Testing the Standard Model with Parity-Violating Electron Scattering Where It s Been and Where It s Going

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Tsting th Standard Modl with Parity-Violating Elctron Scattring Whr It s Bn and Whr It s Going Mark Pitt * Virginia Tch Hadronic and Elctrowak Physics at MIT- Bats Rtrospctiv and Futur Prospcts

1 Tsting th Standard Modl with Parity-Violating Elctron Scattring Whr It s Bn and Whr It s Going Mark Pitt * Virginia Tch Hadronic and Elctrowak Physics at MIT- Bats Rtrospctiv and Futur Prospcts Follow historical path of PV - and -N parity-violating nutral wak currnt procsss trac both tchnological dvlopmnts and physics impact 1970 s : SLAC -d xprimnt 1980 s: MIT-Bats 1 C, Mainz MAMI 9 B 1990 s: SLAC E s: JLAB Q wak 010 s: JLAB PV and PV-DIS * Work partially supportd by th National Scinc Foundation

2 Elctromagntic and Wak Intractions : Historical Viw J EM, μ γ J EM, p μ p EM: + p + p lastic scattring M Q μ ( ψ γ ψ ) ( ψ γ ψ ) EM, p μ, EM, J μ J p μ p Q V x V - p Wak: n - + p + ν nutron bta dcay J wak, μ ν J wak, N μ n 50 th Annivrsary Yar Frmi (193) : contact intraction, form inspird by EM M J wak, N μ G F J μ, wak, μ ( ψ γ ψ ) G ( ψ γ ψ ) p μ n F V x V Parity Violation (1956, L, Yang; 1957, Wu): rquird modification to form of currnt - nd axial vctor as wll as vctor to gt a parity-violating intraction M J wak, N μ G F J μ, wak, 5 μ 5 ( ψ γ ( 1 γ ) ψ ) G ( ψ γ ( 1 γ ) ψ ) p μ n F (V - A) x (V - A) Not: wak intraction procss hr is chargd currnt (CC) ν ν

3 But l'dovich Suggsts - What About Nutral Wak Currnts? (1959) from Krishna Kumar

4 Th Nutral Currnt, l'dovich continud from Krishna Kumar

5 Standard Modl of Elctrowak Intractions (1967) Glashow-Winbrg-Salam Modl (1967): lctrowak - unifid EM and wak SU() L x U(1) gaug thory with spontanous symmtry braking frmions: υ R L, u R u, d', d' R L,...,... Intraction of frmions with gaug bosons: μ γ γ g μ 5 g ( γ μ f μ f μ 5 γ γ ) ( cv γ caγ γ ) cosθ W +,- W f f c t 0 V Standard modl tsts: Masur a varity of lctrowak procsss with couplings to all possibl frmions Extract valus of (sin θ W ) ff in a consistnt rnormalization schm from all procsss consistncy among ths succss of Standard Modl c f A 3 sin θw Q t f 3 f

6 N + γ N γ N N γ N N σ + h + (lastic scattring) + N + L R L R A σ σ σ σ γ Ζ γ p p 6 5 F ] [form factors,sin 4 G - πα W F Q θ Nutral Currnt Obsrvabl Parity-Violating Asymmtry

"Txtbook physics" - SLAC E1 Exprimnt, 1978-79 Charls Prscott and collaborators: - + d - + X, dp inlastic scattring at SLAC Q ~ 1.

7 "Txtbook physics" - SLAC E1 Exprimnt, Charls Prscott and collaborators: - + d - + X, dp inlastic scattring at SLAC Q ~ 1.6 GV first rsult in 1978: A - (15 ± 6) x 10-6 first masurmnt of parity-violation in th nutral wak currnt From D.H. Prkins, Intro. to High Enrgy Physics sin θ W 0.4 ± 0.00 Prscott t al., PLB 77, 347 (1978) Prscott t al., PLB 84, 54 (1978)

