Load
FeynCalc and the necessary add-ons or other packages
This example uses a custom QED model created with FeynRules. Please
evaluate the file FeynCalc/Examples/FeynRules/QED/GenerateModelYukawa.m
before running it for the first time.
description = "Renormalization, Yukawa, MS and MSbar, 1-loop" ;
If [ $FrontEnd === Null ,
$FeynCalcStartupMessages = False ;
Print [ description] ;
] ;
If [ $Notebooks === False ,
$FeynCalcStartupMessages = False
] ;
$LoadAddOns = { "FeynArts" } ;
<< FeynCalc`
$FAVerbose = 0 ;
FCCheckVersion[ 10 , 0 , 0 ] ;
FeynCalc 10.0.0 (dev version, 2024-08-07 16:59:34 +02:00, 2f62a22c). For help, use the online documentation , ‾ visit the forum ‾ and have a look at the supplied examples . ‾ The PDF-version of the manual can be downloaded here . ‾ \text{FeynCalc }\;\text{10.0.0 (dev
version, 2024-08-07 16:59:34 +02:00, 2f62a22c). For help, use the
}\underline{\text{online} \;\text{documentation},}\;\text{ visit the
}\underline{\text{forum}}\;\text{ and have a look at the supplied
}\underline{\text{examples}.}\;\text{ The PDF-version of the manual can
be downloaded }\underline{\text{here}.} FeynCalc 10.0.0 (dev version, 2024-08-07 16:59:34 +02:00, 2f62a22c). For help, use the online documentation , visit the forum and have a look at the supplied examples . The PDF-version of the manual can be downloaded here .
If you use FeynCalc in your research, please evaluate FeynCalcHowToCite[] to learn how to cite this software. \text{If you use FeynCalc in your
research, please evaluate FeynCalcHowToCite[] to learn how to cite this
software.} If you use FeynCalc in your research, please evaluate FeynCalcHowToCite[] to learn how to cite this software.
Please keep in mind that the proper academic attribution of our work is crucial to ensure the future development of this package! \text{Please keep in mind that the proper
academic attribution of our work is crucial to ensure the future
development of this package!} Please keep in mind that the proper academic attribution of our work is crucial to ensure the future development of this package!
FeynArts 3.11 (3 Aug 2020) patched for use with FeynCalc, for documentation see the manual ‾ or visit www . feynarts . de . ‾ \text{FeynArts }\;\text{3.11 (3 Aug 2020)
patched for use with FeynCalc, for documentation see the
}\underline{\text{manual}}\;\text{ or visit
}\underline{\text{www}.\text{feynarts}.\text{de}.} FeynArts 3.11 (3 Aug 2020) patched for use with FeynCalc, for documentation see the manual or visit www . feynarts . de .
If you use FeynArts in your research, please cite \text{If you use FeynArts in your
research, please cite} If you use FeynArts in your research, please cite
∙ T. Hahn, Comput. Phys. Commun., 140, 418-431, 2001, arXiv:hep-ph/0012260 \text{ $\bullet $ T. Hahn, Comput. Phys.
Commun., 140, 418-431, 2001, arXiv:hep-ph/0012260} ∙ T. Hahn, Comput. Phys. Commun., 140, 418-431, 2001, arXiv:hep-ph/0012260
We keep scaleless B0 functions, since otherwise the UV part would not
come out right.
