Transcript A light non-standard Higgs: to be or not to be @ a (Super) B factory* Miguel-Angel Sanchis-Lozano email: [email protected] Department of Theoretical Physics &

A light non-standard Higgs: to be or not to be
@ a (Super) B factory*
Miguel-Angel Sanchis-Lozano
email: [email protected]
Department of Theoretical Physics & IFIC
University of Valencia – CSIC
Spain
*Based on arXiv:0709.3747
hep-ph/0702190, hep-ph/0610046
hep-ph/020156, hep-ph/0307313
Special thanks to J.Duboscq (CLEO)
for many iIluminating discussions
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October 20, 2007
Miguel A. Sanchis-Lozano
IFIC-Valencia
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Light neutral Higgs scenarios






H
H
u
d
Hˆ u   0  , Hˆ d   0  , Sˆ
 Hu 
 Hd 
Higgs sector in the NMSSM: (seven)
2 neutral CP-odd Higgs bosons (A1,2)
3 neutral CP-even Higgs bosons (H1,2,3 )
2 charged Higgs bosons (H±)
L & H
Light and heavy Higgs
bosons can live together
PQ symmetry or U(1)R slightly broken → a light pseudoscalar Higgs A1  A0
A1  cos A AMSSM  sin  A As
Coupling of A1 to down type fermions
tan β = v2 / v1
 cos A tan 
Light dark matter?
The A1 would be the lightest Higgs:
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NMSSM candidate compatible with present bounds:
Light neutralino with a singlet component
McElrath [hep-ph/0506151]
Miguel A. Sanchis-Lozano
IFIC-Valencia
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Light Higgs windows at LEP (CPV MSSM)
hep-ex/0406057
hep-ex/0406057
Diagram illustrating the effective coupling of a Higgs
mass eigenstate H1 to the Z. Only the CP-even admixture
h and H couple to Z while the CP-odd A does not: hence
the coupling of the H1 is reduced wrt a CPC scenario.
hep-ex/0406057
CPX MSSM 95% exclusion areas using scans with different values
of arg (At,b). The region excluded by Yukawa searches, Z-width
constraints or decay independent searches is shown in red
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CPX MSSM 95% exclusion areas using scans with different
values of the top mass
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Next-to-Minimal Supersymmetric Model (NMSSM)
Much less constrained by LEP data
and B-physics observables than the MSSM
Higgs mass values allowed down to several GeV
Hiller, hep-ph/0404220
Similarly for Little Higgs models with an extended
structure of global U(1) symmetries broken both
spontaneously and explicitly, possibly leading to
light pseudoscalar particles in the Higgs spectrum
Kraml et al. hep-ph/0608079
Upsilon decays should be useful in the search for a light Higgs
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 Leptonic decays
Formalism
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Mixing of a pseudoscalar Higgs A0 and a b resonance
e+ e-     τ+ τsin 2   m2
 mA20  imA0 A0 m 2 

M2   2
 m m 2  im  
b 0
b 0 b 0 

A0  cos A00  sin  bo
A00 , b0
unmixed states
A0 , b
mixed (physical)
states
b  cos b 0  sin  A00
g A0  cos g A0  sin  gbo0
0
0
gb  cos gb 0  sin  g A0
0
A0  | cos |2 A0  | sin  |2 bo
0
b  | cos |2 b 0  | sin  |2 A0
1/ 2
 3m3b 

m  
 4v 2 


2
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0
| Rb (0) |  X d
Xd = cosA tanβ
Miguel A. Sanchis-Lozano
IFIC-Valencia
Smaller coupling
strength than in
the MSSM
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b / A0 mixing
Xd = cosA tanβ
Xd = 10,20,40
Xd = 10
Possible spectroscopic consequences
broader b ?
b mass shift ?
due to the new physics
contribution
b > [b2g]
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Hyperfine splitting m-mb
unexpectedly large/or small
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Our proposal:
Test of lepton universality in  leptonic decays
R /  
 ( nS ) 
( em)

QCD+binding energy effects
small for the pseudoscalar A0
B  B B

1
B
B
Wilczek formula
Mixing effect
• Non-resonant decay
R / l
2
m2 X d2  mA0

1 2
2 
8 v 
m
• Resonant decay
B(  sb ) 
M1 b

Mixing effect
1 4 I 2 Qb k 3


3mb2
2

2
0
 

|
cos

|

[
A


 ]
 