8 "Txtbook physics" - SLAC E1 Exprimnt, , continud "Finally, parity-violation in th nutral currnts was discovrd at th xpctd lvl in lctron-nuclon scattring at SLAC in 1978, and aftr that most physicists took it for grantd that th lctrowak thory is ssntially corrct." Stvn Winbrg "Th Making of th Standard Modl" on th occasion of th CERN 30th annivrsary clbration of discovry of nutral currnts AND 0th annivrsary clbration of discovry of W/ bosons hp-ph/

9 SLAC E1 Exprimntal Dtails E1 paramtrs E ~ 16.. GV, θ 4 o pulsd, 1.5 μsc at 10 Hz avrag currnts ~ 8 μa lctron polarization ~ 37% two indpndnt dtctors: N Crnkov and 9 X o Pb-glass showr countr E1 had ssntially all th faturs that continu to b usd in PV -, -N Polarizd sourc: photomission from GaAs polarizd sourc Rapid, psudo-random hlicity rvrsal Intgrat phototub outputs instad of puls counting (~700 MHz inst. rats) Slow hlicity rvrsal calcit prism g- prcssion chck Accurat masurmnt and control of bam proprtis (applid corrctions procdur for hlicity-corrlatd bam proprtis)

10 Parity-Violating Elctron Scattring Tsts of th Standard Modl ovr th Dcads Yar Exprimnt Asymmtry (ppm) sin θ W 1978 SLAC -d -15 ± 18 ± ± 0.00

MIT-Bats 1 C Exprimnt, 1979-89 Spoksprsons: Stanly Kowalski Paul Soudr - + 1 C - + 1 C

11 MIT-Bats 1 C Exprimnt, Spoksprsons: Stanly Kowalski Paul Soudr C C lastic Q ~ 0.0 GV T + 0 J 0 A + G F Q π πα sin θ W A 0.60 ± 0.14 ± 0.0 ppm sin θ W 0.04 ± ± Soudr t al., PRL 65, 694 (1990) smallst PV lctron scattring achivd to that point vry important xprimnt for idntifying and minimizing many critical systmatic ffcts

12 Bats 1 C Exprimntal Dtails Bats 1 C paramtrs E 50 MV, θ 35 o pulsd, 17 μsc at 60 Hz avrag currnts ~ μa lctron polarization ~ 37% quadrupol + lucit Crnkov Phototub signals wr intgratd by wid-gat intgrators and thn digitizd by 16 bit ADCs.

13 Bats 1 C Exprimntal Dtails polarizd sourc Cats t al., NIM A78, 93 (1989) Polarizd lctron sourcs: maintaining high quantum fficincy and liftim challnging rquirs propr prparation in UHV conditions On of ky tchnical improvmnts in PV xprimnts currntly achiving ~ 85% polarizations with suprlattic GaAs

14 Hlicity Corrlatd Bam Proprtis: Fals Asymmtry Corrctions A mas Exampl: A A phys + N 1 Y i 1 ( ) Y P i ΔP i ΔP P + P - Y Dtctor yild (P bam paramtr ~nrgy, position, angl, intnsity) 1 ( Y ) ~ 1.0 % / mm, Δ Y x x 100 nm A Y 6 ( ) Δx ~ 10 1 ppm 1 fals Y x Typical goals for run-avragd bam proprtis Intnsity: I I I + I + - I < ppm Position: Δx, Δy < - 0 nm ΔP P 1 ( Y ) Y P + P kp small with fdback and carful stup kp small with symmtrical dtctor stup

Bats 1 C Control of Hlicity-Corrlatd Bam Proprtis 1. Hlicity-corrlatd Intnsity PITA ffct - Polarization Inducd Transport Asymmtry causd by imprfct circular polarization - minimizd via activ fdback.

15 Bats 1 C Control of Hlicity-Corrlatd Bam Proprtis 1. Hlicity-corrlatd Intnsity PITA ffct - Polarization Inducd Transport Asymmtry causd by imprfct circular polarization - minimizd via activ fdback. Hlicity-Corrlatd Bam Position - Causd by th hlicity-dfining Pockls cll Lnsing : minimizd by adjusting transvrs position of cll Point-to-Point imaging from cll to photocathod with convrging lns A vn dpr undrstanding of Pockls cll systmatics cam in latr xprimnts (HAPPEX, E158 s Humnsky t al., NIMA 51, 61 (004).

