Changes between Version 2 and Version 3 of ZeeBabu


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Timestamp:
Jun 30, 2022, 3:03:50 PM (2 years ago)
Author:
Richard Ruiz
Comment:

Added title and references

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  • ZeeBabu

    v2 v3  
    1 Come back Friday!
     1= {{{SM_ZeeBabu}}}: The Standard Model + Zee-Babu scalars at NLO in QCD =
     2
     3=== Contact Author ===
     4Richard Ruiz
     5* Institute of Nuclear Physics Polish Academy of Science (IFJ PAN)
     6* richard.physics AT gmail.com
     7
     8
     9==== Usage resources ====
     10
     11* [[span(style=color: #FF0000, '''*New*''' )]] For detailed instructions and examples on using the SM_ZeeBabu UFO libraries, see R. Ruiz arXiv:2207.qwerty .
     12* See '''Validation''' section below for additional information
     13
     14==== Citation requests ====
     15
     16* For the Lagrangian, please cite the original papers by Zee [ [#Zee1 1], [#Zee2 2] ] and Babu  [ [#Babu 3] ].
     17* If using any of the UFOs, please cite the companion paper [ [#Ruiz 4] ].
     18
     19== Model Description ==
     20=== Majorana N ===
     21This effective/simplified model extends the Standard Model (SM) field content by introducing three right-handed (RH) neutrinos, which are singlets under the SM gauge symmetry (no color, weak isospin, or weak hypercharge charges). Each RH neutrino possesses one RH Majorana mass. After electroweak symmetry breaking, the Lagrangian with three heavy Majorana neutrinos ''N''i (for i=1,2,3) is given by [ [#Atre 6] ]
     22{{{
     23#!latex
     24\begin{equation}
     25\mathcal{L} = \mathcal{L}_{\rm SM} + \mathcal{L}_{N} + \mathcal{L}_{N~\text{Int.}}
     26\end{equation}
     27}}}
     28The first term is the Standard Model Lagrangian. In the mass basis, i.e., after mixing with active neutrinos, the heavy Majorana neutrinos' kinetic and mass terms are
     29{{{
     30#!latex
     31\begin{equation}
     32\mathcal{L}_{N} = \frac{1}{2}\overline{N_k} i\!\not\!\partial N_k - \frac{1}{2}m_{N_k} \overline{N_k}N_k, \quad k=1,\dots,3,
     33\end{equation}
     34}}}
     35
     36and its interactions with the Weak gauge and Higgs bosons are given by
     37{{{
     38#!latex
     39\begin{eqnarray}
     40\mathcal{L}_{N~\text{Int}} =
     41&-&\frac{g}{\sqrt{2}} W_{\mu}^{+}\sum_{k=1}^{3}\sum_{\ell=e}^{\tau} \overline{N_k}V_{\ell k}^{*}\gamma^{\mu}P_{L}\ell^{-}
     42+{\rm H.c.}
     43\\
     44&-&\frac{g}{2\cos\theta_W}Z_{\mu}\sum_{k=1}^{3}\sum_{\ell=e}^{\tau} \overline{N_k}V_{\ell k}^{*}\gamma^{\mu}P_{L}\nu_\ell
     45+{\rm H.c.}
     46\\
     47&-&\frac{g m_N}{2 M_W}         h \sum_{k=1}^{3}\sum_{\ell=e}^{\tau} \overline{N_k}V_{\ell k}^{*}P_{L}\nu_\ell
     48+{\rm H.c.}
     49\end{eqnarray}
     50}}}
     51Neutrino masses (mNk) and mixing parameters (Vlk) between heavy mass eigenstate and (active) flavor eigenstates are taken to be independent, phenomenological parameters. This allows for maximum flexibility and model independence when calculating rates. Therefore, some care is required by the user.
     52The lepton number- and flavor-violating interactions of the Lagrangian allow for modeling of the Type I, Inverse, and Linear seesaw mechanisms at both lepton, hadron, and lepto-hadron colliders.
     53
     54=== Dirac N ===
     55The Dirac variant of the HeavyN model file contains the same interaction Lagrangian as the Majorana case. The heavy Dirac neutrinos' kinetic and mass terms are [ [#Pascoli2 4] ]
     56{{{
     57#!latex
     58\begin{equation}
     59\mathcal{L}_{N} = \overline{N_k} i\!\not\!\partial N_k - m_{N_k} \overline{N_k}N_k, \quad k=1,\dots,3.
