Spin Physics (Experimental)

Transcription

1 SPIN, Stangeness and QGP. Raimondo Betini *. *Univesita and INFN-Toino Spin Physics (Expeimental)

2 OUTLOOK What is SPIN Polaised souces Polaised beams Polaised tagets Polaimetes Measuement of spin obsevables Futue pojects 9-15/10/005 Raimondo Betini

3 Why Spin? Sten- Gelach expeiment (191) G.E. Uhlenbeck and S.A.Goudsmith (195) 9-15/10/005 Raimondo Betini

4 Electon Spin The electon is not point like. In addition to its obital angula momentum about the nucleus, an electon otates like a top. This new intinsic electon motion was called SPIN. Magnetic moment poblems Ex: Yang-Hamilton Moden Atomic and Nuclea Physics McGaw-Hill 9-15/10/005 Raimondo Betini

5 Magnetic Moment 9-15/10/005 Raimondo Betini

6 9-15/10/005 Raimondo Betini

7 Magnetic moment of the electon 9-15/10/005 Raimondo Betini

8 Sten-. Gelach Expeiment Z Physik 9 (19) /10/005 Raimondo Betini

9 9-15/10/005 Raimondo Betini kt z d D B kt z d D B g m kt z d D B z dzmv d B mv F t dx dz k T mv z B z B j j z z z z z tan tan tan ± μ μ μ μ θ

10 Sten-Gelach Expeiment Z. Physik 9 (19) 49 Deflection z μ B Bz z z 10 T m ; d 1 m ; D m ; T 400 K k z B ± 1.1 cm z 5 dd 3kT ev K ; μ B ev T 9-15/10/005 Raimondo Betini

11 Results 9-15/10/005 Raimondo Betini

12 9-15/10/005 Raimondo Betini Tansitions ( ) 1 0, ± Δ > m and g g as B B B m g g m h h B m g E E B g m E E E E E E h B mg B B U B B B B B B z μ μ μ ν ν μ μ ν μ μ μ

13 9-15/10/005 Raimondo Betini Nucleon Spin ( ) ( ) ( ) T ev c m e S L c m e T ev m c e S L S L m c e p N s p s p p p e B B s e l e e e g g g g 8,, 4,, ; h h h h μ μ μ μ μ

14 Spin Rotation ds dt s Ω e m γ s [ ] ( 1+ γg) + ( 1+ G) Bt Blong ν γ γ sp G G 1+ γ k k P G + ( impefection esonances) ν z ( int insic esonances) 9-15/10/005 Raimondo Betini

15 Tools to peseve spin duing the acceleation Sibeian snakes RFQ See RHIC 9-15/10/005 Raimondo Betini

16 Installed and commissioned duing un 4 To be commissioned Installed/commissioned in un /10/005 Raimondo Betini

17 Othe Polaised beams π ± μ ± + ν μ J Λ p + π /10/005 Raimondo Betini

18 Polaimetes Measue polaisation via an inteaction spin dependent Ex. Pp elastic scatteing Measue angula distibutions of weak decays Ex. Λ p + π- B.R α /10/005 Raimondo Betini

19 Λ Polaisation 9-15/10/005 Raimondo Betini

20 9-15/10/005 Raimondo Betini

21 Coss-section depends on spin Scatteing of neutons by otho and paahydogen Schwinge and Telle Phys. Rev. 5 (1937) 86 Paa-H² (J0 S0) Otho-H² (J1 S1) Tansition paa otho ΔE 0.03 ev 9-15/10/005 Raimondo Betini

22 Poton-Poton elastic scatteing 1 P.R.L. 85 (000) /10/005 Raimondo Betini

23 9-15/10/005 Raimondo Betini Analyzing powe Ex. Poton-poton elastic scatteing ( ) ( ) ( ) ( ) ω ϕ θ σ ω ϕ θ σ ω ϕ θ σ ω ϕ θ σ d d d d d d d d P A b N +,,,, 1