16 Broadr Impacts of 1 C Prof. Gordon Cats U. Virginia Dr. Bob Michals Staff Mmbr, JLAB Prof. Krishna Kumar U. Mass. Amhrst

17 Mainz MAMI 9 B Exprimnt Hil t al., NPB 37, 1 (1989) B quasi-lastic Q ~ 0. GV A -9.4 ± 1.8 ± 0.5 ppm sin θ W 0.1 ± ± B xprimnt paramtrs E ~ 300 MV, θ o pulsd, 1.5 μsc at 10 Hz avrag currnts ~ 7 μa lctron polarization ~ 44% air Crnkov dtctor

C G L 5 5 1 PV -q γ γ γ γ γ γ μ μ μ μ W d A V d W u A V u W d V A d W u V A u

18 Modl Indpndnt Smi-Lptonic Analysis Particl Data Group way of analyzing low nrgy nutral currnt procsss uss ffctiv nutral currnt: [ ] + q q q F q q C q q C G L PV -q γ γ γ γ γ γ μ μ μ μ W d A V d W u A V u W d V A d W u V A u g g C g g C g g C g g C θ θ θ θ 1 1 sin 1 sin 1 sin 3 1 sin SM valus:

19 Parity-Violating Elctron Scattring Tsts of th Standard Modl ovr th Dcads Yar Exprimnt Asymmtry (ppm) sin θ W 1978 SLAC -d -15 ± 18 ± ± Mainz 9 B -9.4 ± 1.8 ± ±.014 ± Bats 1 C 0.60 ± 0.14 ± ±.048±.014

20 LEP/SLC Era Final rsults of LEP/SLC ra of masurmnts on th -pol hp-x/ Bst singl masurmnts (A LR (SLD) and A FB b ) hav ~ 0.1% prcision on sin θ W, but thy disagr by 3σ.

21 Running coupling constants in QED and QCD QED (running of α) QCD(running of α s ) 137 α s What about th running of sin θ W?

22 Running of sin θ W in th Elctrowak Standard Modl Elctrowak radiativ corrctions sin θ W varis with Q + + All xtractd valus of sin θ W must agr with th Standard Modl prdiction or nw physics is indicatd.

23 Why ar Prcision Masurmnts far Blow th -pol Snsitiv to Nw Physics? Prcision masurmnts wll blow th -pol hav mor snsitivity (for a givn xprimntal prcision) to nw typs of tr lvl physics, such as additional havir bosons. N N ' im M q g A Γ + + ' ' ' ' ' ' M q M g im M q g A Γ + + << 500 GV ~ 0.1% prcision, 1 1 ~, ~ pol, - At ' ' < + Γ M M M A M q.5 TV ~ 0.1% prcision, 1 1 ~, low nrgy, At ' ' < + << M M M A M q

24 Low Enrgy Wak Nutral Currnt Standard Modl Tsts Low nrgy wak charg triad (M. Ramsy-Musolf) probd in wak nutral currnt xprimnts SLAC E158: parity-violating Mollr scattring + + QW (1 4sin θ W ) N Csium Atomic Parity Violation: primarily snsitiv to nutron wak charg Q A W N + (1 4sin θ ) N W JLAB Q p wak: parity-violating -p lastic scattring + p + p Q p W 1 4sin θ W Ths thr typs of xprimnts ar a complmntary st for xploring nw physics possibilitis wll blow th pol.

