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v3.3.5-pre
Date/Time: 10:30~17:30 JST, June 13, 2015
Place: Room 425, Building No.3, KEK
Official Language: English
Video Conference ID: 437 (KEK MCU2)
Fuze connection: http://fuze.me/29340610
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A Summary of The 42nd General Meeting of the ILC Physics Subgroup
June 13, 2015 (Sat) at Room 425, Building 3, KEK
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0) Attendants:
Present at KEK:
A.Ishikawa (Tohoku)
K.Fujii (KEK)
J.Tian (KEK)
J.Yan (KEK)
T.Ogawa (Sokendai)
M.Kurata (Tokyo)
D.Jeans (Tokyo)
K.Hidaka (Tokyo Gakugei)
J.Strube (PNNL)
Remote connection:
T.Tanabe (Tokyo)
S.Kawada (Hiroshima)
K.Ikematsu (Saga)
Y.Sudo (Kyushu)
T.Tomita (Kyushu)
T.Suehara (Kyushu)
0) Opening comments (K.Fujii)
1) Leptonic recoil mass analysis (Jacqulline Yan)
Status:
Improvements since the last meeting:
Z->ee in addition to Z->mm
all Ecm
both xsec and mh measurements
improved selection to minimize bias
better fitting technique (use of Kernel function for signal)
Dominant BG:
ZZ (llX), gamma Z (gamma ll), WW (llvv)
New cuts:
vector pt sum (dl+gamma)
cos(theta_missing) (applied only when an energetic gamma is there)
Cross section measurements:
Ecm=250GeV
(-0.8,+0.3) 2.7% 38MeV
(+0.8,-0.3) 2.9% 38MeV
Ecm=350GeV
(-0.8,+0.3) 3.2% 97MeV
(+0.8,-0.3) 3.6% 105MeV
Ecm=500GeV
(-0.8,+0.3) 5.0% 450MeV (BG fit with wider window)
(+0.8,-0.3) 5.3% 540MeV (BG fit with wider window)
The results above are with fixed BG.
If we float BG, xsec error is 10% worse.no effect on mh.
BG fluctuation is about 1%.
Checked selection bias -> confirmed model-independence
C: acceptance hole must be covered LumiHCAL
Next Step:
- increase MC statisitics
- ZZ fusion analysis (Zee)
- semi-model independent analysis
visible and invisible Higgs separately.
2) Plan by Next weekend & some trials (Masakazu Kurata)
Status:
- ilcsoft v01-17-07
Particle ID modules
- new jet clustering
Particle ID:
implementing requests from Jenny: getType(), getPDG(), getLikelihood(), …
vector of posterior probabilities for different hypothsis.
Jet clustering
DICLUS: dipole jet clustering
3->2 process, all the other algorithms are 2->1.
-> tried this starting from 20 jets by Durham.
-> so far no significant improvements seen for the qqbbbb sample
Separation of quark and gluon jets
jet broadening
-> For 20 jets by Durham,
Next Step:
- Polish up PID module for v01-17-07
- For top WS, study/improve LCFIPlus.
- For software WS, clean up and make the code public.
3) Anomalous HVV couplings (Tomohisa Ogawa)
Status:
Anomalous HVV couplings:
SM-like, FF, FFtilde
Zh production:
Observables:
- production angle of Z
- delta phi (angle btw production and decay planes of Z)
- sigma_Zh
Update on analysis based on the recoil mass technique
mmh and eeh
Event selection
try to avoid any cuts on Z angles
-> acceptance function much improved.
efficiency ~ 0.8 for mu
~ 0.7 for e
-> contour plots obtained for a, b, and bt.
Next Step:
- Improve selection: better lepton finder.
- Require h->bb and see how it affects the precision.
4) H->tau tau (Daniel Jeans)
Status:
It is the first report on a new project.
Physics target: Higgs CP study,..
tau decay BR:
~11%: pi+ v -> this talk
~25%: pi+ pi0 v
~35%: l+ v v
Kinematical reconstruction of taus from thier pi+/- v decays
250GeV Whizard 2.2.2 with private Tauola interface.
1st approach:
MarlinKinFit
-> found that the initial neutrino momentum is very important
for convergence of the fit.
2nd approach:
Try to calculate unknowns.
