Precision Standard Model Tests (at JLab)

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Winfred Ramsey
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1 Prcision Standard Modl Tsts (at JLab) Xiaochao Zhng Jun 21st, 2018 Th Standard Modl of Particl Physics How should w sarch for nw physics? Prcision SM tsts at Jffrson Lab Qwak, PVDIS Mollr, 12 GV PVDIS

2 From Lptons and Quarks to th Cosmos human: atoms: proton: 10-15m uark: 100m 10-10m Solar systm: 108m Milky Way: lctron: 1021m <10-19m <10-18m? Planck th ntir lngth: univrs: 10-35m 1029m? obsrvabl univrs: 1027m

3 Th Standard Modl SIZE IN ATOMS SIZE IN METERS ,000 (1) th lmntary frmions uarks and lptons (2) th symmtris (of chargs intractions) (3) th origin of masss n 1 100,000 p 1 100,000,000 uarks at most τi μ Y μ λα μ D = i g1 B i g 2 W i ig 3 G α μ μ

4 Limits of th Standard Modl Th Standard Modl is an ffctiv thory at th lctrowak scal (choos your favorit:) Why ar thr thr gnrations of uarks and lptons? Why do uarks hav chargs +2/3 or -1/3? Why do protons and lctrons hav opposit chargs? How do w includ gravity in uantum fild thory? How do w xplain dark mattr? Why ar nutrinos so light in mass? And many mor!

5 Caught in th Act! Could this b an indication that uarks and lptons ar composit particls? And what if thy ar??

6 How should w procd? Look mor into math Can th symmtris b unifid? (Grand unification thory); Can thr b highr lvls of symmtris (suprsymmtry)? look for nw phnomna prdictd by GUT. Look mor into mattr, ar thr mor layrs byond uarks and lptons? lpton and uark compositnss Look mor into xisting discrpancis muon g-2, proton radius, dark mattr (sarchs) masur thm to highr prcision! but can b cloudd by xprimntal systmatics, or th ability to xprimnt! Try to find nw discrpancis by masuring physical uantitis to high prcision rar dcays, univrsality, EDM, prcision PVES Look for nw particls, nw phnomnon, forbiddn procsss tc a littl hardr, sinc it may not b clar whr to look (th simplst xtnsion to SM would b anothr U(1) group/symmtry, a lptophobic Z... )

7 τi μ Y μ λα μ D = i g1 B i g 2 W i ig 3 G α μ μ SU(5) multiplt: ν W s d r d g d b gluons ( ) (( )) U(1)xSU(2)xSU(3)? That s too many groups! Lt s mak it on! nw gaug bosons X and Y... L It is crtainly vry attractiv. It xplains why uarks hav chargs +2/3 and -1/3 (of ). It unifis all thr forcs ( 1,2,3) to on ( 5)! On way to look for GUT is to masur proton dcay p + pi0, prdictd liftim 1031 yars (or longr).

8 How should w procd? Look mor into math Can th symmtris b unifid? (Grand unification thory); Can thr b highr lvls of symmtris (suprsymmtry)? look for nw phnomna prdictd by GUT. Look mor into mattr, ar thr mor layrs byond uarks and lptons? lpton and uark compositnss Look mor into xisting discrpancis muon g-2, proton radius, dark mattr (sarchs) masur thm to highr prcision! but can b cloudd by xprimntal systmatics, or th ability to xprimnt! Try to find nw discrpancis by masuring physical uantitis to high prcision rar dcays, univrsality, EDM, prcision PVES Look for nw particls, nw phnomnon, forbiddn procsss tc a littl hardr, sinc it may not b clar whr to look (th simplst xtnsion to SM would b anothr U(1) group/symmtry, a lptophobic Z... )

9 Rcall your Modrn Physics Homwork? SIZE IN ATOMS E (binding nrgy) SIZE IN METERS lctrons in an atom 1 10,000 n 1 100, ,000, p uarks at most m V nuclons in th nuclus 10(-14~-15)m 102MV 101MV uarks in nuclons 10-15m prons in uarks and lptons: 10-19~-18 prons? kv 102MV ( 102MV) 2 10 GV m?-tv TV?

10 Rcall your Modrn Physics Homwork? SIZE IN ATOMS E (binding nrgy) SIZE IN METERS lctrons in an atom 1 10, , ,000,000 p uarks at most uarks in nuclons 10-15m prons in uarks and lptons: 10-19~-18 m V 102MV ( 102MV) ~1TV ~1TV If prons xist, thy must intract through a nw intraction, with an nrgy scal at th TV lvl; Th ffct would b xtrmly small at low nrgis. Howvr, this sms impossibl, as thn uarks and lptons must hav rst mass (nrgy) at TV lvl. prons? kv nuclons in th nuclus 10(-14~-15)m 102MV 101MV n m

11 Look mor into mattr, ar thr mor layrs byond uarks and lptons? Ys, Th word "atom" (a-tomos) originats from ancint Grk philosophrs, who argud that objcts can b vntually dividd into discrt, small particls, byond which mattr is no longr cuttabl yt our rsarch in th past cntury has provn just th opposit! No, Or mayb th Grks ar corrct!

