Effects of e ± Polarization on the Final States at HERA

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Effcts of ± Polarization on th Final Stats at HERA Ringbrg Workshop Nw Trnds in HERA Physics 003 8 Sptmbr - 3 Octobr

1 Effcts of ± Polarization on th Final Stats at HERA Ringbrg Workshop Nw Trnds in HERA Physics Sptmbr - 3 Octobr 003 Uta Stösslin (DESY Hamburg) Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 1

2 Outlin HERA II Polarization Dpndnt Inclusiv Cross Sction CC, NC Dply Virtual Compton Scattring cross sction, asymmtris Asymmtris in Particl Production Bam Spin Transfr to Λ-Baryons ZEUS Conclusion Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA

First Polarizd @H1+ZEUS in 003 p 319 GV LPOL 5 min. Avrag Mar003 TPOL 5 min.

3 First in 003 p 319 GV LPOL 5 min. Avrag Mar003 TPOL 5 min. Avrag Polarization % Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 3 Day

4 Th HERA II Bam Options -bam + and - bam charg dpndncis longitudinally paralll/anti-paralll polarizations with xpctd valus up to 50-60% with a prcision of δp/p~1% bam spin dpndncis nhancd physics potntial! high luminosity up to 1fb -1 until 006, i.. about 00pb -1 pr sampl + (λ=±1), - (λ=±1) xpctd and wantd but p-bam unpolarizd still! no accss to polarizd proton and photon PDFs (rquirs doubl spin asymmtris) Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 4

5 Th Classic s Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 5

6 Classic Goal (I): Sarch for Right-Handd Currnts in CC DIS - L W L ν L? - R W R? ν R? tim u L λ=-1 d L u R λ=+1 d R forbiddn in Standard Modl: σ CC 0 for ± R txtbook masurmnt! Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 6

7 Simulation of σ ± CC (λ) λ ( ) ( ) ± ± Q Y W Y xw ± πα 1± CC 4 W 3 σ = κ xq with Y = - y + y /(1 + R) + Y = 1 -(1 - y) σ CC TOT (Q > 00 GV ) (pb) A.Mhta DIS0 - p Data (Prlim. 16 pb -1 ) - p SM s=30 GV - p SM (MC) s=30 GV (50 pb -1 ) κ = W Q 1 Q + M 4sin θ W W 1 for Q M W 60 + p Data (48 pb -1 ) + p SM s=300 GV 50pb -1 pr λ=±0.6 modst luminosity but high polarization ndd p SM (MC) s=300 GV (50 pb -1 ) nw physics byond SM if any dviation from straight lin Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA HERA I data P

8 Classic Goal (II): Parity Violation in NC γ + Z p X p X intrfrnc of lctromagntic and wak nutral currnts vctor (v) and axial-vctor (a) contributions d σ ( λ) πα dq dν xq { } int = 4 κ Z = ( Q ) Y ( R 0) G (-v ± λa ) Y xg ( a λv ) + - dpnding both on bam polarization λ and bam charg (±) nw structur functions G and xg 3 containing quark couplings to th Z boson q q q ( ( ) ( )) ( ) ( ) G(x) = xσ v q x+q x 3 q q q ( ) xg (x) = -xσ a q x -q x v = T - a = T f 3f f Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 8 f 3f si n θw

9 Asymmtris in NC DIS varying bam polarization [d: SLAC 1978] on parity-violation asymmtry pr bam charg ( ) A λ, λ = 1 ( ) ( ) d 1 ( ) ( ) d dσ λ - σ λ dσ λ + σ λ 1 varying of both λ and bam charg [µc: BCDMS 1981] bam conjugation asymmtry ( ) B λ, λ = 1 ( ) ( ) d 1 ( ) ( ) d - dσ + λ - σ - λ dσ + λ + σ λ 1 = -κ Z λ -λ 1 ( ) 1 1 y a G v xg F F 1+ 1-y ( ) ( ) { ~0 for y 1 ~1 for y 0 ( λ - λ ) xg ( 1-y) F -κ Z a + v 1 ( 1 ) + -y { unpol. γz -intrfrnc contribution masurmnts rquir high polarization valus and high Q valus 1 Q -4 κ Z = 1.7i10 Q /GV 4cos θwsin θ W MZ + Q Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 9 { ~0

