DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches1 Electroweak Physics + Searches Andrew Mehta DIS 2003, St. Petersburg, April 2003

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches2 Contents Only a small personal selection of many many results - only collider experiments. Details in parallel sessions. New Electroweak results Search for SM Higgs Search for MSSM Higgs R Parity violating SUSY searches 2  +E TMISS from Tevatron W+  from Tevatron Leptons + E TMISS from HERA Search for single top from HERA Leptoquarks Large extra dimensions Dijets from Tevatron Dileptons from Tevatron Search for magnetic monopoles

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches3 Status of Experiments LEP (e + e  pp  s<209 GeV) - Final run Dec Many final data published eg. Higgs search. Tevatron (pp  s=196 GeV) - Run II underway after slow start. About 100 pb -1 per experiment so far (same as Run I). Many new results. Most not yet competitative with Run I, but soon will overtake them HERA (ep  s=319 GeV) Run I (120 pb -1 per experiment) completed. Many final Run I results presented. Run II start up slow. High luminosity and polarisation demonstrated. Awaiting luminosity in summer 2003

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches4 Tevatron RunII EW Results Z  e + e - W  e

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches5 W Mass Measurements DIRECTDIRECT INDIRECTINDIRECT

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches6 New M top Measurements 179 ± 3.6 ±6 GeV (D0 Run I Preliminary) 171.2±13.4± 9.9 GeV (CDF Run II Preliminary) Old Value ± 5.1 GeV (CDF+D0 Published) New more accurate D0 Run I result First results from Run II –more data needed + better calibrations

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches7 Impact of Tevatron RunII Expected Run II Can constrain Higgs Mass from Tevatron alone.

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches8 World Electroweak Results Maximum deviation 2.94 sigma!

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches9 Higgs Limits from EW Data M H <211 GeV (95% CL) (Does not include latest top mass measurements) Result not affected much by NuTeV deviation

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches10 Direct Higgs Searches at LEP Data now final (cern-ep ) No large deviations of data seen in mass Spectrum

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches11 Direct Higgs Searches at LEP Excess around 99 GeV not relevant for SM Higgs (MSSM though?). No significant excess at 115 GeV in final LEP data

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches12 Direct Higgs Searches at LEP No Higgs seen at LEP M H <114.4 GeV (95% CL) Tevatron II EXPECTED search potential M H  110 GeV (2 fb -1 ) M H  130 GeV (6.5 fb -1 )

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches13 Higgs Sector of MSSM Two Higgs doublets. CP conserved Physical Higgs bosons: h and H (CP even), A (CP odd), H  Processes at LEP: Search rather similar to Standard Model Higgs

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches14 MSSM Higgs Search 2  excess at m h  97 GeV No strong evidence. Limits m A, m h >  90 GeV (depends on model)

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches15 R p violating MSSM from HERA R parity =1 for known particles = -1 for supersymmetric partners R p violation  SUSY particles can be singly produced & LSP not stable LQ like Cascade decays No excesses seen in any channel  set limits.

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches16 R p violating MSSM from HERA Unconstrained MSSM - free variation of , M 2, tan 

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches17 Search for 2  +E T Miss Tevatron Remember CDF event? Search in RunII data CDF+D0 No events at large E T Miss No event with an additonal lepton (yet!) Cross section limit <0.9 pb DØ Run II Preliminary E T Miss

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches18 2e2  +E T Miss Event from Run I Event still unexplained by SM processes (10 -6 events expected)

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches19 Search for W+photon Run I: Et>25 GeV, lepton Et>25 GeV, photon Et>25 GeV leptonDataSM exp muon114.2 electron53.4 both167.6 Excess seen in CDF Run I data Excess not seen in Run II

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches20 Leptons+ P T Miss from HERA Look for isolated lepton + missing P T Only significant SM process is W production: Example event X Lepton P T Miss NLO SM W calculations now available Deiner et al. (hep-ph/ )

