Update on the MSSM Interpretation of ATLAS Higgs Searches
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Update on the MSSM Interpretation of
ATLAS Higgs SearchesMarkus Schumacher , Bonn University
On behalf of the ATLAS Collaboration
Physics at LHC, LHC-Praha 2003, July 2003
• Higgs Sector and 4 Benchmark Scenarios
• Observation potential for: h, A, H, H+-
• Conclusions
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20032
The Higgs Sector of the MSSM
5 physical Higgs bosons: h, H, A, H+, H-
on Born level: 2 parameters tan, mA mass limit mh < MZ
large loop corrections mh < 133 GeV (+-3GeV) corrections depend on 5 SUSY parameters: Xt,M0,M2,Mgluino,
5 parameters fixed in 4 benchmark scenarios considered
scan performed over tan, mA
t b/ W/Z
h cossin -sincos sin()
H sinsin cos/cos cos()
A cot tan -----
high tanlarge BR(h,A,H bb,
smallsmall BR(hbb,
Couplings MSSM/SM
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20033
The Four Benchmark Scenarios
(suggested by M.Carena et al. (hep/ph0202167), same as final LEP paper)
Influence mainly phenomenology of light Higgs boson h
1) MHMAX scenario (MSUSY=1 TeV ) maximal theoretically allowed region for mh
2) Nomixing scenario (now MSUSY= 2 TeV, 1TeV almost excluded by LEP )
small mh difficult for LHC
3) Gluophobic scenario (MSUSY=350GeV)
coupling to gluons suppressed (cancellation of top + stop loops)
small rate for gluon gluon H, Hand Z4 leptons
4) Small scenario (MSUSY = 800 GeV) coupling to b (and ) suppressed (cancellation of sbottom, gluino loops) for large tan and MA 100 to 500 GeV
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20034
Mass of the light Higgs boson h
130GeV<Mh
120<Mh<130GeV
110<Mh<120GeV
100<Mh<110GeV
90<Mh<100GeV
Mh<90GeV
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20035
Some Technicalities
All SM-like cross sections: leading order, no K-factors (K=1)
bottom and top pole masses used for tth, bbh and gbtH+,-
programs: HQQ,HIGLU, … (M.Spira) and xsec for gbtH+,-(T.Plehn)
Higgs masses, alpha_eff.: Feynhiggs 1.3 (S.Heinemeyer et al.)
Branching ratios: HDECAY 3.0 (M.Spira et el.)
(catch up with level of sophistication used at LEP)
decay in SUSY particles switched off for now
discovery = CLB(poisson) < 2.85x10-7 combination with likelihood ratio method (K. Cranmer, F.Cerutti)
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20036
Light CP Even Higgs Boson h
New ! Vector Boson Fusion Channels : qqqqWWqqh
H,ZZ4l ( incl. analysis)
with hWW, (low luminosity only)
g
q
q
q
qh
ggttH
g
hbb,(WW)
Questions: observation after which int. luminosity?
which and how many channels ?
bbh(h)
See M. Vos‘ talk
ggHt
th h h
g
g
g
g
b
b
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20037
Light Higgs boson h: 30 fb -1
bbh
VBF, h
VBF,h+WW
tthbb
WWhlbb
VBF,hWW
VBF channels
cover large part of
MSSM plane
combined
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20038
Light Higgs boson h: 10 fb -1
5 discovery
3observation
5 discovery
3observation
Almost no individual channel observable
need combination of all channels
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 20039
Light Higgs boson h: 300 fb-1
All three
only B
A and B
A and C
For high lumi.: A: h B: tthbb C: hZZ4l contribute
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200310
h: Number of observable final states
1 channel
2 channels
3 channels
4 channels
5 channels
several channels
observable
allows parameter determination ?
300 fb-1
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200311
SM or MSSM ?
Direct search in the following channels:
• Heavy Neutral Higgs bosons: channels for light h + H/A , (lep.+had., had.+had., low lumi only) H/Att, Hhhbb, AZHZhhbbll, WHWWW3l3, HWWll
• Charged Higgs bosons: gbtH+- with H+-tb and one tbl ttbWbH+-blb H+- and t->bqq ttbW bH+-bqq b
(new channels since TDR, channel with extended mass range)
• Marginal differences between 4 benchmark scenarios only MHMAX scenario is shown and discussed
Direct observation of additional Higgs bosons
Discrimination via couplings of light boson h
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200312
Heavy Neutral Bosons: H/A
VBF: H,WW
H/Att
H/Alept.had.
H/A
ttH with Hbb,WW H/A, HZZ4l, WHlbb, Hhhbb, AZHZhhbbll, WHWWW3l3, HWWll
30 fb-1H/Alept.had. +lept.lept. comb.
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200313
Charged Higgs Bosons
gbtH+-
H+tb,tblgbtH+- H+-
, tbqq
ttbWbH+-blb
ttbWbH+-
bqqb
Two mass regions:
i) MH < 170GeV (low lumi)
ii) MH > 180GeV
gbtH+-
top pairs
tH+- bt
tgg
bH
g t
Hb
10 fb-1
30 fb-1300 fb-1
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200314
How many can be seen: h,H,A,H+- ?
MHMAX scenario 300 fb-1
1 boson
2 bosons
3 bosons
All 4 bosons
h only
h,H,A,H+-
h,H,A
No holes !
Complete plane covered
h,H,A
(also in other 3 benchmark scenarios)
Excluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200315
Only h seen: is it the SM or the MSSM ?
only h
> 1 Higgs boson
MHMAX scenario, 300fb-1
BR(h) BR(hWW)R =
From VBF (30 fb-1)
=(RMSSM-RSM)exp
> 2 >1
Only statistical error
2
First preliminary look
532
>1 Higgs bosonExcluded by LEP
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Markus Schumacher, University Bonn Physics at LHC, LHC-Praha 200316
Conclusion
Updated interpretation of Higgs searches in 4 benchmark scenarios have been performed
Good coverage of MA-tan plane for all 4 scen., due to complementarity of search channels
New channels for h,H,A,H+- increase sensitivity
Multiple channels observable for light Higgs h hope for discrimination between SM and MSSM
Thanks for discussion and providing info and programs to
M. Spira (HDECAY,HIGLU,…), S. Heinemeyer (FeynHiggs)
T. Plehn (xsec for gbtH+-), K.Cranmer (statistics code)
especially Elzbieta R.W. +many others from the ATLAS Higgs group