     60\end{equation}
     61}}}
     62
     63=== [[span(style=color: #FF0000, '''*New*''' )]] vSMEFT at dimension six ===
     64In the {{{HeavyN_vSMEFTdim6}}} UFO [ [#Cirigliano 5] ], the {{{HeavyN}}} (Majorana) Lagrangian is extended by the dimension-six EFT operator
     65{{{
     66#!latex
     67\begin{equation}
     68\mathcal{L}_{H\nu e}^{(6)} = \frac{1}{\Lambda^2}   \left(i \tilde{\varphi}^{\dagger} D_{\mu} \varphi\right) \, \bar \nu_R \gamma^\mu \,C_{H\nu l} ~ l_R
     69+  \mathrm{H.c.}\, ,
     70\end{equation}
     71}}}
     72where {{{D_\mu}}} is the usual SM covariant derivative. {{{\Lambda}}} is the EFT cutoff in GeV scale, {{{ C_{H\nu l} }}} is the dimensionless Wilson coefficient, and {{{$l=e,\mu,\tau$}}}. Note that in Ref. [ [#Cirigliano 5] ], {{{ C_{H\nu l} }}} has dimension {{{GeV^-2}}}. In the unitary gauge after and EW symmetry breaking, the leading contribution of this operator can be written in the neutrino mass basis as
     73{{{
     74#!latex
     75\begin{equation}
     76\mathcal{L}_{H\nu e}^{(6)} \approx
     77\frac{g v^2}{2\sqrt{2}\Lambda^2}
     78\sum_{\ell=e}^{\tau}
     79\sum_{k=1}^{3} \,\overline{N_k} 
     80 \left[\bar{C}_{H\nu l}\right]_{k \ell} \gamma^\mu P_R \ell_{R}\,W_\mu^+ 
     81\left(1+\frac{h}{v}\right)^2 +\text{H.c.}
     82\end{equation}
     83}}}
     84Here {{{k=1,\dots,3}}} runs over all three heavy neutrino mass eigenstates and {{{$\ell=e,\mu,\tau$}}} runs over all lepton flavors. For the precise definition of the effective Wilson coefficient {{{$\bar{C}_{H\nu l}$}}}, see Ref. [ [#Cirigliano 5] ].
     85
     86
     87== QCD Corrections ==
     88The above Lagrangian with Goldstone boson couplings and in the Feynman Gauge was implemented into FeynRules  2.3.10. QCD renormalization and R2 rational counter terms were determined using NLOCT 1.02 and FeynArts 3.8. Feynman rules were collected into a single UFO, available below.
     89In the UFO file, five massless quarks are assumed as are zero off-diagonal CKM matrix entries.
     90For additional details, see [ [#Degrande 2] ] and references therein.
     91These additions permit tree-level calculations at LO and NLO in QCD and loop-induced calculations at LO in QCD using MadGraph_aMC@NLO.
     92
     93
     94== Model Files ==
     95'''Note:''' The only difference between NLO and LO libraries is the presence of additional (effective) O(a_s) Feynman rules. By definition the NLO libraries can compute tree-level processes at LO precision.
     96
     97
     98==== Majorana ====
     99 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_NLO_UFO.tgz SM_HeavyN_NLO_UFO.tgz]: Standalone UFO folder. Assumes massless bottom quark and tau lepton, diagonal CKM.
     100
     101 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Gen3Mass_NLO.tgz SM_HeavyN_Gen3Mass_NLO.tgz]: Standalone UFO folder. Assumes massive bottom quark and tau lepton, diagonal CKM.
     102
     103 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_CKM_AllMasses_LO.tgz SM_HeavyN_CKM_AllMasses_LO.tgz]: Standalone UFO folder. Assumes LO in QCD, with CKM elements (in radians), and all particle masses. Majorana equivalent of SM_HeavyN_Dirac_CKM_Masses_LO_UFO.
     104
     105
     106 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/heavyN.fr heavyN.fr]: Main model file. Relies on sm.fr (default FR model file) being declared elsewhere.
     107
     108 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/heavyN_NLO.nb heavyN_NLO.nb]: Mathematica notebook file that generates UFO file from FeynRules model files. Allows user to also run quick sanity checks (optional) on model.