25 Atomic Parity Violation in th Csium Atom (B x E) σ Bouldr 133 Cs xprimnt (Wood t al., Scinc 75, 1759 (1997)): Masurs modification of nutral wak currnt to th S-P Stark mixing in an applid lctric fild Isolat th parity non-consrving pic (PNC) with fiv diffrnt rvrsals PNC xpt. + atomic thory: Q W ( 133 Cs) ± (0.9) xpt ± (0.36) thor Standard Modl prdiction: Q W ( 133 Cs) ± (0.03) aftr a turbulnt -yar priod as th atomic thory was succssivly improvd. Futur dirction: try to masur APV in chain of isotops to liminat atomic structur uncrtaintis

26 Q wak : Elctron Wak Charg SLAC E158 Exprimnt + + Parity-violating Mollr scattring Q ~.06 GV θ ~ 4 7 mrad E ~ 48 GV at SLAC End Station A Final rsults: hp-x/ , PRL (005) A PV -131 ± 14 (stat) ± 10 (syst) ppb sin θ ff (Q 0.06 GV ) ± ± Running of sin θ ff stablishd at 6σ lvl in pur lptonic sctor

27 Running of sin θ W : Currnt Status and Futur Prospcts prsnt: d-quark dominatd : Csium APV (Q A W): SM running vrifid at ~ 4σ lvl pur lpton : SLAC E158 (Q W ): SM running vrifid at ~ 6σ lvl futur: u-quark dominatd : Q wak (Q p W): projctd to tst SM running at ~ 10σ lvl pur lpton :1 GV PV (Q W ): projctd to tst SM running at ~ 5 σ lvl

Ovrviw of th Q p Wak Exprimnt at Jffrson Lab -p lastic scattring Elastically Scattrd Elctron Elastically Scattrd Elctrons 5inchPMTinLowGain Intgrating Mod on Each End of Quartz Bar Rgion III Drift

28 Ovrviw of th Q p Wak Exprimnt at Jffrson Lab -p lastic scattring Elastically Scattrd Elctron Elastically Scattrd Elctrons 5inchPMTinLowGain Intgrating Mod on Each End of Quartz Bar Rgion III Drift Chambrs Rgion 3 Drift Chambrs 35 cm Luninosity Luminosity Monitors Exprimnt Paramtrs (intgration mod) Rgion II Drift Chambrs Toroidal Magnt Toroidal Magnt Rgion Rgion I Drift Chambrs GEM Dtctors Rgion 1 GEM Dtctors Collimator With Eight Opnings Collimator with θ 9± 8 opnings θ 8 ± 35 cm Liquid Hydrogn Targt Polarizd 35cm Elctron Liquid Bam Hydrogn Targt Polarizd Elctron Bam 580 cm Eight Eight Fusd Fusd Silica Silica (quartz) Crnkov Dtctors Črnkov Dtctors Incidnt bam nrgy: GV Bam Currnt: 180 μa Bam Polarization: 85% LH targt powr:.5 KW Cntral scattring angl: 8.4 ± 3 Phi Accptanc: 53% of π Avrag Q²: GV Accptanc avragd asymmtry: 0.9 ppm Intgratd Rat (all sctors): 6.4 GHz Intgratd Rat (pr dtctor): 800 MHz

29 Q p Wak Toroidal Magnt - QTOR 8 toroidal coils, 4.5m long along bam Rsistiv, similar to BLAST magnt Pb shilding btwn coils Coil holdrs & fram all Al B dl ~ 0.7 T-m bnds lastic lctrons ~ 10 o currnt ~ 9500 A Status: Bing assmbld at MIT-Bats magnt coils at MIT

30 Th Q p Wak Liquid Hydrogn Targt Targt Concpt: Similar in dsign to SAMPLE and G 0 targts longitudinal liquid flow high stram vlocity achivd with prforatd, taprd windsock Q p Wak Targt paramtrs/rquirmnts: Lngth 35 cm Bam currnt 180 μa Powr 00 W bam W hatr Rastr siz ~4 mm x ~4 mm squar Flow vlocity > 700 cm/s Dnsity fluctuations (at 15 Hz) < 5x10-5

31 Bam Polarimtry A Cautionary Tal from SLC SLC had Compton as primary polarimtr, but could cross compar with Mollr polarimtr. (1994) P 80.0 ± 0.9 ± 3.4% P 65.7 ± 0.9% P 69.0 ± 0.8 ±.9% Lvchuk ffct: importanc of targt lctron motion ffcts dpnds on accptanc (Lvchuk NIMA345, 496 (1994)) Upcoming xprimnts (Q wak, PV) nd ~1% prcision polarimtry: nw things bing studid atomic hydrogn targts, Mollr polarimtry at high currnts

