The 45th General Meeting of ILC Physics Subgroup

→ Asia/Tokyo
Keisuke Fujii (IPNS, KEK)
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



----------------------------------------------------------
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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