Transcript ppt - Rencontres de Moriond

Andreas Crivellin
Overview of Flavor Physics
with focus on the Minimal Supersymmetric Standard Model
and two-Higgs-doublet models
Supported by a Marie Curie Intra-European Fellowship of the European Community's 7th
Framework Programme under contract number (PIEF-GA-2012-326948).
Outline:


Introduction
Flavor observables
 
 B  
q
Meson mixing
 Radiative B decays
 Lepton flavor violation
 Tauonic B decays



Flavor Phenomenology of 2HDMs
Conclusions
2
Flavor-Physics vs LHC

Direct searches
probe the scale of NP Λ
Limited by available energy

Flavor physics
probes NP indirectly through loop effects
Limited by the size of flavor violation δ
and the available statistics/precision
3
Flavor-Physics vs LHC
4
2HDM of type II
Hd
(MSSM at tree-level)


One Higgs doublet couples
only to down-quarks
(and charged leptons),
the other Higgs doublet
couples only to up-quarks.
di
Y
di
df
Hu
ui
2 additional free parameters:
tan(β)=vu/vd and the heavy Higgs
mass (MSSM like Higgs potential)
Y
ui
uf
mqi  vqY
qi
mH  mA0  mH   mH 0

All flavor-violations is due to the CKM matrix:
neutral Higgs-quark couplings are flavor-conserving.
5
2HDM of type III

Both Higgs doublets couple simultaneously to
up and down quarks.
Hd
Hu
di

d
fi
df
m  v Y v 
d
ij


d
d ij
d
u ij
u ,d
ij
u i  ufi u f
m  v Y  vd 
u
ij
u
u ij
u
ij
The parameters 
describe flavor-changing
neutral Higgs interactions
u ,d
In the MSSM,  ij are induced via loops
6
Bs   



New SM predictions

Effect of
s included
De Bruyn et al. 1204.1737

tan   50
mH  700 GeV
mH  500 GeV
mH  300 GeV
New lattice result for f B
s
HPQCD, FLAG

NLO electroweak corrections
Bobeth et al. 1311.1348

NNLO QCD corrections
Hermann et al. 1311.1347
Br  Bs   LHCbCMS   2.9  0.7  109
Br  Bs   SM
  3.65  0.23 109

Stringent constraints on scalar
operators (e.g. Higgs induced
flavor-violation)

Starting to probe vector
operators
7
Constraints on NP models from
 
 
Bs    and Bd   
Plot from David Straub’s talk
8
B  X q
b  s

NNLO QCD corrections
Br b  s exp   3.43  0.21  0.07  104
Br b  s SM   3.13  0.22  104
tan   50
mH  700 GeV
mH  500 GeV
mH  300 GeV
Preliminary, M. Misiak, talk in Portoroz

Best constraints on the charged
Higgs mass m  380 GeV
H
Hermann et al 1208.2788
b  d

Hadronic uncertainties largely
drop out in the CP averaged BR
b
Benzke et al. 1003.5012, Hurth et al. 1005.1224
Br b  d  exp  1.41  0.57  105
5
Br b  d  SM  1.540.26
0.31 10
AC, L. Mercolli 1106.5499
9
Meson mixing
For an review see e.g. Lenz, Nierste et al. arXiv:1008.1593



Kaon mixing
 Very sensitive to NP with
d
additional phases generic
NP > 10000 TeV
W
Most stringent constraints
on extra dimensions
s
Bs, Bd mixing
 Now in good agreement with the SM
D mixing
d
 Poor SM prediction for
g
the mass difference
due to non-perturbative effects
s
 No sign for additional phases
SM
s
t , c, u
W
t , c, u
d
MSSM
s
d
g
d
d
10
Squark mass splitting in the MSSM:
Constraints from Kaon and D mixing


Cancellations between
different contributions
Non-degenerate
squark masses
are allowed
Interesting for LHC
benchmark scenarios.
Maximally allowed
mass-splitting
Alignment to Yd
Constraints from D mixing
Alignment to Yu
Constraints from Kaon mixing
Minimally allowed
mass-splitting
AC, M. Davidkov 1002:2653
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Lepton Flavour Violation

In the SM with massive neutrinos
EXTREMELY small O(10-50)
Observation of LFV would establish
physics beyond the SM


23  0, 32  0
32  0, 23  0
  e best constraints on generic NP
32  0, 23  0
  e conversion
Predicted ratio in the 2HDM
excellent experimental prospects
sensitive to Higgs mediated flavour-violation
new predictions for the scalar-nucleon couplings
AC, M. Procura, M. Hoferichter 1312.4951
    ,   e ,   eee,   eee
Sensitive to flavour-changing Z effects
12
Tauonic B decays

Tree-level decays in the SM via W-boson

Sensitive to a charged Higgs due to the
heavy tau lepton in the final state.
Observable
SM
Br  B   
 0.719
Experiment
0.115
0.076
 10 1.15  0.23 104
4
Br  B  D  Br  B  D   0.297  0.017
Br  B  D*  Br  B  D*  
0.252  0.003
b
c, u
W


Significance
1.6 
0.440  0.072
2.0 
0.332  0.030
2.7 
All three observables are above the SM prediction
13
Type-II 2HDM

Allowed
2σ regions from:
(superimposed)
b  s
B  
K   /   
B  D
Bs  
B  D*
LHC
Tension from B  D*
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B→τν in the 2HDM III

Constructive contribution to B→τν using  31 is possible
while satisfying
the constraints
from FCNC
processes.
u
Allowed
regions from:
B   1
B   2
dn
15
B→D(*)τν in the 2HDM III

B→D(*)τν and B→Dτν can be explained simultaneously
u
using  32 without violating bounds from FCNC
processes.
Allowed
regions from:
B  D
B  D*
Check
model via
H 0 , A0  tc
t h c
0
16
Conclusions

Flavor-Physics puts stringent limits on NP

Nearly all measurements agree very well with the
SM expectations

Tauonic B decays might be a hint for NP???

A charged Higgs boson in a 2HDM with flavourviolation in the up sector might explain this
0
0
A
,
H
 tc
Search for
t  h0c
17
Lepton flavour
violating B decays
Allowed regions respecting
the constraints from   e and
tan   30
tan   40
tan   50
Bs  
18
Loop corrections to Higgs-quark
couplings in the MSSM

Before
After
electroweak
electroweak
symmetry
symmetry
breaking
breaking
Hd
Hu
Ad
Y d
di
df

d LR
fi A
 v 
Hd
d f ddi
Hd
d f di
di
df

d LR
fi Y
 v 
Hu
d f dui
Hu
d f di
One-to-one correspondence between Higgs-quark couplings
and chirality changing self-energies. (In the decoupling limit)
19
NLO calculation of the quark
self-energies
Example
diagrams
NLO calculation is important for:

Computation of effective Higgsquark vertices.

Determination of the Yukawa
couplings of the MSSM
superpotential.
Reduction of the matching scale
dependence
DR
on  shell
20