10 Simulation of G (x,q ) at high Q for λ =-λ 1 and v =0: using approximation: x 1 G A ( λ ) = κλa ~ ± κλ F Z Z ( ( + ) + ( + )) 1 F x 4 u u d d 9 G (( ) x u+ u + ( d+ d) ) 9 1+ d v/u 4+ d /u xtraction of G (x,q ) using knowldg of F (x,q ) v v v Singltt+ Non-Singltt Singltt 00pb -1 pr λ =± 0.5 M.Klin DIS01 Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 10

11 Tst of Elctrowak Paramtr J.Blümlin t al. HERA WS87 mploy bam polarization and charg to tst M W or sin θ W via parity-violation asymmtry A ± (λ) cross sction ratio R ± (λ) R ± σ λ = σ ( ) ( λ) ( λ ) stat. rror of M W from R - bst and only 5% wors if λ=0 instad of -1 (δλ=1%) although σ CC (λ=-1)/ σ CC (λ=0)~ ± NC ± CC [%] A - R - 00pb -1 Λ=0.8 Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 11

12 Th Nw Classic s Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 1

13 Dply Virtual Compton Scattring DVCS Bth-Hitlr factorization γ * γ γ * γ γ * γ p p p p p t=- nw info on structur a) of nuclon! b) c) p diffractiv production of a ral photon d 4 σ/dxdq d t dф τ DVCS + τ BH + τ* DVCS τ BH + τ DVCS τ BH * DVCS : QCD procss snsitiv to undrlying dynamics Bth-Hitlr : QED procss background and intrfrnc Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 13

14 DVCS : Modls GPD basd modls Color Dipol basd modls dipol siz R x 1 P x P handbag b impact paramtr dominant at low x GPD incorporat both a partonic and distributional amplitud bhavior accss to dynamical rlation btwn diffrnt partons (particl corrlations, orbital angular momntum) thr-dimnsional distribution of nuclon substructur QCD pictur (hard scattring factorization: LO, byond LO, byond twist-) simpl unifid pictur of diffractiv procsss match soft and hard rgims implmntation of.g. saturation ffcts broad phnomnology Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 14

dnsity GPD at η=0 s also talks by A.Frund and C.

15 Nuclon Holography [V.Blitsky, D.Müllr,hp-ph/006306] [M.Burkhardt,PRD6(000)071503] GPD provid transvrs location of partons in th nuclon form factor parton dnsity GPD at η=0 s also talks by A.Frund and C.Wiss at HERA 3 WS0 1/ b~1/(t) - Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 15

16 DVCS : Exprimntal Signaturs BH γ DVCS intrfrnc rgion γ [hp-x/030508] Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 16

17 DVCS : Cross Sction vs W H1 [EPS03] δ 6pb -1 W dpndnc matchs W 0.7 bhavior of hard VM production Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 17

18 DVCS : Cross Sction vs Q H1 6pb -1 95pb -1 fit Q -n Q dpndnc wll dscribd by GPD or color dipol basd modls (intgratd ovr xp. t rang) HERAII : factor 10 mor statistics xpctd Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 18

19 [V.Blitsky t al.,hp-ph/011108] Angular Dpndncis of p pγ Cross Sction angl btwn th lpton and hadron scattring plans ф = ф N - ф l γ* ф γ rcoild p BH DVCS Intrfrnc Complx and rich angular structur of th cross sction! But, which angular dpndncis ar th rlvant ons? Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 19

20 Contributions for an Unpolarizd p mploy angular structur to accss mor obsrvabls, in particular in dpndnc on bam spin (λ) and charg (±) cosф, cosф cosф, λsinф twist-3! T pol. p only charg dp cosф, λsinф sinф L,T pol. p only known cosф-dpndnc du to lpton BH propagators cosф, λsinф twist-3! DVCS amplitud with gluon transvrsity (twist-, but α S powr supp.) : - squard DVCS trm : cosф and sinф dpndncis - intrfrnc trm : cos3ф and sin3ф dpndncis BH trm: bam polarization dpndnc only in cas of longitudinally or transvrsly (L,T) polarizd targt! Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 0

