Choose timezone
Your profile timezone:
Powered by Indico
v3.3.5-pre
Date/Time: 10:30~17:30 JST, Apr. 11, 2015
Place: Room 425, Building No.3, KEK
Official Language: English
Video Conference ID: 742 (KEK MCU2)
Fuze connection: http://fuze.me/28522210
--------------------------------------------------------------------------------
A Summary of The 40th General Meeting of the ILC Physics Subgroup
Jan. 24, 2015 (Sat) at Room 425, Building 3, KEK
--------------------------------------------------------------------------------
0) Attendants:
Present at KEK:
A.Ishikawa (Tohoku)
S.Watanuki (Tohoku)
K.Fujii (KEK)
J.Tian (KEK)
M.Nojiri (KEK)
Y.Okada (KEK)
T.Ogawa (Sokendai)
T.Tanabe (Tokyo)
M.Kurata (Tokyo)
K.Hidaka (Gakugei)
Remote connection:
J.Yan (KEK)
H.Ono (NDU)
S.Kawada (Hiroshima)
Y.Sudo (Kyushu)
T.Tomita (Kyushu)
T.Suehara (Kyushu)
0) Opening comments (K.Fujii)
1) Leptonic recoil mass analysis (Jacqulline Yan)
Status:
Cross section measurements:
Ecm=350GeV
(-0.8,+0.3) 4.0% (19% improvement from AWLC2014)
(+0.8,-0.3) 4.4% (12% improvement from AWLC2014)
Ecm=250GeV
(-0.8,+0.3) 3.3% ( 8% improvement from AWLC2014)
(+0.8,-0.3) 3.5% (-6% improvement from AWLC2014)
Key improvements:
Use of likelihood cut, better isolated lepton finder
Use of Econe info. around most energetic photon
Check of decay mode independence:
dptbal cut might bias h -> tau+tau-
-> total bias < 0.5%
Acceptance hole:
5-8 deg. <=> ECAL endcap and LumiCal
Next Step:
- further improve the precision while minimizing bias
- Zee channel
C: Reexamine the mass fit range, since off-shell h* to on-shell WW
will open at mh=160GeV, which is not included in the current MC.
2) ZH: Recoil mass using Z->qq (Tatsuhiko Tomita)
Status:
ZH->qqH @250GeV (250fb-1)
Decay mode dependence:
after categorization
deviation from the mean efficiency < 3.2% (sigma. stat)
except for h->gg, cc (~5%)
Results:
(-0.8,+3) : delta sigma / sigma = 3.3%
(+0.8,-3) : delta sigma / sigma = 3.1%
-> even in worst case, stat error < 5%.
Next Step:
- Improve the bias due to efficiency differences.
- 350GeV
- Invisible decay.
3) Top Yukawa coupling study at 500 GeV (Yuji Sudo)
Status:
500GeV (500fb-1), (-0.8,+0.3)
Updates
lepton ID is now based on BDT
Increase MC stat. (at least x2)
tth -> 2l2lv+4b
re-optimization of event selection.
Results
(-0.8,+0.3) 2.17 (8j)
2.00 (l6j)
1.02 (2l2j
(+0.8,-0.3) 1.40 (8j)
1.29 (l6j)
0.72 (2l2j
-> combined results:
delta y_t/y_t = 16.6%
Ecm dependence:
delta y_t/y_t = 9.9% @ 500GeV (500fb-1)
Next step:
- Increase further tbW MC stat.
C: Try TMVA loosening y-value cut, for instance to keep tbW statistics.
4) Self-coupling & h->invisible (Junping Tian)
Status:
Current state-of-the-art of hhh measurements:
500GeV(1.6ab-1) 46% -> 29% (4ab-1: new running scenario)
1TeV (2.5ab-1) 13%
What happens if lambda > SM as in EW BAU scenario:
lambda -> +100% -> Not only sigma_Zhh goes up
but also sensitivity factor improves!
-> delta lambda / lambda = 14% -> 7-sigma discovery.
Zhh and vvhh compensate each other!
h->invisible using Z->l+l-
95%CL upper limit on BR(h->inv.)
