Download presentation

Presentation is loading. Please wait.

Published byMonica McCracken Modified over 2 years ago

1
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 1 Non-SUSY Searches at HERA Peter Schleper Hamburg University SUSY07 July 27, 2007 HERA Performance Model –independent Search Contact Interactions Excited Fermions

2
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 2 1. HERA Perfomance HERA– I : 1992 - 2000 ~ 120 pb -1 per experiment, mostly e + p HERA– II: 2003 - 2007 Upgrade: luminosity & polarisation: e L -, e R -, e L +, e R + Recently: very good conditions low background, stable beam conditions high data taking efficiencies, low thresholds no major problems on central detectors polarisation average ~ 40% electron & positron running ~184 pb -1 e - p ~294 pb -1 e + p Luminosity HERA I & II ~ 478 pb -1 per experiment, ~ 90 % at 320 GeV End of HERA running in June, 2007 final data set Polarisation Luminosity

3
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 3 HERA Data ~ few 10 8 ep collisions triggered by H1 & ZEUS Thresholds: 5 … 10 GeV for electrons and jets Luminosity: ~ 1.6 …3.5 % precision Polarisation: ~ 3... 5 % precision Calorimeters E-scales: 1 … 3 % for e, jets from kin. Constr. Neutral CurrentCharged Current Inclusive Jet Production Q2Q2 Polarisation Q2Q2

4
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 4 2. Model – independent Search (H1) Inclusive search for particles at high P T Electrons,Photons, Muons, Hadronic Jets, Neutrinos (PTmiss) phase space for all: P T >20 GeV 10 o < θ < 140 o All combinations: ee, e ,e ,ej,….jj, ejj, ej event classes Mass and ∑P T (Jacobi-peak) Comparison to SM (LO) look for deviations (max. deviations) Statistical interpretation via monte carlo experiments probability

5
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 5 Model – independent Search Event Classes

6
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 6 Model – independent Search Precision : Systematics: few % Statistically limited at large M, PT and large multiplicity Theory: uncertainty large for multi-jet channel Distribution for data follows expectation Excellent understanding of most final states at HERA Exception: Largest deviation for j channel e + p: H1 observation: 21 / 8.9±1.5 events (3.0σ) ZEUS: no events in excess of SM e - p: H1 and ZEUS: Agreement with SM Dedicated search: talk by J. Katzy Probability of max. deviation for event classes

7
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 7 3. Contact Interactions (ZEUS) Standard Model + 4-Fermion interaction Compositeness Quark radius Leptoquark (M> E CMS ) Squarks in R P -viol. Large Extra Dimensions

8
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 8 Contact Interactions Measurement via 2-angle method: Resolution << Binning Results limited by statistics

9
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 9 Contact Interactions Typical Range of Contact Interaction scales: 2 … 7.5 TeV Improvements: Luminosity: factor 2 Polarisation Q2Q2 Q2Q2 Helicity Combinations Data / SM

10
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 10 Leptoquarks (indirect) Leptoquark masses excluded for: Indirect search M / λ‘ > 0.3 … 2 TeV Direct searches for peak in M eq M<300 GeV λ < 0.01 Squarks in R-parity viol. SUSY: λ‘ ijk L i Q j D k coupling u has same coupling as S 1/2 same limit applies ~ ~

11
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 11 Large Extra Dimension LED’s limited to M S > 0.88 TeV Quark Radius limited to R q < 0.67 x 10 -18 m Q2Q2 Q2Q2

12
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 12 4. Excited Leptons (H1) Resonance production for masses < E CMS f* f V fVfV compositeness scale f, f ’ relative strength for W , B , Z Effective lagrangian to parameterize compositeness: Spin ½, isospin ½, vector currents as SM leptons

13
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 13 Excited electrons Full statistics: No excess seen

14
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 14 Excited Electrons and Neutrinos HERA: Limits typically 220 … 280 GeV for M ~ / f LEP: M > 208 GeV direct search LEP/Tevatron: indirect limits for M > 280 GeV

15
Peter Schleper, Hamburg University SUSY07 Non-SUSY Searches at HERA 15 5. Conclusion HERA: final statistics available 0.5 fb-1 per experiment Precision limited by Luminosity for indirect searches: Contact interactions Beam energies for direct searches Experimental errors small in most cases Model –independent search (H1 full statistics): Few % level of understanding of ~ ALL final states at HERA Exception: H1: j channel for e+ scattering ZEUS: not confirmed Contact interactions (ZEUS 285 pb -1 ): limits on scale ~ 10 x E CMS … up to 7.5 TeV Improvements from luminosity and polarisation still to come Excited Leptons (H1 full statistics): Mass limit ~ 220 … 280 GeV

Similar presentations

OK

16/17 August 2005 Tobias Haas: HERA II An Introduction to HERA Physics DESY Summer Student Program 16/17 August, 2005 Tobias Haas DESY, Hamburg.

16/17 August 2005 Tobias Haas: HERA II An Introduction to HERA Physics DESY Summer Student Program 16/17 August, 2005 Tobias Haas DESY, Hamburg.

© 2017 SlidePlayer.com Inc.

All rights reserved.

Ads by Google

Stem and leaf display ppt on tv Ppt on non biodegradable wastes Ppt on writing summary Ppt on ac to dc rectifier circuit Ppt on game theory examples Ppt on human resources information system Ppt on child labour in world Ppt on amplitude shift keying graph Ppt on film industry bollywood dance Export pdf to ppt online