21 Bam Charg and Azimuthal Asymmtry varying bam charg [HERMES 00] bam charg asymmtry (CA) or counting vnts scattrd up and blow lpton scattring plan to gt cosф wight bins in ф CA ~ R (τ BH τ DVCS ) varying azimuthal angl (bam spin and charg fixd) azimuthal angl asymmtry (AAA) rquirs vry good ф rsolution and control of twist-3 contamination AAA ~ R (τ BH τ DVCS ) Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 1

22 Bam Spin Asymmtry varying bam polarization [HERMES, CLAS 001] on bam spin asymmtry (SSA) pr bam charg or counting vnts scattrd up and blow rotatd-by-90 o lpton scattring plan (lft and right) to gt sinф wight bins in ф SSA ~ Im (τ BH τ DVCS ) combination of SSA and CA or AAA givs accss to full twist- τ BH τ DVCS amplitud BH contributions absnt in CA and SSA masurmnts Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA

23 Unviling GPD H unviling GPDs from dtrmination of Fourir cofficints obtaind from asymmtry masurmnts CA AAA SSA K ~- /Q ~1/10 λ } high y ndd high γ* pol. H (unpol. non-spin-flip) lik q, q, g H (pol. non-spin-flip) lik q, q, g E (unpol. spin-flip) no inlcusiv quivalnt! E (pol. spin-flip) no inlcusiv quivalnt! H Compton Form Factors ar convolutions of cofficint functions and GPDs : H,H,E,E appar in linar combinations in intrfrnc trm but in quadratic combinations in unpol. cross sction accss both parts of CFF H complt spration of GPD would rquir in addition data takn with polarizd (T,L) targt Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 3

24 CA Simulation for HERA intgratd ovr t, -t<0.5gv, and ovr ф [A.Frund, hp-ph/030601] x x Q [GV ] Q [GV ] Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 4

25 SSA Simulation for HERA (( + p) intgratd ovr t, -t<0.5gv, and ovr ф [A.Frund, hp-ph/030601] x x Q [GV ] Q [GV ] Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 5

26 Som Masurmnt Rmarks ф and t ar difficult to masur sinc scattrd proton is not obsrvd [R.Stamn, HERA3 WS0] ф = ф - ф p ф - ф γ t = (p - p ) - p + p T T γ dtrmination of ф and t via scattrd and γ : DVCS : backward and cntral γ and vto on p-diss background ( forward instrumntation) t dominatd by E and θ rsolution of γ ф dominatd by E rsolution of H1 prlim [EPS03] Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 6

27 H1 VFPS and DVCS [L.Favart, Trnto03] bttr supprssion of p-diss background som bins in t sys (b-slop) ±GV - [H1-PRC01/00] mor bins in ф? DVCS vnts for 1fb -1 Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 7

28 Simulations for HERA : Som Rmarks CA and SSA asymmtris prdictd to b sizabl, calculations in LO, NLO, and twist-3 availabl, s also [V.Blitsky t al.,hp-ph/011108] changing of t cut-off to 1GV altrs rsults on 10% lvl AAA prdictd to hav similar siz as CA twist-3 ffcts stimatd to b ngligibl for CA and for SSA NLO corrctions ar larg, up to 100% for CA and up to 50% for SSA (larg NLO gluon contribution in ral part of DVCS amplitud) NLO corrctions important for prcision xtraction of GPDs in gnral: cross sction and asymmtry data can b wll modld, but too many paramtrs not constraind yt! asymmtry masurmnts fasibl! Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 8

29 [V.Blitsky, D.Müllr,hp-ph/ ] Tim-lik Virtual Compton Scattring lctroproduction of muon pairs allows clar study of GPDs via singl bam spin, singl hadron spin, bam charg, azimuthal and doubl spin asymmtris mploying angular dpndncis of rcoild p and of lpton pair mapping in both scaling variabls η and ξ constrain angular momntum sum rul: Ebam E = 11GV = 5GV E = 40GV bam bam q η = p q but cross sction vry small high luminosity! Q ξ ;xb p q 1+ ξ = = ξ Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 9