12 Look mor into mattr, ar thr mor layrs byond uarks and lptons? Ys, sinc our ust for th structur of mattr sms to continu indfinitly. It is hard to bliv that nothing happns btwn 10-18m and th Planck scal (10-35m). No, bcaus th Standard Modl is a rlativistically corrct uantum fild thory. Thrfor, nothing can happn until th Planck scal, whr QFT itslf braks down along with th concpt of continuous spac. thrfor: uarks and lptons must hav an intrinsic siz at th Planck scal. my answr: it has to b this way, othrwis w will find an infinit numbr of nw intractions, at highr and highr nrgy scals!

13 How should w procd? Look mor into math Can th symmtris b unifid? (Grand unification thory); Can thr b highr lvls of symmtris (suprsymmtry)? look for nw phnomna prdictd by GUT. Look mor into mattr, ar thr mor layrs byond uarks and lptons? lpton and uark compositnss Look mor into xisting discrpancis muon g-2, proton radius, dark mattr (sarchs) masur thm to highr prcision! but can b cloudd by xprimntal systmatics, or th ability to xprimnt! Try to find nw discrpancis by masuring physical uantitis to high prcision rar dcays, univrsality, EDM, prcision PVES Look for nw particls, nw phnomnon, forbiddn procsss tc a littl hardr, sinc it may not b clar whr to look (th simplst xtnsion to SM would b anothr U(1) group/symmtry, a lptophobic Z... )

14 Try to find nw discrpancis by masuring physical uantitis to high prcision rar dcays, univrsality, EDM, prcision PVES Th lctrowak mixing happns in th nutral wak intractions. Thrfor, nutral wak procsss provid a rick playground for SM physicists! This is th rol w play with PVES.

15 Standard Modl Prdictions for PVES Unlik lctric charg, nd two chargs (couplings) for wak intraction: gl, gr or vctor and axial wak chargs: gv~(gl+gr) Z0 ga~(gl-gr)

16 Standard Modl Prdictions for PVES Unlik lctric charg, nd two chargs (couplings) for wak intraction: gl, gr or vctor and axial wak chargs: PVES asymmtry coms from: V-A -V-A gv~(gl+gr) Z0 V-A -V-A ga~(gl-gr) lctron-uark ffctiv couplings and can b dirctly rlatd to sin2 W

Bst Data on C1 (AV) and C2 (VA) couplings from PVES E122 0.2 bfor Qwak 2C2u-C2d 0.

17 Bst Data on C1 (AV) and C2 (VA) couplings from PVES E bfor Qwak 2C2u-C2d HallA (2014) all data (2014) C1u-C1d

18 Sarching for Nw Contact Intractions Blow th mass scal : such nw physics will manifst itslf as nw ll-typ 4-frmion contact intractions, that modify th valus of C1 and C2 from thir Standard Modl prdictions. V-A -V-A V-A -V-A Z0 V-A -V-A V-A -V-A Erlr&Su, Prog. Part. Nucl. Phys. 71, 119 (2013)

19 Limit on nw lctron-uark AV and VA contact intractions nw physics xcludd from th rd rgion

20 Contact Intraction Limits from LHC (PDG) Collidrs masur combinations of (VV+AA+AV+VA), no individual accss to AV or VA trms! PVES is complmntary to collidr sarchs

21 Mollr and SoLID PVDIS

22 Th Standard Modl is a vry succssful thory up to th lctrowak scal. Evidnc xists for thoris byond th Standard Modl, but th argumnts oftn ar philosophical. Thr ar many ways to look for brakthrough. Among thm, prcision masurmnts of physical constants (coupling constants, for xampl) provid an ffctiv way to sarch for possibl dirctions whr physics byond th Standard Modl may b found. Parity violating lctron scattring provids a crucial tool to tst th SM in th EW sctor. W at JLab hav don a good job on this topic (carrying th torch ovr from SLAC), and w hav a plan to continu in th 12 GV ra. Ar w going to s dviation from th SM? Probably not, but that s not why w do it. Stay tund!

DIS-Parity. Search for New Physics Through Parity Violation In Deep Inelastic Electron Scattering. The Physics Case

DIS-Parity. Search for New Physics Through Parity Violation In Deep Inelastic Electron Scattering. The Physics Case DIS-Parity Sarch for Nw Physics Through Parity Violation In Dp Inlastic Elctron Scattring Th Physics Cas R. Arnold for th DIS-Parity Collaboration Exprimnt Plan by Stv Rock will follow 12 Jun 2003 DIS-Parity