1 / 23

Top physics at the

Top physics at the. LHeC workshop 20 th january 2014. Olaf Behnke (DESY). t. Single top production Top pair production. t. t. 1. Single T op production in charged currents. 5-flavour scheme. Determine V tb from cross section Check for anomalous production

celine
Download Presentation

Top physics at the

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Top physics at the LHeC workshop 20thjanuary 2014 Olaf Behnke (DESY) t • Single top production • Top pair production t t 1

  2. Single Top production in charged currents 5-flavour scheme • Determine Vtb from cross section • Check for anomalous production • Depending on (sensitive to) effective b-quark density in proton 2

  3. Single Top production in charged currents 5-flavour scheme • Determine Vtb from cross section • Check for anomalous production • Depending on (sensitive to) effective b-quark density in proton Can be determined in situ from F2bb measurements at LHeC ! 3

  4. Studies with Madgraph 5 generate e- p > ve t~ Madgraph parameters used throughout • Collider scenario: 7 TeV p on 60 GeV electrons • So far only on parton level • Standard madgraph cards (e.g. CTEQ6L1) • 5-flavour scheme 4

  5. Studies with Madgraph 5 generate e- p > ve t~ Obtained total LO Cross Section: 1.8 pb Check in the following slides the decay kinematics (is it within the LHeC detector?) 5

  6. Pt(b) X-sect=7.354E-01(pb) AVG=5.878E+01 RMS=2.330E+01 Tot#Evts= 21406Entries= 21401Undersc= 0Over Typical LHC cut (ATLAS, CMS) 6

  7. Pt(e) X-sect=7.354E-01(pb) AVG=4.038E+01 RMS=2.018E+01 Tot#Evts= 21406Entries= 10728Undersc= 0Over Typical LHC cut 7

  8. y(b) X-sect=7.354E-01(pb) AVG=-1.184E+00 RMS=1.047E+00 Tot#Evts= 21406Entries= 21395Undersc= 11Over Typical LHC cut 8

  9. y(e) X-sect=7.354E-01(pb) AVG=-5.546E-01 RMS=8.752E-01 Tot#Evts= 21406Entries= 10728Undersc= 0Over Typical LHC cut 9

  10. Conclusion from kinematic studies on charged current Single Top production • Majority of events is within the anticipated LHeC detector acceptance. 10

  11. CC Single Top at LHeC compared to LHC s-channel t-channel tW-channel tt prod. LHC 4.6 64.2 15.7 163 s @7TeV (pb) (NNLO Kidonakis) LHeC s (pb) (LO Madgraph) ~0.01 in DIS 1.8 0.0029 ~10000 2900 1.8M  Expected #events for 1000 fb-1 11

  12. CC Single Top at LHeC compared to LHC s-channel t-channel tW-channel tt prod. LHC 4.6 64.2 15.7 163 s @7TeV (pb) (NNLO Kidonakis) LHeC s (pb) (LO Madgraph) ~0.01 in DIS 1.8 0.0029 ~10000 2900 1.8M  Expected #events for 1000 fb-1 12 Available for precise Vtb determination

  13. CC Single Top: Status of Vtb at LHC GeorgioChiarelli, arXiv:1302.1773  Further detector level studies are needed to assess the LHeC potential for Vtb (Acceptance, Backgrounds from W production etc.) 13

  14. FCNC Anomalous Single Top production • Extremely suppressed in SM • Potential window to BSM Study by G. Brandt (LHeC 2008 workshop, Divonne) Using anotop MC with Kutg=0.01:  Expect for 7 TeV x 70 GeVLHeC with 1000 fb-1 7600 FCNC top events But large backgrounds from SM W and CC single top Better prospects at LHeC-based gp collider mode, see LHeC CDR, p.205 14

  15. Top pair production in DIS at LHeC • Sensitive to the proton gluon density at high x Madgraph LO Cross Section: 9.9 fb Expect more from photoproduction (not simulated yet) 15

  16. Top pair production in DIS at LHeC Kinematics Forward to very forward production 16

  17. Top pair production in DIS at LHeC Kinematics Corresponds to ~1500 fb-1 With L=1000 fb-1 expect some tens of events produced at high x >0.5 17

  18. Top pair production in DIS at LHeC Kinematics with final state cuts Corresponds to higher L t-> bln, t~-> bln pt(b)>10 GeV, pt(l)>10 GeV y(b)<3.0 y(l)<3.0 Total kinematic acceptance ~50%, high x somewhat suppressed 18

  19. Conclusions on top at LHeC • Study top production for the first time at an ep collider  is a unique test of the SM • Single Top production in charged currents: Expect precision measurement of Vtb • Top Pair production in DIS and photoproduction: clean test of proton gluon density at high x(but suffers from rather low statistic) • In general: sensitive tests of new physics through anomalous production channels/cross sections • Further studies at detector level needed (including background simulation) for detailed assessment of physics potentialfor top production and decays 19

  20. Backup slides

  21. Top physics at the LHeC workshop 20thjanuary 2014 Olaf Behnke (DESY) • Single top production Wb t, gb  tW, FCNC gu t • Top pair production gg t t~ 1

  22. The Detector ‘that should do it’: Ring-Linac scenario Outer detectors (HAC tailcatcher/muon detectors not shown)also not shown: forward proton taggers, backward lumi monitors 20

  23. Missing ET X-sect=7.354E-01(pb) AVG=5.730E+01 RMS=2.992E+01 Tot#Evts= 21406Entries= 21402Undersc= 0Over 3

More Related