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches21 Leptons+ P T Miss at HERA H1 e+ , e + data, published Data SM prob P T X < 25 GeV P T X > 25 GeV ZEUS e+  + , e  data No taus yet Data SM prob e+ , published P T X > 25 GeV , preliminary P T X > 25 GeV Excesses seen at large P T X - region most likely for new physics

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches22 Leptons+ P T Miss at HERA Discussion H1 sees excess in electron and muon channel H1 excess first seen in data H1 excess also seen in data ZEUS see no excess in electron or muon channels ZEUS see an excess in tau channel All together 19 data events SM 8.8 ( prob % assuming systematic error 15 % ) Q. Why does the SM expectation vary so much? A1. Main reason for H1/ZEUS difference is a larger non-W component in ZEUS data. A2. Tau channel has much lower efficiency due to harsh cuts to suppress CC background  Not enough statistics for firm conclusion, need more data

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches23 (Aside) Top from Tevatron Jet l-l- l+l+ p p Jet Top search results in very similar final state to HERA events. Any excess found in top analysis may be due to same process

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches24 Search for single top at HERA Anomalous single top production could explain lepton+P TMiss Search possible in hadronic channel also SM rate negligible due to FCNC vertex tu  t t Jet

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches25 Anomalous tu  Coupling HERA-assume iso. lep. events are SM fluctuations and set limits on anomalous coupling LEP+Tevatron sensitive too  complementary results from all 3 experiments

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches26 Leptoquarks Tevatron Quarks and Leptons have many symmetries : (3  2) proton and electron charges equal Is there a higher symmetry? Leptoquarks with B  0, L  0 LQs appear in many GUTs Buchmüller-Rückl-Wyler model predicts 14 LQs (7 scalar, 7 vector) - F=0 for e + q, F=2 for e - q Yukawa coupling. BR fixed  eq =1, 0.5,  q =0, 0.5 HERA

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches27 Leptoquarks Data from HERA No excess seen  place limits

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches28 Leptoquarks Tevatron run II data give similar limits to run I

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches29 Rutherford scattering off a Quark At very high 4 momentum transfer DIS at HERA probes distances 1/1000 th size of proton If the quarks had substructure the DIS cross section would be modified Quarks have radius <0.7  cm

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches30 Large Extra Dimensions in DIS Arkani-Hamed, Dimopolos & Dvali sugggest gravitons propagate in 4+n dimensions (PLB 544 (1988) 263). Extra dimensions curled up within size R, M pl 2 ~ R n M s n+2 M s is thought to be of order m ew  n=1 R ~ solar system n=2 R ~ 1 mm In DIS virtual graviton exchange effects eq  eq’ No deviations found Limits of M s >0.8 TeV

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches31 Large Extra Dimensions at LEP Similar effect at LEP (Interference with t channel ee  ee) Combined LEP limit M s >1 TeV

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches32 DiJets from Tevatron

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches33 DiJets from Tevatron Many models produce such particles Masses up to 840 GeV ruled out

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches34 DiLeptons from Tevatron Good description by SM

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches35 Limits for Sequential Standard Model Z' DiLeptons from Tevatron Same data used for other constraints eg. Graviton mass in LED model

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches36 Search for Magnetic Monopoles strip Solenoid ( = 1 g d ) i Method cut beam pipe into strips and pass through solenoidal field Mimic monopole by attaching a solenoid to one end of strip Current induced in solenoid measured in SQUID magnetometer Dipoles currents return to original value Monopole signal shows a current increase Monopoles should be stopped in beam pipe and remain

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches37 Search for Monopoles No monopoles seen  set limits

DIS 2003, May 22-27, St PetersburgAndrew Mehta Electroweak Physics and Searches38 Conclusions  Nearly final electroweak results from LEP now available. Still no explanation of 2.94 deviation by NuTeV.  New techniques being developed at Tevatron to reduce error on top & W masses  LEP definitely did not see Higgs  Tevatron run II well underway - many first search results  Looking forward to HERA run II data  No evidence for physics beyond the standard model. Some interesting hints though - run II data HERA+Tevatron needed