Searching for
Doubly-Charged Higgs
at the LHC
Sá Borges, Cieza Montalvo
Mauro Tonasse
Nelson Cortez
Universidade do Estado do Rio de Janeiro - Instituto de Física
Universidade Estadual Paulista – Campus de Registro
Universidade Estadual Paulista – Instituto de Física Teórica
Outline
Introduction
Left-Right Model
Experimental Bounds
3-3-1 Model
Pair Production at the LHC
Partial Widths
Results and Conclusion
Left-Right Symmetric Model
SU L (2) x SU R (2) x U BL (1)
 LT, R   e L, R
QLT, R   u d L, R
L
Broken to SM by
R
Scalars
 
 10 1 
2  
    0   L,R  

0
 

 2 2 
 2   L,R
MW2
 2
M Z cos2 W
Invariance
1  2v 2 / k 2
1  4v 2 / k 2
LR
requires
vL  9 GeV k 250 GeV
Interactions
L  hij C 2 j
T
i
(lepton number violation)
left-handed
Bhabha Scattering
Experimental constraints
Couplings
Muonium-antiMuonium
+  e+ e+ e(g-2) 
small off-diagonal couplings
2
h
 2.5x105 M H2
One Doubly Higgs Production
(proton –proton)
WL, R WL, R fusion
Physical single charged scalars
1 , R
2 , L
Proton-Proton
Cross Section
M R  MWR M L  vL
2.4
1.75
Conclusion
W W fusion (H++)
Exceed
Drell-Yan (H++ H--)
Pair Production
 ,Z  

*
Cross section

f f  BB
General

pair

  2  3 s   2 2
2QqA(aL  aR )
A2 (aL2  aR2 )
P Z 
PZZ 
s  
 2Q q P 
2 2
4 4
sW cW
sW cW
 6 

A  T3  sW Q a L  t3  sW q a R  cW q
1
P  2
s
PZZ
1

( s  M Z2 )2  M Z2  2Z
s  2 TeV
Tevatron
5 fb 1
M H   250 GeV
s  14 TeV
LHC
100 fb1
M H   1 TeV
P Z


M Z2
 1 
PZZ 
s


Experimental Bounds
D0
Run II
s =1.96 TeV L=113 pb-1
M H++ > 118.4 GeV M H++ > 98.2 GeV
L
R
CDF Run II
s =1.96 TeV
L= 350 pb-1 M H++ > 113.6 GeV e
L
L= 322 pb-1 M H++ > 112.1 GeV 
L
SU(3)c x SU(3)L x U(1)N
SM chiral extension
Solve family’s replication problem
# Colors 
anomaly cancelation
sin W < 1/4
2
Seesaw mechanism
Charge
Operator


Q 1

3  38  N
e 2
Overview
Left-Handed Leptons
   l PL
Quark Sector
Q1TL   u1 d1 J1  L
Gauge Bosons
 Z W
Scalar Sector
P  (l  L)
T
L

c
T
Q2,3
L   u 2,3 d 2,3 J 2,3  L
Z' V

U

 T   0 1 2   T      0     T        0 
Higgs Potential
V  ...  1     ...  4  †   †    ...  7   †  †   
†
1
f  ijki  j  k
2
2
3 , f  0
Symmetry Breaking
 
 ,  
SU (3)L U (1)N 
 SU (2)L U (1)Y U (1)em
  v    i 
Neutral Sector
Charged Sector
H

(v, u, w)
0
1
H H

1
H
  , 
0
2
H
v2  u2  vW2
  ,

2
H  
0
3
w
u, v
4
2u 4  21v 4
v2  u 2
  ,  , 
u 2  w2
2vw
 fv  29uw 
The Production of a
Pair of Doubly Charged Higgs
at LHC
in the 3-3-1 Model
Drell-Yan Mechanism
Gauge Bosons
Scalars
Gluon-Gluon Fusion
only scalars
Quark loop contribution
from H
0
3
H     
2
2

  J M J  2  J  IJ
2 2 
(32 )  s  J


quark and scalar couplings
s  4M 2

s
for the scalar and the quarks
dx  1  x  sx 
IJ  
ln 1 

2
0 x
MJ 

1
1 2 J 1
I J  ln
2
J 1
2
Exotic Particles Masses
E
M
T
J1
190 1140 2600 1300
J2
J3
Z'
1030 1830 2200
Parameters
1 2 3 4 5 6 7 8 9
-1.2 -1. -1. -2.84 -1.57 1. -3. -1. -1.
v  195 GeV
v  1300 GeV
V
600
U
600
Total Cross Section
Convolute parton momentum spectra
using CTEQ5

1


d
min
 ln 

dy  (  e y )  (  e  y )  ( xs)
ln 
  fq , fq , G
Quarks, gluons
Numerical Integration by VEGAS
Numerical values for

Comparison
Left-Right Model
Comparison
Branching Ratios
M H   1300 GeV
H

H
--
H

qJ l  E  l  M  l  E  l  M 
0.001 0.08
0.005
3.0
6.0
H



1
2.0
U  U Z


19.0 29.0
444
U H V H
0
1

Conclusion
3-3-1
Pair of Doubly Charged Higgs Production at LHC
Large number of doubly
Small branching ratio
charged scalars produced
for ordinary quarks
by Drell-Yan mechanism
and leptons production
Thank you