X. Higgs Bosonen in Supersymmetrie Standard Modell: 1 komplexes Higgs Duplett (4 Komponenten) 1...
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Transcript of X. Higgs Bosonen in Supersymmetrie Standard Modell: 1 komplexes Higgs Duplett (4 Komponenten) 1...
X. Higgs Bosonen in Supersymmetrie
Standard Modell: 1 komplexes Higgs Duplett (4 Komponenten)
1 Vakuumerwartungswert 174 GeV
3 massive Eichbosonen (W+, W-, Z0)Eine mögliche Anregung übrig:
1 neutrales Higgs Boson h
Supersymmetrie2 komplexe Higgs Dupletts (8 Komponenten)3 massive Eichbosonen (W+, W-, Z0)
5 mögliche Anregungen übrig:3 neutrale Higgs Bosonen: h, H, A2 geladene Higgs Bosonen: H+, H-
In niedr. Ordnung 2 Parameter : tan = und mA
In mehr Detail (Martin, 7.1.)
2 komplexe Isospindupletts 8 reelle skalare Felder3 Goldstone Felder (G+, G0, G-) verschwinden in massiven W+, Z0, W-
Verbleiben 3 neutrale (h0, H0, A0) und 2 geladene (H+, H-) Higgs Bosonen
X.1. Higgs Phänomenologie in Supersymmetrie
Minimal Supersymmetry: 3 neutral Higgs Bosons: h, H, A 2 charged Higgs Bosons: H+, H-
at tree level, 2 parameters : tan = v2/v1 and mA
Stephen Martin, hep-ph/97-09356
gMSSM = gSM
MSSM on tree level
t b/ W/Z
h cos/sin -sin/cos sin()
H sin/sin cos/cos cos()
A cot tan -----
MSSM at 2-loop level
Loop level (constrained MSSM):SUSY breaking parameters, assumed to be unified at some scale :
gluino mass and Higgs mass parameter Mğ and
SU(2) gaugino mass term unified at MGUT M2 at MEW
sfermion mass terms : common at MEW Msusy at MEW
sfermion trilinear couplings : common at MEW A at MEW
mixing parameter in the stop sector : Xt = At - cot
Total: 8 parametersmt=171.4 GeV measured
M2, Msusy, Mğ, and Xt chosen to define a “benchmark scenario” tan and mA free to vary
(tan[1, 50] and mA[50, 1000]GeV)
Higgs MassesA ~ degenerate in mass with
h at low massesH and H± high masses
h mass < 130 GeV (all scenarios)
S.Heinemeyer in J.Ellis et al CERN-PH-TH/2007-012
Benchmark scenarios
Examples: Description: http://arxiv.org/abs/hep-ph/0202167
M. Carena, S. Heinemeyer, C.E.M. Wagner, G. Weiglein
Features ofLarge mA and mH:
h is SM-like w/ maximal mass
gMSSM = gSM
H/A/H± produced via Fermion-couplings!Large enhancement of SUSY-Higgs ~(tan)2 possible
Large tan: b- associated production
Small tan: t- associated production
Easy pattern for large mA
t b/ W/Z
h 1 1 -1
H -cot tan 0
A cot tan 0
Example: Widths and Branching Ratios to From Ph.D. thesis, Jana Schaarschmidt, TU Dresden, 2010Widths
H,A:enhanced by tanh:
above m ~ 200 GeVSM-like (narrow)
Branching ratiosSM: negligible above 160 GeVSUSY: always sizableincreasing w/ tanA and H
Cross Sections
Can we see the additional Higgses?
good news:at least one Higgs boson observable for all parameters in all four MSSM benchmark scenarios
bad news: significant area where only lightest Higgs boson h is observablee.g. Higgs discovery, ATLAS prel., 300 fb-1
(M. Schumacher, hep-ph/0410112, ATL-com-phys-2004-070)
X. 2. Search for Neutral Higgs Bosons
How to discover?
