PHYS08200604017 Manimala Mitra - Homi Bhabha National Institute

More documents

Recommendations

Info

We can also see that for Σ − m 1 decay, the decay rate into e − m is about 5 orders of magnitude larger than into µ − m/τm. − The trend is opposite for Σ − m 2 decay, where the decay is predominantly into µ − m /τ− m . Both of these features can be understood from Eq. (3.56) and the values of the Yukawa couplings taken (cf. Table 3.1). Σ − m 1 decay into e − m and µ − m/τm − is proportional to a 2 4 and a 2 11, respectively. The ratio of the decay widths seen in the figure matches the ratio a 2 4 /(a2 11 ) ∼ 105 . Similarly, one can check that for Σ − m 2 decay, the corresponding ratio is 4a 2 11/(a 6 +a 8 ) 2 , which agrees with the middle panel of Fig. 3.5. Finally, the fact that the decay rate of Σ − m 3 → µ − m h0 is less than that of Σ − m 2 → µ − m h0 can also be understood in terms of Eq. (3.56) and the Yukawa coupling values taken for the calculation. We next turn to the decay width for Σ ± m i → l ± m j H 0 . Expression for the decay rate is same as that given by Eq. (3.52) except that now M h 0 is replaced by the H 0 mass M H 0. For this decay channel the A ji factor is dominantly given by C H0 ,R l ± Σ ± ≃ 1 √ 2 S † 11Y † Σ T 22sinα. (3.57) Note that compared to the effective vertex factor for Σ ± m i → l ± m j h 0 given in Eq. (3.55), the effective vertex factor given above for Σ ± m i → l ± m j H 0 is suppressed by sinα. Since sinα ∼ 10 −6 , the decay rate of Σ ± m i into H 0 are heavily suppressed. We show in Fig. 3.6 this decay rate calculated from exact numerical results. Comparing Fig. 3.5 with Fig. 3.6, we see that decays into H 0 are suppressed by a factor of about ∼ 10 11 , as expected from the order of magnitude estimate. Therefore, we can neglect Σ ± m i → l ± m j H 0 for all practical purposes. From Table 3.13 it is easy to see that the decay rate Σ ± m i → l ± m j A 0 will be almost identical to that that predicted for Σ ± m i → l ± m j h 0 . The dominant vertex factors for the two process are the same and hence the only difference could come from the difference between the Higgs masses. However, it is easy to see from Eq. (3.52) that the effect of the Higgs mass on the decay rate is not very significant, especially for relatively heavy fermions. Σ 0 m → l∓ m H± The decay rate for this channel is also given by Eq. (3.52), and is governed primarily by the vertex factor C H± ,R l ± Σ ≃ √ 1 S 11Y † † 0 Σ 2 U∗ 22cosβ. (3.58) As discussed in detail in the Appendix, the factor cosβ ∼ 1. The matrix U 22 displays features similar to the matrix T 22 . Therefore, the form of dominant vertex factor for this caseissimilar tothatgiveninEq. (3.56). Thecorrespondingdecay ratesareshowninFig. 54
Σ 0 -> e m 1 m H + Σ 0 -> e m 2 m H + Σ 0 -> µ m 1 m / τ m H + Σ 0 m 2 -> µ m /τ m H + Σ 0 m 3 -> µ m /τ m H + 10 0 10 0 10 -2 10 -2 10 -2 Γ(GeV) 10 -4 10 -4 10 -4 10 -6 10 -6 10 -6 10 -8 200 400 600 800 1000 1200 M Σ1 (GeV) 10 0 400 600 800 1000 1200 10 -8 400 600 800 1000 1200 M Σ2 (GeV) 10 -8 M Σ3 (GeV) Figure 3.7: Variation of Γ(Σ 0 m i → l mj H + ) with M Σi 3.7. All features seen for Σ − m i → l mj h 0 is also seen here. Decay channel Σ 0 m 3 → e ∓ m j H ± is forbidden. Decayratestoµ ∓ m isequal todecay ratetoτ ∓ m. Thehugehierarchy inthedecay rates of Σ 0 m 1 and Σ 0 m 2 into e m and µ m /τ m are also present due to same reason as given for Σ − m → l− m h0 decays. The decay rate and flavor structure for the final state charged leptons is therefore seen to be same here as for the decay of charged heavy fermions into charged light leptons and h 0 . However, in this case we have a charged Higgs in the final state and it should be easy to tag this and differentiate the two processes in the detector at LHC. Σ 0 m → ν mh 0 /H 0 /A 0 We next turn to the decay channels with a light neutrino in the final state. This will give missing energy in the final state. Decay of the neutral Σ 0 m will create a neutrino and a neutral Higgs. As in the case of decay of Σ ± m to charged leptons and neutral Higgs, one can check from Table 3.14 that the decay to the Higgs H 0 is heavily suppressed due to 55
Page 1:
Neutrinos and Some Aspects of Physi
Page 5:
Declaration This thesis is a presen
Page 9 and 10:
Acknowledgments First and foremost,
Page 11:
iii
Page 14 and 15:
trino masses are bounded within 0.1
Page 16 and 17:
softly broken Z 2 symmetry, the mas
Page 18 and 19:
tribimaximal mixing in the neutrino
Page 20 and 21:
Bibliography [1] Two Higgs doublet
Page 23 and 24:
Contents 1 Introduction 1 1.1 Stand
Page 25:
6.2.2 Charged Lepton Masses and Mix
Page 29 and 30:
Chapter 1 Introduction 1.1 Standard
Page 31 and 32: For positive µ 2 and λ, the Higgs
Page 33 and 34: type of Yukawa interaction between
Page 35 and 36: interaction with the Higgs as λ f
Page 37 and 38: where ˆΦ is the MSSM chiral super
Page 39: (2004); A. Ghosal, hep-ph/0304090;
Page 44 and 45: active flavor. In recent years, sev
Page 46 and 47: Figure 2.1: The possible neutrino s
Page 48 and 49: Majorana mass term breaks lepton nu
Page 50 and 51: The kinetic term of the Higgs tripl
Page 52 and 53: ight handed neutrino N R can be exa
Page 54 and 55: alternating group which is not a di
Page 56 and 57: The group contains two one-dimensio
Page 58 and 59: from neutral-current interactions i
Page 60: [31] K. S. Babu and R. N. Mohapatra
Page 64 and 65: of producing the heavy fermion trip
Page 66 and 67: where Σ ± Ri = Σ1 Ri ∓iΣ2 Ri
Page 68 and 69: while U ν diagonalizes m ν and ˜
Page 70 and 71: It is evident that the masses of th
Page 72 and 73: 0.001 0.001 0.0001 0.0001 U e3 1e-0
Page 74 and 75: if we neglect terms proportional to
Page 76 and 77: calculations for lepton flavor viol
Page 78 and 79: fb. Therefore, it is obvious that t
Page 80 and 81: Σ − -> e m 1 m h 0 Σ − -> e m
Page 84 and 85: the sinα term. However, decay to h
Page 86 and 87: Σ − m 1 ->ν m1 W Σ 0 m 1 ->ν
Page 88 and 89: Γ 2HDM (Σ 0 m → ν m H 0 ) ≃
Page 90 and 91: Decay modes Σ ± m 1 Σ ± m 2 Σ
Page 92 and 93: III seesaw model. Clearly, for our
Page 94 and 95: Sl no Channels Effective cross-sect
Page 96 and 97: • The other dominant decay channe
Page 102 and 103: 3.9 Conclusions The seesaw mechanis
Page 104 and 105: Appendix A: The Scalar Potential an
Page 106 and 107: B: The Interaction Lagrangian B.1:
Page 108 and 109: C H0 ,L 1√ ll 2 (T 11Y † l S 11
Page 110 and 111: c Z,L ll c Z,L lΣ − c Z,L Σ −
Page 112 and 113: Bibliography [1] S. Weinberg, Phys.
Page 114: Lett. B 615, 231 (2005); Phys. Rev.
Page 118 and 119: violating λ ′′ coupling are co
Page 120 and 121: neutralino-neutrinomassmatrixandins
Page 122 and 123: 4.3 Symmetry Breaking In this secti
Page 124 and 125: +(M 2 +m 2 Σ )ũ2 + ∑ m 2˜ν i
Page 126 and 127: Here M 1,2 are the soft supersymmet
Page 128 and 129: is violated, we have neutrino-neutr
Page 130 and 131: (M 1,2 ,M,µ,Y Σi ,v 1,2 ,ũ,u i )
Page 132 and 133:
In our model in addition to the sta
Page 134 and 135:
4.8 Conclusion In this work we have
Page 136 and 137:
Y Σi √2 ĤuˆΣ 0 0c Rˆν L i
Page 138 and 139:
while the parameter α 1 is α 1 =
Page 140 and 141:
Bibliography [1] S. Roy and B. Mukh
Page 142 and 143:
[15] M. C. Gonzalez-Garcia and J. W
Page 144 and 145:
ν i A Σi • ˜ν i h,H,A × χ
Page 146 and 147:
118
Page 148 and 149:
of the form ⎛ ⎞ A B B m ν =
Page 150 and 151:
triplet representation of A 4 , l =
Page 152 and 153:
m 0 =0.016 m 0 =0.024 m 0 =0.032 2
Page 154 and 155:
Higgs Neutrino mass matrix Eigenval
Page 156 and 157:
5.3. The deviation of the mixing an
Page 158 and 159:
Sin 2 θ 12 Sin 2 θ 13 Sin 2 θ 23
Page 160 and 161:
Figure 5.5: Scatter plot showing th
Page 162 and 163:
Figure 5.6: Same as Fig. 5.5 but fo
Page 164 and 165:
mass matrix is then given as ⎛ m
Page 166 and 167:
Bibliography [1] M. C. Gonzalez-Gar
Page 168 and 169:
140
Page 170 and 171:
142
Page 172 and 173:
a way that the residual µ−τ sym
Page 174 and 175:
where Λ is the cut-off scale of th
Page 176 and 177:
m 2 . The eigenvectors are given as
Page 178 and 179:
For λ ≃ 2 × 10 −2 ≃ λ2 c 2
Page 180 and 181:
2 2 2 1 1 1 y 2 0 y 3 0 y 4 0 -1 -1
Page 182 and 183:
0.08 0.25 0.06 0.2 10 -3 m νee (eV
Page 184 and 185:
We show the values of |U e3 | ≡ s
Page 186 and 187:
while the branching ratio for this
Page 188 and 189:
6.4 The Vacuum Expectation Values I
Page 190 and 191:
where we have defined B = (b+f 1 +f
Page 192 and 193:
VEV alignments. Another way the VEV
Page 194 and 195:
(2006); M. Maltoni, T. Schwetz, M.
Page 196 and 197:
168
Page 198 and 199:
metric standard model in chapter 1.
Page 200 and 201:
mally two. However the R-parity vio
Page 202 and 203:
sector contains the exact/approxima
show all

PHYS08200604017 Manimala Mitra - Homi Bhabha National Institute

Create successful ePaper yourself

Delete template?

Save as template?