250GeV (-0.8,+0.3) 2.02%
250fb-1 (+0.8,-0.3) 1.28%
350GeV (-0.8,+0.3) 2.05%
330fb-1 (+0.8,-0.3) 1.78%
500GeV (-0.8,+0.3) 3.64%
500fb-1 (+0.8,-0.3) 2.64%
The measurements seem quite useful in particular at higher Es.
5) 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
eeh production:
Observable:
- delta phi (azimuthal angle difference between final state e+ and e-)
Preliminary results shown for expected a, b, bt limits.
Next Step:
- Fix the bug in Z->ee analysis.
- Investigate the funny structure in the acceptance.
C: Check the reconstructed delta phi distributions.
6) WIMP searches using mono-photons (Tomohiko Tanabe)
Planning:
Tomohiko discussed the plan for WIMP search feasibility studies
using effective operator approach.
Possible new studies:
- EWkinos with 15 GeV mass difference
- 2-fermion processes.
7) Self-couplings, analysis techniques (Masakazu Kurata)
Status:
Improvements:
Jet paring using Bayesian approach
60.2% (chi2) -> 75% (Bayes) for WW->jjjj
Kinematical fit
Try Zhh -> (bb)(bb)(lvjj) first.
Important to take into account Ejet resolution in the fit
-> introduction of Gumbel distribution for PDF.
-> significant improvement in mh. -> promising.
MVA on going: seems much improved from ALCW14.
m(h1)=m(h2) constraint is very powerful.
1TeV analysis with kinematical fit.
-> significant improvement in mh. -> promising.
PID effect on D meson reconstruction:
Observed impressive effect of PID and correct mass (pi/K) assignment.
Next Step:
- kinematic fit to Zhh -> all hadronic channels.
- vvhh -> vv(bb)(WW) -> vv(bb)(lvjj)
- Combine everything.
8) CP study by recoil mass (Shun Watanuki)
Status:
M_phiZ = M_hZ + eta x M_AZ
h, A: interaction eigen states
phi: mass eigen state
Q: relation btw the formulation used by Ogawa and this one?
Observable: Z production angle.
Preliminary results:
-> eta = 0+/-0.2 for 250fb-1 @ 250GeV
-> +/-0.07 for 1000fb-1.
C: Use more conventional parametrization so that people will
appreciate the results.
9) H+/-W-/+ production (Akimasa Ishikawa)
Status:
Shinzaki-san left.
MC conditions:
f_HWZ=1 and f_HWgamma=0
M_H=150GeV, Ecm=250GeV, (+0.8,-0.3)
Results:
H->tau v
eff.=26.6%, significance=105
H->WZ->lvvv
eff.=8.9%, significance=27.
Limits:
on 2HDM (type X)
-> |F(95%UL)|^2=0.009
-> no meaningful limit
on Georgi-Machacek
-> |F(95%UL)|^2=0.067 : better than LHC
Next Step:
- exclusive analysis
- inclusion of other decay modes such as H->WZ->lvll
9) Discussions: all
See slides by Junping.
1) Higgs analysis
Table of available sigma x BR analyses
Leptonic recoil -> 35MeV -> 22MeV. We should confirm this.
Watanuki -> Jacquline, Ogawa
Hadronic recoil
Tomita (350), new student for 500
h->tau+tau-
Kawada -> Daniel? (CPV)
h->WW*
Ono, Junping, Ogawa
h->gamma gamma, mu mu
Tino
tth
Yuji
self-coupling
Claude, Junping, Kurata
H+H-
Abhinav.
2) BSM
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
3) Systematic uncertainties
W mass: Tsuchimoto
Beam spectrum effect: Jacqulline
Flavor tagging
…
----------------------------------------------------------
The slides shown at the meeting is available from
http://agenda.linearcollider.org/conferenceDisplay.py?confId=6422
see them for details.
---------------------------------------------------------
*) Meeting Schedule:
Next general meeting (2015/06/13 10:30) : Conf.ID: 437
Working group web page:
http://www-jlc.kek.jp/jlc/en/subg/physics