| cos |2 A0  | sin  |2 b 0

0
R / l
B[   b ]
| sin  |2 [ A0     ]


B[  l  l  ]
| sin  |2 A0  | cos  |2 b 0
0
M1 transition probability
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Lepton universality in the SM
BF(  ee )  BF(      )  BF(    )  ee    
Neglecting phase space and helicity flip effects. Higher-order SM effects are negligible
Γll is an inclusive quantity:   l+ l- is accompanied by an infinite number of soft photons
The test of lepton universality can be seen as complementary to searches for
monochromatic photons in the  γ ττ channel (see B. Heltsley talk)
To order α3:
Γll = Γll 0 [1+δvac+δvertex ]  Γll 0 [1+δvac]
3α /4π ~ 0.17%
7.6%
δ vac=δee+δ+δ+ δquarks
Warning!
Contribution potentially dangerous for testing
lepton universality if final-state radiation is
not properly taken into account in the MC
to obtain the detection efficiency in the
analysis of experimental data
Albert et al. Nucl. Phys. B 166 (1980) 460
Divergencies/singularities free at any order: Bloch and Nordsieck theorem &
Kinoshita-Sirlin-Lee-Nauenberg theorem
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IFIC-Valencia
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Testing Lepton Universality
BF(  ee )  BF(      )  BF(     )
ee    
Channel: *
BF[e+e-]
(1S)
2.38 ± 0.11 %
(1S)
(2S)
2.60 ± 0.10 %
0.09 ± 0.06
2.48 ± 0.05 % 2.60 ± 0.10 %
0.05 ± 0.04
2.00 ± 0.21 %
0.05 ± 0.14
1.93 ± 0.17 % 2.00 ± 0.21 %
0.04 ± 0.14
2.29 ± 0.30 %
0.05 ± 0.16
2.18 ± 0.21 % 2.29 ± 0.30 %
0.05 ± 0.16
2.18 ± 0.20 %
(3S)
*
R/l
1.91 ± 0.16 %
(2S)
(3S)
BF[+-]
BF[μ+ μ-]
From PDG ‘07
Lepton Universality in
Upsilon decays implies
<R/l > = 0
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R /  
Miguel A. Sanchis-Lozano
IFIC-Valencia
 ( nS ) s
( em)

B  B B

1
B
B
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LU
Lepton Universality Breaking?
R/e(1S)
( em)  4 2Qb2
R/(1S)
Rn (0)
M
2

2
 (1  2 x )(1  4 x )1/ 2



(smoothly) decreasing function of x
wit h x  m2 / M 2
R/e(2S)
 ( nS ) / K ( x ) B / K ( x )
Rˆ /  

1
( em) / K ( xl )
B / K ( xl )
R/(2S)
R/e(3S)
R/(3S)
-0.1
0.0
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0.1
0.2
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IFIC-Valencia
0.3
0.4
R/l
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Expected LU breaking
Green line: non-resonant decay
Black line: resonant decay
Red line: sum
Xd=10, b0 = 5 MeV
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IFIC-Valencia
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A closer look at the
NMSSM parameter space
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IFIC-Valencia
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Xd =10
Xd > 5``
Xd
κ
λ
λ
Aλ = -200 GeV
μ = 150 GeV
Aκ = -15 GeV
tanβ= 50
Aλ ~ - Κ μ / λ
Κ - (4/3) λ =0
cos A  
0.1 ≤| cos A |≤ 0.5
tanβ ~ 1/ [Aλ+Κ (μ / λ) ]
m A1
2
 v( A  2 s ) sin 2
2 s ( A  s )  3 A s sin 2
 3 A cos2  A

 3s 
 2 A sin 2  A 
 3 sin 2 

Ananthanarayan & Pandita, hep-ph/9601372
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IFIC-Valencia
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In several NMSSM parameter regions, it may happen at the same time:
Large tanβ (for Aλ + κ s ≈ 0)
0.1 ≤ | cos A | ≤ 0.5 (A0 mainly singlet but not completely)
|Xd| = 5 – 25 for tanβ = 50
Low mass (e.g. 10 GeV) of the lightest CP-odd Higgs boson A0
Low fine-tunning in order to get a Higgs-like boson explaining the
Z+b-jets event excess at LEP (Dermisek & Gunion, hep-ph/0510322)
Suggestive coincidence !
“There should be one thousand reasons for not running a B factory at (3S)
but right now I cannot think of one”
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IFIC-Valencia
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Summary
What if...
there exists a light Higgs-like particle about 10 GeV?
A high luminosity B factory would be the ideal place to
discover/study it, e.g. looking at
- decay into τ+ τ- (): Lepton universality test (M.A.S.L., arXiv:0709.3747)
- direct searches for monochromatic photons (see B. Heltsley talk)
Dermisek, Gunion and McElrath, hep-ph/0612031
( also Mangano and Nason in  γ μμ decays, arXiv:0704:1719 )
Complementary/Implications to LHC/ILC searches!
+ related topics: muon g-2 anomaly, light dark matter
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IFIC-Valencia
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Back up
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Proposal of testing lepton universality (to the percent level) @ a (Super) B factory
With the machine sitting on the (3S)
(3S)  π + π - (1S,2S) → + BF  2-4 x 10-2
BF  2 x 10-2
(3S)  π + π - (1S,2S) →  +  BF  10-1  +  - → l + l X, l = e, 
(3S)  +  -
Final state & BF
hep-ph/0610046
π + π - + BF  4 - 8 x 10-4
π+π- l+ l-
Compare
rates
BF  5 - 10 x 10-5
+  -
BF  2 x 10-2
BF  2 x 10-2
(3S)   +  → l + l - X, l = e, 
l+ l-X
Compare
rates
BF  2 x 10-3
Statistical error ≈ 0.07 / √ # fb-1
With the machine sitting on the (4S)
(4S)  π + π - (1S,2S) → + BF  10-4
BF  2 x 10-2
(4S)  π + π - (1S,2S) →  +  BF  10-1  +  - → l + l - X, l = e, 
QWG5 DESY
October 20, 2007
Miguel A. Sanchis-Lozano
IFIC-Valencia
Systematic error ≤ 0.037
π + π - + BF  2 x 10-6
π + π -l + l - X
Compare
rates
BF  2 x 10-7
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Searches for b states over more than 20 years
No signal found so far!
Entangled both theoretically and experimentally?
Mixing
b resonance
/
A0 Higgs boson
Enfant terrible
Petit bourgeois
Spectroscopic consequences: quite larger or smaller hyperfine splitting
An unlikely but not impossible situation:
(ns) and b(nS) mass levels might be reversed!
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October 20, 2007
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IFIC-Valencia
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