Basic 2 2 diagram Corresponding to b-pdf in ProtonDetails much more complex
Add 23, 22, and 21 w/o double counting
Solution: SHERPA MC generator w/ CKKW matchingbetween Matrix Element and Parton Shower contributionsJet fractions agree with analytic calculation (Harlander+Kilgore)
Example: full (down-type) leptonic modesb h/H/A b µ+µ-
b h/H/A b b ℓ+νν ℓ-νν
Main backgrounds (several 100 pb)tt (b)b µ+ν µ-ν tt (b)b ℓ+ν ℓ-ν
qZ ‘‘b‘‘µ+µ- qZ ‘‘b‘‘
Associate A/H production with b-quarks
Mass Resolutions
µ+µ-: exzellente Massenauflösung ~ 3 GeVh/A/H trotzdem nicht getrennt, aber Breite messbar
gröbere Massenauflösung 30 - 40 GeVbenutzt kolineare Näherung des Tau Zerfalls
tan mA=132 GeV
tan mA=150 GeV
M.Warsinsky, DoktorarbeitDresden, 200814 TeV, 30 fb-1
~ 2014 / 2015
J.Schaarschmidt, DiplomarbeitDresden, 2007 14 TeV, 30 fb-1
~ 2014 / 2015
Collinear Approximation
Performance (Ph.D. Thesis, Jana Schaarschmidt, 2010)
Lepton + Hadrons (ATLAS)Typical signal and background distributions at 14 TeV
without b-Jet with b-Jet
Extraction of Z background m shape from data
Use Z and Zee and reweight the lepton signalsJust needs reweighting of track momentaeeNeeds also reweighting of *longitudinal* shower shape
Very successful results
(Jana Schaarschmidt, 2007) Zee (Kathrin Leonhardt, 2008, Patrick Czodrowski, 2009)
Expected sensitivities
X.3. Charged H±
Mass and Couplings:mH±
2 = mA2 + mW
2 in MSSM w/ negligible radiative corrections
No coupling to W, ZTwo fermionic couplings dominant:
Minimum tb coupling at tan √(mt / mb ) ≈ 7
LEP Limits
Direct LEP limits for e+e- H+H- stop at ~mW due to W+W- backgr.
MSSM: BR(H±) dominant for mH± < mt mH± >~ 85 – 89 GeV
LEP direct H± limits:Relevant in non-SUSY 2-Higgs Doublet Models (2HDM)Marginal in MSSM, since mH±
2 = mA2 + mW
2 anyway
Search for Charged Higgs Bosons
New input from b-physics!
Newly developping constraints from b-decays
Gino Isidori, 3rd Workshop: Flavour in the Era of the LHC, 2006
Well defined pattern for exp. observables Starting to give useful constraintsMost limits in literature for 2HDM !No systematic studies for MSSM yet (too many param.!)
Leading-order H± contribution!
2HDM (W.S.Hou, PRD 48 (1993) 2342)
rBBR(2HDM)/BR(SM) =
MSSM (G.Isidori, P.Paradisi, hep-ph/0605012)
Gluino-induced corrections ((mg,mq)to down-type Yukawa couplings considerable for large tan
rBBR(MSSM)/BR(SM) =
B New Physics
222
2
)tan1(
H
B
m
m
2
0
2
2
2
)tan1
tan1(
H
B
m
m
Amplitude M(H±) has opposite sign!suppression
|M (H±)| < |M (W±)|
(near-)cancellation
|M (H±)| ~ |M (W±)|
(near-)compensation
|M (H±)| ~ 2|M (W±)|
enhancement
|M (H±)| > 2|M (W±)|
rB
tan
± ±
~ ~
B Experimental Signature
B First Observations
2.6
C.Bozzi, HCP2007
MSSM interpretation of B- and other constraints
G. Isidori, F. Mescia, P. Paradisi, D. Temes: hep-ph/07030351.01 < Rbs < 1.24 (1 sigma): blue lines
0.8 < R‘B < 0.9 (future guess!): black lines
current 1-sigma would be 0.7 < R‘B < 1.3
NB: 2nd solution for mH < 200GeV not shown!
B → μ+μ− < 8.0 × 10−8: allowed below green linemBs
= 17.35 ± 0.25 ps−1 : allowed below gray line
(g-2)μ: 2 < aμ(exp− SM)/10−9 < 4 : purple lines
Dark Matter (~Bino) density: light blue forbidden
M˜q = 1.5 TeV AU = −1 TeVμ = 1.0 TeVM˜ℓ = 0.4
TeV
M˜q = 1.5 TeV AU = −1 TeVμ = 0.5 TeVM˜ℓ = 0.3
TeV
Two main production processes
for mH± < mt
gg t t bW bH±
for mH± > mt
bg tH± bW H±
Two main decay modesH± dominant for “small“ mH±
below 200 GeV (large tan 10)below 150 GeV (small tan )
H± tb,approaches for “large“ tan BR(tb)/BR() = (mb/m)2 ~ 6
H± at LHC
H±
±
95 130 170 215 310 mH±(GeV)
H±(f
b)
M. Schumacher, ATL-com-phys-2004-070
H±
t
z.B. für mH± > mt : tH± bW
Transversale Massenverteilung nach 30 fb-1
Entdeckungs und Ausschlusspotenzial (Alle Kanäle kombiniert)
H± Discovery reach (ATLAS, TDR 2008)
~