-> find neutrino momentum in the plane spanned by the PCA vector
and pi+ momentum.
-> 4 solutions per event.
-> choose the best by making the overall pt as small as possible,
by comparing |pz| and Emis, and by looking at m_tautau.
Next Step:
- apply kin. fit for identified solution.
- apply to tau->rho v decay.
- Higgs CP measurement.
5) Off-shell Higgs contribution, new jet culustering (Junping Tian)
Status:
Off-shell H decay used to constrain Gamma_h at LHC.
This talk:
ZH*->ZWW at ILC
-> off-shell/on-shell ~ 3%
Similar investigation about vvWW and vvtt
-> seems to be the off-shell H contribution can be ignored
in the recoil mass measurements.
New jet-clustering
Potential impact on HHH coupling:
40% if we have perfect color-singlet clustering.
We know that Durham is correct till 20 mini-jets.
idea is to assign at this level the probability using parton shower PDF.
Next Step:
- check the 20 min-jets are really partons.
- construct likelihood for parton showering
6) Top Yukawa coupling study at 500 GeV (Yuji Sudo)
Status:
500GeV (500fb-1), (-0.8,+0.3)
Updates
K-factor (0.843) applied to the signal.
Updated 6f xsec values using DBD official values.
Improve 6f event shape.
Try BDT.
Results
(-0.8,+0.3) 2.17 (8j) -> 1.93
2.00 (l6j) -> 1.72
1.02 (2l2j -> 0.88
TMVA: 1st try suggests that we might get ~20% improvement.
C: It seems to be overtrained.
There still seems to be some inconsistency in cross section estimates
between physsim (tbW) and Whizard (6f).
Next step:
- Resolve the problem with the cross section estimates.
- Increase BG statistics.
- Then TMVA.
7) ZH: Recoil mass using Z->qq (Tatsuhiko Tomita)
Status:
Update: added new categorization according to #jets.
jet-clustering using fixed y-cut (difference from Mark’s analysis)
ZH->qqH @250GeV (250fb-1)
Decay mode dependence:
after categorization
deviation from the mean efficiency < 3.5% (sigma. stat)
except for h->invisible, gg (~5%)
Results:
(-0.8,+3) : delta sigma / sigma = 2.7%
(+0.8,-3) : delta sigma / sigma = 2.4%
-> 5% BR change produces only ~0.5% effect on xsec.
ZH->qqH @350GeV (333fb-1)
Decay mode dependence:
after categorization
deviation from the mean efficiency: >8% for h->gg
maybe y-cut is too small.
Results:
(-0.8,+3) : delta sigma / sigma = 3.1%
(+0.8,-3) : delta sigma / sigma = 3.1%
nees more effort.
Next Step:
- 500GeV by new student.
- 350GeV also. -> There is much room for improvements.
-> tuning of y-cut value.
C: H20 requires a reasonable gHZZ measurement at 500GeV.
8) Discussions: all
See slides by Junping.
1) Higgs analysis
Recoil mass at 500GeV, now very important for H20
New student for hadronic recoil at 500GeV
Jaqueline for leptonic recoil at 500GeV
h->tau+tau-
Daniel (CPV)
Comprehensive hVV anomalous coupling study with various modes
Ogawa
h->WW*
Ono, Junping, Ogawa
h->gamma gamma, mu mu
Tino
tth
Yuji
self-coupling
Claude, Junping, Kurata
ttbar threshold
Ozawa (Tohoku, new student)
2) BSM
gamma DM DM
Tomohiko
EWkino with 15 GeV mass difference
Fast simulation parameter scan (M1, M2, mu)
2-fermion processes
Flavor violating decays of h
h-> mu tau, b s
H+H-, HA
Abhinav left the group.
smu-stau
3) Systematic uncertainties
W mass: Tsuchimoto
Beam spectrum effect:
Jacqulline for recoil mass
Ozawa for ttbar threshold
Flavor tagging
…
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The slides shown at the meeting is available from
https://agenda.linearcollider.org/event/6793/
see them for details.
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*) Meeting Schedule:
Next general meeting (2015/09/05 10:30) : Conf.ID: 603
Working group web page:
http://www-jlc.kek.jp/jlc/en/subg/physics