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The 45th General Meeting of ILC Physics Subgroup
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Asia/Tokyo
Description
Date/Time: 10:30~17:30 JST, January 15, 2016
Place: Room 425, Building No.3, KEK
Official Language: English
Video Conference ID: 146 (KEK MCU2)
Vidyo connection: https://vidyoportal.cern.ch/flex.html?roomdirect.html&key=wTH1j1VZJF5LJ3XlWFx2uSjCDVk
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A Summary of The 45th General Meeting of the ILC Physics Subgroup
January 16, 2016 (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)
T.Tanabe (Tokyo)
K.Hidaka (Tokyo gakugei)
K.Ikematsu (Saga)
Remote connection:
K.Tsuchimono (Shinshu)
Y.Sudo (Kyushu)
S.Kawada (Hiroshima)
T.Suehara (Kyushu)
0) Opening comments (K.Fujii)
1.1) Leptonic recoil mass analysis (Jacqueline Yan)
Status:
Improvements since the last meeting:
More understanding of remnant tiny mode-dependence.
Selection finalized.
Expected H20 Precisions:
gZZH: 0.4%
mH: 14%
Investigation of mode dependence
Assign 10% of “unknown mode” to one of the known SM mode and fluctuate
remaining SM modes by the largest of the LHC BR measurements.
-> model independence demonstrated to sub-% level.
Mass measurement with H->bb
No clear advantage.
Next Step:
- Publish the paper in one week.
- Continue with hadronic recoil.
C: The kernel function fit to high stat. toy MC is misleading.
1.2) Higgsino (Jacqueline Yan)
Setup:
delta M ~ 21(15) GeV for neutralinos (chargino)
ILC1: mC1=118GeV, mN2=124GeV, nN1=103GeV
m0=7.03TeV, m1/2=568.3GeV, tanb=1, mu>0, A0=-1.14e4
Status:
Stating with N1N2, looking at distributions of kinematical variables.
Next Step:
- Event selection
C: Photon-photon BG should be more carefully studied.
veto efficiency, pt-cut/acop. cut, effect of crossing angle (phi-dep. cut), etc.
C: Check mono-gluon search at LHC.
3) H->Tau Tau (Shin-ichi Kawada)
Status:
Paper published.
EPJC 75:617 (2015)
Main results:
delta sigxBR/sigxBR
250 3.4% (qqh) 14.4% (eeh) 11.3% (mmh) - (vvh) 3.2% (comb.)
500 4.3% - - 6.9% -
Comb. 2.7% 14.4% 11.3% - 2.6%
Comb. - - - 6.9% 6.9%
-> H20 1.0% for Zh, 3.4% for vvh.
-> delta BR/BR (H20) = 1.4%
Next:
- Jan. 22 phD defence)
- Feb. 5 (ph.D)
Q: How did you combine sigxBRs at different energies?
4) mW Measurements (Koya Tsuchimoto)
Results (masters thesis):
H20 250GeV
Stat. uncertainty: 2.3MeV
Systematics:
JER: 1.4MeV (control sample statistics)
Hadronization: 1.5MeV (GW)
Pileup: 0.5MeV (GW)
Combined: 3.1MeV for H20
5) Top Yukawa coupling study at 500 GeV (Yuji Sudo)
Status:
500GeV (500fb-1), (-/+0.8,+/-0.3)
New from the last meeting
optimized b likeliness thresholds
added loose b tagged category
TMVA BDTG for 8 jets and lep. + 6 jets
Results from cut-based analysis: (significance) for 500fb-1
(-0.8,+0.3) 3.19 (0.87)
(+0.8,-0.3) 2.17 (0.58) -> 3.99 combined
-> |delta gt/gt| = 7.3% for H20 (7.85% before)
MVA results (TMVA BDT):
(-0.8,+0.3) 3.41 (1.07)
(+0.8,-0.3) 2.37 (0.70) -> 4.34 combined
-> |delta gt/gt| = 6.7% for H20
Q: What about 3-b-tag?
A: Probably very difficult because the ttbar BG will increase significantly.
Q: Is the loose b-tag category statistically independent from the tight one?
A: Yes, hence simply combined with the result from the tight one.
Next Step:
- Prepare for publication.
6) Higgs self-coupling (Masakazu Kurata)
Status:
This talk on application of self-organizing mapping to jet clustering.
- start from Durham as input.
- use JADE to calculate distance for SOM.
- then get final jets.
Results:
Slight improvement for Mh.
Next Step:
- Look at wrong energy fraction.
7) Systematic error for lambda_hhh (Junping Tian)
Status:
Updates from the last meeting:
Tim stayed at KEK for 2 weeks in December and studied how we can
constrain the HHVV vertex so as to reduced possible systematic
errors coming from uncertainty in the self-coupling extraction
from the ZZh cross section.
EFT approach:
4 parameters left TGC constraints: cH, cGamma, cHW, C6
cH, cGamma from hWW and hZZ measurements.
cHW from anomalous HVV (Tomohisa’s analysis)
-> We are left with C6 for lambda_hhh.
JT studied how accurately do we need to know the HHVV coupling
using physsim.
Results:
The HHVV diagram gives similar contributions to the Mhh distribution.
delta HHVV / HHVV < 10% needed for 500GeV
delta HHVV / HHVV < 1% needed for 500GeV + 1TeV
Next Step:
- jet clustering.
- reduction of overlay.
8) Discussions:
8-1) Higgsino Study (Jacqueline Yan)
- ILC1 at ECM=500GeV
- New benchmark point with mass close to Ecm/2 and delta m of 10-20GeV.
- Will schedule a dedicated meeting with DESY.
C: Check if the decay is properly handled by Whizard.
C: aa-2f must generate forward going e+e- to test the veto performance.
8-2) Dark Matter (Tomohiko Tanabe)
- Advantage of ILC
leptophilic DM.
compressed spectra.
precision measurements once discovered.
- Mono-photon
BG vvA, vvAA, ..
eeA (Bhabha)
Tasklist
Use newly tuned Pandora
Beam energy spectrum
Make use of new Whizard2 feature about beam spectrum parametrization.
BeamCal reconstruction
EFT analysis
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The slides shown at the meeting is available from
https://agenda.linearcollider.org/event/6979/
see them for details.
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*) Meeting Schedule:
Next general meeting (2016/3/12 10:30) : Conf.ID: 758
Working group web page:
http://www-jlc.kek.jp/jlc/en/subg/physics
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