figure 3 shows the central (effective central) NN otential in the 1 S ( 3 S 1 ) channel at t t 6. As for r 2 in Eq. (2), we take the discrete form of the Lalacian with the nearest-neighbor oints. E is obtained from the Green s function G ~r; E which is a solution of the Helmholtz equation on the lattice [9]. By fitting the wave function ~r at the oints ~r 1 16; ; and 1 16; 1; by G ~r; E, we obtain E 1 S :49 15 MeV and E 3 S 1 V C (r) [MeV] S 3 S 1 OPEP V C r g2 N g 2 N 4 ~ 1 ~ 2 ~ 1 ~ 2 3 where we have used m :53 GeV to be consistent with our data, while K the N + couling constant is used, g 2 in the quenched aroximation, the π ossible - as the connected quark exch nucleons. In addition, there is in artifact to the NN otential from the diagram (the ghost exchange) betwe Its contribution to the central otentia ~ 1 ~ 2 3 m 2m N 2 1 r m2 2m e m r. Here N couling constant and a mass a resectively. The ghost otential ha which dominates over the Yukawa tances. Its significance can be estima sign and the magnitude of e m r V C large distances, because V C r has tween 1 S and 3 S 1. Our resent data the ghost at large distances within indicate g N g N. Several comments are in order her wave function at low energy (E! asy r sin kr k V C (r) [MeV] 6 4 kr! r a r r=.fm, where r=.14fm r r [fm] r=.69fm -4 FIG. 3 (colorξ online). The lattice QCD result of the central (effective central) art of the NN otential V C r [VC eff r ] in the t-t [lattice 1 S ( 3 9 S 1 ) channel for m =m :595. The inset 1S shows its enlargement. 8 3 The solid lines corresond to thesone-ion 1 exchange 7 otential (OPEP) given in Eq. (5). FIG. 4 (color online). t t deenden t!t channel for several different values of th = V (MeV) Lattce QCD simulation NN r (fm) V C (r) [MeV] r=.1

7 Exerimental Objectives at J-PARC S= s S= NN (T=1), n, nn S=-1 ΣN (T=3/2) ΣN-ΛN (T=1/2) S=-2 ΣΣ (T=2) ΞN-ΣΛ-ΣΣ (T=1) ΞN-ΣΛΛ (T=) Ξ S=-3 ΞΣ (T=3/2) ΞΣ-ΞΛ (T=1/2) S=-4 ΞΞ (T=1) S n 1a S= NN (T=) S=-1 ΣN-ΛN (T=1/2) S=-2 ΞN-ΣΛ (T=1) S=-3 ΞΣ (T=3/2) n Ξ Σ Σ + I 3-1 Λ +1 1s S=-1 ΣN (T=3/2) S=-2 ΞN-ΣΛ-ΣΣ (T=1) S=-3 ΞΣ-ΞΛ (T=1/2) S=-4 ΞΞ (T=) Ξ Ξ - -2 Ξ 8a S=-1 ΣN-ΛN (T=1/2) S=-2 ΞN-ΣΛ (T=1) ΞN-ΣΛΛ (T=) S=-3 ΞΣ-ΞΛ (T=1/2) Ξ 8s 1a S=-1 ΣN-ΛN (T=1/2) S=-2 ΞN-ΣΛ (T=1) ΞN (T=) S=-3 ΞΣ-ΞΛ (T=1/2) S=-2 ΞN-ΣΛΛ (T=) Ξ Ξ Anti-symmetric sin-orbit M = a + c (σ n 1+ σ n 2) + b (σ n 1- σ n 2) + mσ n 1σ 2 n + g(σ P 1σ 2 P + σ K 1σ K 2)+h(σ 1 P σ 2 P - σ 1 K σ K 2) I P y = 1/4 Tr(MM σ n 1) = 2 Re[(a+m)c* + (a -m)b*] ( I A y T= 1/4 Tr(Mσ n 2M ) = 2 Re[(a+m)c* - (a -m)b*] )

8 Calculation by Models S=-2 Ξ - ΛΛ, Ξ - Ξ - Polarization observables ( Anti-symmetric sin-orbit) P Σ (θ) Σ+ Σ+ Σ = 4 MeV/c QCM(RGM-H) QCM(FSS) OBE(NSC) OBE(Julich B) P Λ (θ) D Λ (θ) Λ Λ Λ = 6 MeV/c θ CM (deg) Λ Λ Λ = 6 MeV/c Δ(σ) 1% Δ(ol) a few - 1% θ CM (deg)

9 Method double scattering & decay (self-olarimeter) Production π Σ + (CH)n Scattering Σ + + Σ + + (CH)n Decay Σ + + π (51.57 %, α = -.98) Σ + n + π + (48.3 %, α =.68) Mean range of related charged articles... Σ + (incident) 8 mm Σ + (scattered) 5 mm (recoil) 18 mm (decay) 19 mm π + (decay) 44 mm

10 K+ double scattering & olarimeter π Σ- Σ π 2 4

11 K+ Σ- Exeriments at KEK-PS π- - - Σ π 2 4 Heart of exeriments (DUMAS & MUSASHI SciFi & IIT) E289 Sectrometer Magnet E452 K+ SciFi Liq. Scinti. Σ- π- - IITs - Σ- -4 Scintillating Fiber (or Liquid Scintillator) with IIT-CCD Camera triggered by Sectrometer system -2 π 2 4

12 Exeriments at KEK-PS IIT & Triggers Phoshor Decay Time a few µs Double trigger system for IIT 1st stage Phosher P-24 [! " 2.4 µs ] 2nd & 3rd stage Phosher P-2 [! " µs ] Decision Time several hundreds ns Fiber gated MCP gated MCP CCD 2nd Stage 3rd Stage CCD image handling Digitizer several tens ms VME Beam rate 1 5 Hz Image rate 1Hz 1st GATE by 1st level trigger dicision time " 3 ns width " 2.5 µs Fast detectors 2nd GATE by 2nd level trigger dicision time " 14 µs width " 1 m s Chamber hits Mass Trigger