30 Anothr viw on th angular momntum sum rul [V.Blitsky t al.,hp-ph/011108] with proton and nutron magntic momnts and κ sa is th orbital angular momntum carrid by th quarks momntum fraction P i carrid by th quarks can b dducd from DIS data alon Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 30

31 Elastic Particl Production slct diffrnt GPDs (and quark flavors) via dtction of diffrnt final stats vctor msons :,.g. ρ 0 J u +J d [X.Ji,hp-lat/011016] H,E H,E psudoscalar msons : su transitions within th baryon octt : transition GPDs,.g. Hp-> Λ but additional complication du to prsnc of distribution amplitud of th particl,.g. th pion wav function for unpol. bam and transv. pol.. targt larg asymmtris hav bn prdictd, s.g. [K.Gok t al, hp-ph/010601] HERMES, CLAS, COMPASS γ p -> K L * + spcial : xclusiv strangnss production whr an azimuthal spin asymmtry can b masurd on an unpolarizd targt by masuring th polarization of th rcoiling hypron through its angular distribution not studid yt for HERA Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 31 Λ

32 Singl Spin Asymmtry in π lctroproduction CLAS: first obsrvation of a positiv SSA in SiDIS π + production [CLAS,hp-x/ ] but xpctd to b zro in LO rlatd to ithr NLO or highr twist ffct NLO : [A.Afanasv,C.E.Carlson,hp-ph/ ] final stat gluon xchang dlivr contribution to + anti-symmtric part of hadronic tnsor lpton bam spin asymmtry is gnratd du to intrfrnc btwn absorption of longitudinal and transvrs virtual photons A LU ~r / Q T with transvrs componnt of th final quark momntum r T twist-3 3 : [A.V.Efrmov t al.,hp-ph/00814] SSA ariss from chirally odd twist-3 proton distribution function a (x) in combination with chirally-odd and T-odd twist- Collins FF vry intrsting to tst it also at HERA Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 3

33 Bam Spin Transfr to Λ-Baryon [M.Anslmino,hp-ph/030008] four indpndnt obsrvabls: in currnt fragmntation rgion pol. FF D ( ) Λ /q z snsitiv to distribution of polarizd quarks in unpolarizd nuclon Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 33

Longitudinal Λ Polarization parity violating wak dacy of Λ pπ distribution of dcay angl θ* dpnds on Λ pol. P : I(θ*) ~ 1 - α P cos θ* (α=0.64) xp.: P Λ = P bam D(y) S Λ rquirs high bam pol.

34 Longitudinal Λ Polarization parity violating wak dacy of Λ pπ distribution of dcay angl θ* dpnds on Λ pol. P : I(θ*) ~ 1 - α P cos θ* (α=0.64) xp.: P Λ = P bam D(y) S Λ rquirs high bam pol. and high y Λ could contain polarizd quark! using rlation pol FF pol PDF Gribov-Lipatov rciprocity rlation [1971] [C.Rislr,H1,PhDthsis] K S study Λ spin structur and tst SU(3) f : [.g. B.Ma t al., hp-ph/0081] Λ 0 Λ spin proton spin mor data ndd! masurmnts sms to b fasibl π momntum paralll antiparalll to Λ flight dirction Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 34

35 Conclusion HERA II with high luminosity and with longitudinally polarizd lctrons and positrons opns nw horizons to study lctrowak thory and parton dynamics and may dlivr vn surpriss w could not imagin today For fruitful discussions I lik to thank Markus Dihl, Andras Frund, Marco Stratmann, Christian Rislr. Ringbrg Workshop 003 Uta Stösslin Effcts of ± Polarization on th Final Stats at HERA 35

Electroweak studies and search for new phenomena at HERA

Electroweak studies and search for new phenomena at HERA Elctrowak studis and sarch for nw phnomna at HERA A.F.Żarncki Warsaw Univrsity for ZEUS A.F.Żarncki Elctrowak studis and sarch for nw phnomna at HERA p./25 Outlin Introduction HERA and xprimnts A.F.Żarncki