     109
     110 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Files.tgz SM_HeavyN_Files.tgz]: Standalone package containing heavyN.fr, heavyN_NLO.nb, massless.rst (default FR file), diagonalCKM.rst (default FR file), and sm.fr (default FR file).
     111
     112 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_FilesWithUFO.tgz SM_HeavyN_FilesWithUFO.tgz]: Combination of SM_HeavyN_NLO_UFO.tgz and SM_HeavyN_Files.tgz.
     113
     114==== Dirac ====
     115 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Dirac_NLO_UFO.tgz SM_HeavyN_Dirac_NLO_UFO.tgz]: Standalone NLO UFO libraries
     116
     117 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Dirac_NLO_UFO.tgz SM_HeavyN_Dirac_LO_UFO.tgz]: Standalone LO UFO libraries.
     118
     119 * [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Dirac_CKM_Masses_LO_UFO.tgz SM_HeavyN_Dirac_CKM_Masses_LO_UFO.tgz]: Standalone LO UFO libraries, assuming non-diagonal CKM matrix, six quark masses, and three charged lepton masses
     120
     121 * [https://feynrules.irmp.ucl.ac.be/attachment/wiki/HeavyN/heavyN_Dirac.fr heavyN_Dirac.fr]: Main model file. Relies on sm.fr (default FR model file) being declared elsewhere.
     122
     123==== [[span(style=color: #FF0000, '''*New*''' )]] vSMEFT ====
     124* [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_vSMEFTdim6_NLO.tgz SM_HeavyN_vSMEFTdim6_NLO.tgz]: Standalone NLO UFO folder. Assumes massless bottom quark and tau lepton, diagonal CKM.
     125
     126* [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_vSMEFTdim6_XLO.tgz SM_HeavyN_vSMEFTdim6_XLO.tgz]: Standalone LO UFO folder. Assumes massless bottom quark and tau lepton, diagonal CKM.
     127
     128* [https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/heavyN_vSMEFTdim6.fr heavyN_vSMEFTdim6.fr]: Main model file. Relies on sm.fr (default FR model file) being declared elsewhere.
     129
     130== Download and Unpack ==
     131 * To download any of the packages and unpack via the terminal, use the commands:
     132
     133==== Majorana NLO ====
     134~/Path $ wget http://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_NLO_UFO.tgz
     135
     136~/Path $ tar -zxvf SM_HeavyN_NLO_UFO.tgz
     137
     138==== Majorana LO ====
     139~/Path $ wget http://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_FilesWithUFO.tgz
     140
     141~/Path $ tar -zxvf SM_HeavyN_FilesWithUFO.tgz
     142
     143==== Dirac NLO ====
     144~/Path $ wget http://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Dirac_NLO_UFO.tgz
     145
     146~/Path $ tar -zxvf SM_HeavyN_Dirac_NLO_UFO.tgz
     147
     148==== Dirac LO ====
     149~/Path $ wget http://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_Dirac_LO_UFO.tgz
     150
     151~/Path $ tar -zxvf SM_HeavyN_Dirac_LO_UFO.tgz
     152
     153==== vSMEFT NLO ====
     154~/Path $ wget https://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_vSMEFTdim6_NLO.tgz
     155
     156~/Path $ tar -zxvf SM_HeavyN_vSMEFTdim6_NLO.tgz
     157
     158==== vSMEFT LO ====
     159~/Path $ wget http://feynrules.irmp.ucl.ac.be/raw-attachment/wiki/HeavyN/SM_HeavyN_vSMEFTdim6_XLO.tgz
     160
     161~/Path $ tar -zxvf SM_HeavyN_vSMEFTdim6_XLO.tgz
     162
     163
     164
     165== Notes ==
     166 * For instructions on using the HeavyN UFO, see C. Degrande, et al, arXiv:1602.06957 and S. Pascoli, et al, arXiv:1812.08750
     167
     168 * The flagship {{{HeavyN}}} UFO model contains 15 free parameters:
     169  * Three masses: mN1, mN2, mN3. Defaults are 300 GeV, 500 GeV, and 1 TeV, respectively.
     170  * Three widths: WN1, WN2, WN3. Defaults are 0.303 GeV, 1.50 GeV, and 12.3 GeV, respectively.