24 Poton-Poton elastic scatteing 9-15/10/005 Raimondo Betini

25 9-15/10/005 Raimondo Betini

26 Antipoton-poton total coss-sections p p 9-15/10/005 Raimondo Betini

27 Antipoton-poton diffeential coss-sections /10/005 Raimondo Betini

28 Antipoton-poton diffeential coss-sections 9-15/10/005 Raimondo Betini

29 Antipoton-poton analyzing powes 9-15/10/005 Raimondo Betini

30 Polaised tagets spin 1/ Gaseous polaised tagets Fozen spin polaised tagets T0.5 K; B.5 T P(el) ; P(nucl) P n n n± + faction of spins m ± 1 n n + exp E m kt s exp mgμb B kt s 9-15/10/005 Raimondo Betini

31 9-15/10/005 Raimondo Betini Dynamic Polaisation ( )( ) spins nucl el dip I S I S g g H enegies Zeeman nuclea and electon IZ and SZ simplified H H H H H n e SI RF SI IZ SZ.. int h

32 κ T -dependent Paton Distibutions Twist- PDFs f 1 g 1L g 1T h 1T Distibution functions Chiality even odd f 1, g 1 studied fo decades: h 1 essentially unknown f 1T h 1 Twist- U L T f 1 h1 g 1 h1l, h 1, f 1T g 1T h1t P S k p x P+ k quak p f1(x) d k T f T 1 (x,k T ) T h 1L h 1T 9-15/10/005 Raimondo Betini

33 Tansvesity and Λ Polaisation 9-15/10/005 Raimondo Betini

34 Semi-inclusive deep inelastic scatteing 9-15/10/005 Raimondo Betini

35 9-15/10/005 Raimondo Betini Kinematics of Λ poduction ( ) ( ) E P k P q y EE m m k k E E q Q M Q x E E M P q l l ν ϑ ν ν sin 4 ;

36 Definition of Λ polaisation axis 9-15/10/005 Raimondo Betini

37 The COMPASS setup μω SDC SciFi Taget Rich1 ECal1 HCal1 μwall1 Fist Spectomete: LAS Geometical Acceptance: θ>30 mad Gap: 17 9 cm Integal field: 1 Tm Analyzed momentum: p<60 GeV/c SDC GEM Staw SM1 SciFi GEM MWPC SM Second Spectomete: SAS Geometical Acceptance: θ<30 mad Gap: cm Integal field: 4.4 Tm Analyzed momentum: p>10 GeV/c 50 m ECal HCal MWPC μwall 9-15/10/005 Raimondo Betini

38 9-15/10/005 Raimondo Betini

39 Selection of Λ events 9-15/10/005 Raimondo Betini

40 Data Analysis /10/005 Raimondo Betini

41 Data Analysis 9-15/10/005 Raimondo Betini

42 Available statistics 9-15/10/005 Raimondo Betini

43 COMPASS Tigge 9-15/10/005 Raimondo Betini

44 Study of systematic effects 9-15/10/005 Raimondo Betini

45 Tansvese Stuctue Functions Fo q non collinea with hadon ( k xp+ k ) f 1 (x,k ) g 1 (x,k ) h 1 (x,k ) f(x) f(x,k ) integating on k f(x), Δf(x), Δ T f(x) g 1T (x,k ) h 1L (x,k ) h 1T (x,k ) integating on k 0 elaxing time evesal invaiance f 1T (x,k ) fo unpolaized quak in tansvesally polaized hadon (Sives function) h 1 (x,k ) fo tansvesally polaized quak in unpolaized hadon 9-15/10/005 Raimondo Betini

46 9-15/10/005 Raimondo Betini Tansvese Stuctue Functions (Dell-Yan) X μ μ p) pp( + π Kinematics q P M x 1 1 x x x 1 F q P M x s M x x τ 1

47 Dell-Yan Asymmeties Polaised beam and taget Uncoelated quak helicities access chially-odd functions TRANSVERSITY Ideal because: h 1 not to be unfolded with fagmentation functions chially odd functions not suppessed (like in DIS) 9-15/10/005 Raimondo Betini