32 Futur Prospcts at JLAB PV: Parity-Violating Mollr scattring at 1 GV JLAB (Mack, Rimr, t al.) Achiv Mollr focus with long, narrow rsistiv toroidal magnt, Radiation hard dtctor packag E 1 GV Q.008 GV, θ ~ o, A PV - 40 ppb 150 cm, 5 kw targt! In 4000 hours, could dtrmin Q W to.5% (compar to 1.4% for E158) δ(sin θ W ) ~ ; comparabl to bst singl masurmnts DIS-Parity at 6 GV (approvd), 1 GV (Paschk, Rimr, Soudr, hng) d, - p DIS at 6 GV and 1 GV Improv rrors on C u C d Masur nar NuTV Q Additionally, a broad program of hadronic issus will b studid - charg symmtry violation - d/u at high x - highr twist ffcts

33 Enrgy Scal of an Indirct Sarch for Nw Physics Paramtriz Nw Physics contributions in lctron-quark Lagrangian PV L -q PV L SM PV + L NEW G F γ μγ 5 C 1q q γ μ q q 4Λ γ μγ 5 q + g h q V q γ μ q A 4% Q p Wak masurmnt probs with 95% confidnc lvl for nw physics at nrgy scals to: Λ g 1 G F ΔQ W p.3 TV If LHC uncovrs nw physics, thn prcision low Q masurmnts will b ndd to dtrmin chargs, coupling constants, tc Q p Wak Q p Wak g: coupling constant, Λ: mass scal Mass Snsit ivit y vs ΔQ p Wak /Qp Wak 95% CL 68% CL projctd 4% (00 hours production) projctd 8% (14 days production) SLAC E158, Cs APV FrmiLab Run II projctd FrmiLab Run I ΔQ p Wak /Qp Wak (%)

34 Q p wak & Q wak Complmntary Diagnostics for Nw Physics JLab Qwak SLAC E158 u ~ LQ d u (proposd) - Run I + II + III (prliminary) ±0.006 u Erlr, Kurylov, Ramsy-Musolf, PRD 68, (003) Qwak masurmnt will provid a stringnt stand alon constraint on Lpto-quark basd xtnsions to th SM. Q p wak (smi-lptonic) and E158 (pur lptonic) togthr mak a powrful program to sarch for and idntify nw physics.

35 Rlativ Shifts in Proton and Elctron Wak Chargs du to SUSY Effcts R parity (B-L consrvation) RPC SUSY occurs only at loop lvl 0 χ + γ p χ p RPV SUSY occurs at tr lvl u ~ d u Erlr, Ramsy-Musolf, Su hp-ph/030306

36 W. Marciano (CIPNAP06): -pol: A LR vs. A FB b M H xp > GV (dirct limit) Implications of: 3 σ A LR (SLD) ± M H GV Standard Modl ruld out! A FBb 0.31 ± M H GV S +.55 ±.17 Room for 10 havy chiral doublts Favors tchnicolor! Ruls out SUSY! JLAB PV: δ(sin θ W ) ~ vry comptitiv could aid in rsolving discrpancy

37 Parity-Violating Elctron Scattring Tsts of th Standard Modl ovr th Dcads Yar Exprimnt Asymmtry (ppm) sin θ W 1978 SLAC -d -15 ± 18 ± ± Mainz 9 B -9.4 ± 1.8 ± ±.014 ± Bats 1 C 0.60 ± 0.14 ± ±.048± SLAC E ± ± ±.0010± ? JLAB Q wak ± ± ± ? JLAB ± ± ±.0003 Conclusions: Tchnical progrss in both statistics (bam currnts, polarizations, targt powr) and systmatics (bam polarimtry, hlicity-corrlatd bam paramtrs) has bn stady ovr th past thr dcads Th dram is that on of th futur xprimnts will turn out to b as important and influntial as th first on!

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