Higgs & Top at LHeC

Monday 29 Aug 2016, 11:00 → 13:00 Europe/Zurich

CERN

CERN - Tokyo - Liverpool - Johannesburg - Beijing - Hamburg

Satoshi presented updates on invisible Higgs search.
He optimized the cut-based selections, and the 2-sigma sensitivity
improved from 7.25% to 6.00%.  Furthermore, by adding number jet cut
(N_j=1), it improved to 5.96%.  For the MVA selection, the optimum cut
(score>0.2) gives the sensitivity of 5.09%.
Chen asked about tau-veto, since it is a significant background from W events.
He also pointed out the importance of looking at photoproduction background.
Kechecn suggested to include N_j cut in the preselection of MVA selection.

Tanaka-san reported on the status of Hbb coupling measurement.
The effect of electron tagging bug in Delphes card 3.1.2 was checked.
Some background increased and small decrease of signal was observed,
but the statistical precision of coupling measurement changed marginally,
from 0.0095 to 0.0096.  So the effect on CC channel was small.
 

Orhan Cakir:
Orhan presents new studies about
Probing Top Quark FCNC in gamma p Collisions at ep Colliders
with Detector simulation, where the following things are new:
- Cross section calculation and event generation with MG5,
with scan for lambda_()L/R) =-0.1 : 0.1
- Signal+background for W+j (where j=u,d,s,c,b and anti-quarks)
- For detector simulation they use Delphes detector card,
ATLAS card for LHeC , and FCC card for FCC-ep, tried LHeC det. card.
- Plot invariant mass M(3j) of three-jets,
one is tagged as b-jet, other two are light jets
- Top mass and W mass reconstruction, with
preselection cuts + cuts-1/2/3/4/5
- For a question about S/B line colour in inv. mass plots
Ali talked on the inversion of colours in slide 9.
- Cut efficiencies plot, significance plot
- They compare the cases for
laser and epa spectrum in photon-proton collisions.
- Luminosity need for 3 sigma,
they find a sensitivity to λ=0.005 for Lint=15/fb
in γp collisions at LHeC(laser) with Ee=60 GeV, Ep=7 TeV.
- and a sensitivity to λ=0.01 for 25/fb in γp collisions
at FCC-ep(laser) with Ee=60 GeV, Ep=50 TeV.

They will continue to the study:
- try to improve reconstruction at low lambda
- comparison the results with previous study
- discussion on gamma p luminosity
- preparation of a Note

11:00 → 11:10 Update on invisible decay study

Speaker: Satoshi Kawaguchi (Tokyo Institute of Technology (JP))

August_29th.pdf

11:10 → 11:20 Hbb coupling measurement

Speaker: Masahiro Tanaka (Tokyo Institute of Technology (JP))

2016_08_29.pdf

11:20 → 11:30 Hbb and Hcc using jet lifetime probabilities

Speaker: Uta Klein (University of Liverpool (GB))

11:30 → 11:40 Single top analysis

Speaker: Xifeng Ruan (University of the Witwatersrand (ZA))

11:40 → 11:50 Status of Wits Studies

Speaker: Mukesh Kumar (University of the Witwatersrand (ZA))

11:50 → 12:00 FCNC top-Higgs couplings

Speaker: hao sun (DaLian University of Technology)

12:00 → 12:10 Probing Top Quark FCNC in gamma p Collisions

Speakers: Orhan CAKIR (Ankara University), Orhan Cakir (University of Ankara), Orhan Cakir (University of Ankara (TR)), Prof. Orhan Cakir (Ankara University (TR)), Orhan Cakir (University of Ankara (TR))

TOPFCNC_EPPPGP_V4.pdf