13 Requests & Works at J-PARC for Ξ - (S=-2), Σ + and Λ(olarization obs.) reasonably doable at J-PARC Requests Searated beam line around GeV/c K - intensity 1 7 /sec with K/ > 1 Liquid hydrogen facility Work Realistic Otimization of Setu Background estimation (hysical & instrumental) Fast imaging device Trigger consideration Imrove rate limit 1 5 Hz 1 7(8) Hz

14 High-Seed Image Delay Tube - What is it? Prototyes ON THE OPTOELECTRONIC SCHEME OF A SCINTILLATING FIBRE TRACKING DETECTOR FOR FUTURE LARGE HADRON COLLIDER J.P.Fabre, T.Gys and M.Primout: CERN/EF/4147H/TG/mnb 8 November 1988 THE BASIC PRINCIPLE OF A VACUUM IMAGE PIPELINE T. Gys : CERN/EF/434H/TG/mnb 12 January 1989 Concetual design for an otelectric delay line J.P.Fabre, T.Gys, M.Primout and L.Van hamme: Revue Phys. Al. 24(1989)119 OPTOELECTRONIC DELAY FOR THE READ-OUT OF PARTICLE TRACKS FROM SCINTILLATING FIBRES T. Gys et al. : CERN/EF 89-25, DERN/LAA-SF91-3, CERN/DRDC OPTO-ELECTRIC DELAY TUBES T. Gys et al. : DERN/LAA/SF 9-2 A high-seed gateable image ieline Berkovski et. al. NIM A38(1996)537

15 High-Seed Image Delay Tube - What is it? Prototyes ON THE OPTOELECTRONIC SCHEME OF A SCINTILLATING FIBRE TRACKING DETECTOR FOR FUTURE LARGE HADRON COLLIDER J.P.Fabre, T.Gys and M.Primout: CERN/EF/4147H/TG/mnb 8 November 1988 THE BASIC PRINCIPLE OF A VACUUM IMAGE PIPELINE T. Gys : CERN/EF/434H/TG/mnb 12 January 1989 Electron drift velocity 1m/µs Concetual design for an otelectric delay line J.P.Fabre, T.Gys, M.Primout and L.Van hamme: Revue Phys. Al. 24(1989)119 OPTOELECTRONIC DELAY FOR THE READ-OUT OF PARTICLE TRACKS FROM SCINTILLATING FIBRES T. Gys et al. : CERN/EF 89-25, DERN/LAA-SF91-3, CERN/DRDC OPTO-ELECTRIC DELAY TUBES T. Gys et al. : DERN/LAA/SF 9-2 A high-seed gateable image ieline Berkovski et. al. NIM A38(1996)537

16 KEK - HSIDT (High-Seed Image Delay Tube) Visit Dr. T.Gys at CERN in June... learn things and hints examine the structure of a tube, and decide to assemble as a sectional detector... drawing & drawing &... Inut hotocathode and outut hoshor, grids, field-shaing electrodes, ceramic insulation, solenoid magnet, ulse generator, now assembling and test will be started soon...

17 KEK - HSIDT (High-Seed Image Delay Tube) Visit Dr. T.Gys at CERN in June... learn things and hints examine the structure of a tube, and decide to assemble as a sectional detector... drawing & drawing &... Inut hotocathode and outut hoshor, grids, field-shaing electrodes, ceramic insulation, solenoid magnet, ulse generator, now assembling and test will be started soon...

18 Y scattering ex. at J-PARC Channels T Observables,n 1 dσ/dω, Py, D,.. n n 1, dσ/dω, Py, D,.. Λ Λ Λ 1/2 dσ/dω, Py, AyT, D Σ + Σ + Σ + 3/2 dσ/dω, Py, AyT, D Σ Σ Σ 3/2, 1/2 dσ/dω, Ay Σ Λn 1/2 dσ/dω, Py Ξ Ξ Ξ 1, dσ/dω, Py, AyT (, D) Ξ Λ Λ dσ/dω, Py, AyT (, D)

19 Y scattering ex. at J-PARC with a CDC tracking detector SciFi & HSIDT K - Ξ - ΛΛ Ξ - Λ Λ [decay article detection] C B A 1 cm θ_sectrometer [ sectormeter] Target 5 cm wide 2 cm long A: roduction 1 cm Liq. Hydrogen B: degrader.5 cm Tungsten C: scattering 2 cm Liq. Hydrogen sectrometer θ_sectrometer ~ 25 at center K - beam LOI) Intensity 1 7 K - /sec Momentum 1.7 GeV/c Size σ_horizontal 15 mm σ_vertical 1 mm

20 a simulation K - intensity [s -1 ] 1 7 Number of Hydrogen [/cm2] Sectrometer [deg] 25 Sectrometer TOF [m] 5 Trigger rate ( ) [s -1 ] 11 Momentum of Ξ - [MeV/c] 3-1 cosθcm 1..5 Ξ - ΛΛ P Ξ [MeV/c] Ξ - Ξ - Ξ- ΛΛ reaction rate [s -1 ].9.43 days Detectable number 23 5

21 Summary Designing a Y exeriment Realistic Otimization of Setu for selected Y channel Background estimation (hysical & instrumental) Fast imaging device Trigger consideration High-Seed Image Delay Tube (made in Jaan) will soon be available Delay caability, Intrinsic time resolution of 1ns, Data reduction 1-3, Sace resolution of 3µm, Good efficiency... Next ste : Fast readout device keeing good sace resolution with large area

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