48 Tansvese Stuctue Functions (Dell-Yan) 1 σ dσ dω Di-Lepton Rest Fame 3 1 ν 1+ λcos θ + μsin θcosφ + sin 4π λ + 3 θcosφ Femilab π-n 5 GeV/c -0.6 < cosϑ < < M < 8.5 GeV/c 9-15/10/005 Raimondo Betini

49 Tansvese Stuctue Functions (Dell-Yan) Initial state inteactions non zeo σ dσ dω h (x κ 1, 3 1 ν 1+ λcos θ + μsin θcosφ + sin 4π λ + 3 θcosφ 1 NLO pqcd: λ 1, μ 0, υ 0 Expeimental data [1] : υ 30 % ) [1] J.S.Conway et al., Phys. Rev. D39(1989)9. υ involves tansvese spin effects at leading twist [] : cosφ contibution to angula distibution povide: h 1 (x, κ ) h1 (x1, κ ) [] D. Boe et al., Phys. Rev. D60(1999)01401, D.Boe, S.Bodsky and D.S.Hwang 9-15/10/005 Phys.Rev.D67(003) Raimondo Betini

50 Tansvese Stuctue Functions (Dell-Yan) Dell-Yan asymmeties - Polaized taget, Unpolaized beam 1 σ dσ dω 1+ cos 9-15/10/005 Raimondo Betini θ + ν sin sin θsin(φ φ S ) 1 A T S1T 1+ cos θ θcosφ + ρs λ 1, μ 0 M Q e 1T sin θsin(φ φ S 1 ) + L [ ] a a a a x f (x )f (x ) + x h (x )h (x ) a a a a e a af1 (x 1)f1 (x ) Unpolaised beam and poliized taget is a poweful tool to investigate к T dependence of QDF D. Boe et al., Phys. Rev. D60(1999)01401, D. Boe et al Phys.Rev.D67,054003,003

51 Tansvese Stuctue Functions (Dell-Yan) Phase space τ const: hypebolae x F const: diagonal 15 GeV/c 30 GeV/c PANDA (GSI) 40 GeV/c ASSIA (GSI) COMPASS (CERN) 9-15/10/005 Raimondo Betini

52 Tansvese Stuctue Functions (Dell-Yan) Upgaded COMPASS spectomete New poliazed taget (wide acceptance) GEM, MICROMEGA detetos σ 70 μmsmall angle MWPC, STRAW detectos vetex esolution σ mm LARGE AREA HODOSCOPEs Tigge mmlage angle Iaocci like tubes o lage aea dift chambes μid New Poweful E-caloimey σ cm 9-15/10/005 Raimondo Betini

53 Tansvese Stuctue Functions (Dell-Yan) Dell-Yan Counting ate: Realistic appoach, the intensity of the beam 10 8 π s 1 Taget: 15 g/cm Luminosity: L NH cm s 17 (4GeV M 9GeV ) μ + μ Coss section value A nb/nucl Acceptance A 0.5 Expected ate: R 9-15/10/005 Raimondo Betini events/s

54 Dell-Yan Di-Lepton Poduction pp μ + μ X d σ dm dx F 4α π 9M s x x [ ] a a a a f (x )f (x ) f (x1)f (x ) ea 1 + a Scaling: d d σ τdx F 1 s Full x 1,x ange τ 0,1. p BEAM 40 Gev/c needed [ ] σ pp μ + μ X 0.3 nb [ 1] [1] Anassontzis et al., Phys. Rew. D38 (1988) /10/005 Raimondo Betini

55 9-15/10/005 Raimondo Betini

56 Open Cham ΔG Open cham fom Λ + c X poduction and subsequent + Λ π + weak decay Λ c low banching atio: B.R. 0.9% huge self-analysing asymmety: α 0.98 σ pp 40 c [1] Assume GeV? 1 μb p, Λ longitudinally polaised 9-15/10/005 c c Raimondo Betini -3 # ev /s ev/100 days [1] Smith Vogt Z. Phys. C75 (1997)71

57 9-15/10/005 Raimondo Betini

58 Stong Spin Flip Inteaction 9-15/10/005 Raimondo Betini