     171  * Nine real (no CP violation) mixing parameters: V''lk'' for ''l'' = ''e, mu, tau'' and ''k'' = 1,2,3. Default values are V''lk'' = Identity(3x3), i.e., {{{Ve1 = Vmu2 = Vta3 = 1}}} and all others zero.
     172  * '''Note''': VlN are restricted to be real in the model file.
     173  * '''Note''': Default parameters are set so "out-of-the-box" checks can be made with [ [#Alva 1] ] and [ [#Degrande 2] ].
     174
     175* For the Majorana file, particle identification (PID) codes for N1,...,N3, follow standard HEP MCPID codes: 9900012, 9900014, 9900016
     176
     177* For the Dirac file, to avoid conflict with Pythia8, where the above PIDs are reserved for Majorana fields, the nonstandard HEP MCPID codes for N1,...,N3 are:9990012, 9990014, 9990016
     178
     179* For the vSMEFT file, 10 additional model parameters are introduced:
     180  * One EFT cutoff scale {{{Lambda}}} in units of GeV.
     181  * Nine Wilson coefficients coupling {{{N_k}}} to {{{l}}}: {{{CeN1, CeN2, CeN3, CmuN1, CmuN2, CmuN3, CtaN1, CtaN2, CtaN3}}}
     182  * '''Note''': Default parameters are set such that {{{Lambda=1000}}} (GeV), {{{CeN1=CmuN2=CtaN3=1}}}, and all other coefficients are zero
     183
     184
     185== Validation ==
     186* The model file was validated at LO in  [ [#Alva 1] ]; see Tables 2 and 5 for further validation checks.
     187* The model file was validated at NLO in [ [#Degrande 2] ]; see Table 1 for further validation checks.
     188* For very large masses, this model has been constructed to satisfy the Goldstone Equivalence Theorem:
     189{{{
     190#!latex
     191\begin{eqnarray}
     192\text{BR}(N_i \rightarrow W^+ \ell^-) &=& \text{BR}(N_i \rightarrow W^- \ell^+) =
     193\\
     194\text{BR}(N_i \rightarrow Z \nu_\ell + Z \overline{\nu_\ell} ) &=&
     195\text{BR}(N_i \rightarrow h \nu_\ell + h \overline{\nu_\ell} ) = 25\%.
     196\end{eqnarray}
     197}}}
     198* Helicity dependence of LNV and LNC decay rates of Majorana neutrino decays was validated in [ [#Ruiz 7] ]
     199
     200== Studies that have used the above model files ==
     201Please email to update this space.
     202* Golling, et al., ''Physics at a 100 TeV pp collider: beyond the Standard Model phenomena'', arXiv:1606.00947
     203* CMS, ''Search for heavy neutral leptons in events with three charged leptons in proton-proton collisions at 13 TeV'', arXiv:1802.02965 [hep-ex]
     204* CMS, ''Search for heavy Majorana neutrinos in same-sign dilepton channels in proton-proton collisions at 13 TeV'', arXiv:1806.10905 [hep-ex]
     205
     206== References ==
     207* For studies of Majorana neutrinos, please consider citing [ 6 ] for the Lagrangian and [ 1-2 ] for the Majorana FR/UFO files.
     208* For studies of heavy Dirac neutrinos, please also consider citing [ 4 ].
     209* For studies of heavy neutrinos in vSMEFT, please consider citing [ 5 ].
     210
     211
     212[ [#Zee1 1], [#Zee2 2] ] and Babu  [ [#Babu 3] ].
     213* If using any of the UFOs, please cite the companion paper [ [#Ruiz 4] ]
     214
     215[=#Zee1] [1] A. Zee, ''Charged Scalar Field and Quantum Number Violations,'' Phys. Lett. '''B161''' (1985) 141, https://inspirehep.net/literature/214241
     216
     217[=#Zee2] [2] A. Zee, ''Charged Scalar Field and Quantum Number Violations,'' Nucl. Phys. '''B264''' (1986) 99,
     218https://inspirehep.net/literature/218115
     219
     220[=#Babu] [3] K. Babu, ``Model of 'Calculable' Majorana Neutrino Masses,''    Phys. Lett. '''B203''' (1988) 132,
     221https://inspirehep.net/literature/22952
     222
     223[=#Ruiz] [4] R. Ruiz, ``Doubly Charged Higgs Boson Production at Hadron Colliders II: A Zee-Babu Case Study,''
     224arXiv:2207.qwerty [hep-ph]
     225