$KeepLogDivergentScalelessIntegrals = True ;
FAPatch[ PatchModelsOnly -> True ] ;
(*Patched 4 FeynArts models.*)
Generate Feynman diagrams
params = { InsertionLevel -> { Particles}, Model -> FileNameJoin [{ "LY" , "LY" }],
GenericModel -> FileNameJoin [{ "LY" , "LY" }], ExcludeParticles -> {}} ;
top [ i_ , j_ ] := CreateTopologies[ 1 , i -> j ,
ExcludeTopologies -> { Tadpoles, WFCorrections, WFCorrectionCTs}] ;
topCT[ i_ , j_ ] := CreateCTTopologies[ 1 , i -> j ,
ExcludeTopologies -> { Tadpoles, WFCorrections, WFCorrectionCTs}] ;
{ diagFermionSE, diagFermionSECT} = InsertFields[ #, { F [ 10 ]} -> { F [ 10 ]},
Sequence @@ params] & / @ { top [ 1 , 1 ], topCT[ 1 , 1 ]} ;
{ diagScalarSE, diagScalarSECT} = InsertFields[ #, { S [ 1 ]} -> { S [ 1 ]},
Sequence @@ params] & / @ { top [ 1 , 1 ], topCT[ 1 , 1 ]} ;
{ diagVertexFFS, diagVertexFFSCT} = InsertFields[ #, { F [ 10 ], S [ 1 ]} -> { F [ 10 ]},
Sequence @@ params] & / @ { top [ 2 , 1 ], topCT[ 2 , 1 ]} ;
{ diagVertexSSSS, diagVertexSSSSCT} = InsertFields[ #, { S [ 1 ], S [ 1 ]} -> { S [ 1 ], S [ 1 ]},
Sequence @@ params] & / @ { top [ 2 , 2 ], topCT[ 2 , 2 ]} ;
diag1[ 0 ] = diagFermionSE[[ 0 ]][ diagFermionSE[[ 1 ]], diagFermionSECT[[ 1 ]]] ;
diag2[ 0 ] = diagScalarSE[[ 0 ]][ diagScalarSE[[ 1 ]], diagScalarSECT[[ 1 ]]] ;
diag3[ 0 ] = diagVertexFFS[[ 0 ]][ diagVertexFFS[[ 1 ]], diagVertexFFSCT[[ 1 ]]] ;
diag4[ 0 ] = diagVertexSSSS[[ 0 ]][ diagVertexSSSS[[ 1 ]], diagVertexSSSSCT[[ 1 ]]] ;
Paint[ diag1[ 0 ], ColumnsXRows -> { 2 , 1 }, SheetHeader -> None ,
Numbering -> Simple, ImageSize -> 256 { 2 , 1 }] ;
Paint[ diag2[ 0 ], ColumnsXRows -> { 2 , 1 }, SheetHeader -> None ,
Numbering -> Simple, ImageSize -> 256 { 2 , 1 }] ;
Paint[ diag3[ 0 ], ColumnsXRows -> { 2 , 1 }, SheetHeader -> None ,
Numbering -> Simple, ImageSize -> 256 { 2 , 1 }] ;
Paint[ diag4[ 0 ], ColumnsXRows -> { 3 , 1 }, SheetHeader -> None ,
Numbering -> Simple, ImageSize -> 256 { 3 , 1 }] ;
Obtain the amplitudes
The 1/(2Pi)^D prefactor is implicit.
Fermion self-energy including the counter-term
amp1[ 0 ] = FCFAConvert[ CreateFeynAmp[ diag1[ 0 ], Truncated -> True ,
GaugeRules -> {}, PreFactor -> 1 ],
IncomingMomenta -> { p }, OutgoingMomenta -> { p },
LoopMomenta -> { l }, UndoChiralSplittings -> True ,
ChangeDimension -> D , List -> False , SMP -> True ,
FinalSubstitutions -> {}, Contract -> True ]
− ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) ( l 2 − Mx 2 ) . ( ( l − p ) 2 − Mphi 2 ξ S ( 1 ) ) − i Mx ( Zmx Zx − 1 ) + i ( Zx − 1 ) γ ⋅ p -\frac{(-i g).(\gamma \cdot
l+\text{Mx}).(-i
g)}{\left(l^2-\text{Mx}^2\right).\left((l-p)^2-\text{Mphi}^2 \xi
_{S(1)}\right)}-i \;\text{Mx} (\text{Zmx} \;\text{Zx}-1)+i (\text{Zx}-1)
\gamma \cdot p − ( l 2 − Mx 2 ) . ( ( l − p ) 2 − Mphi 2 ξ S ( 1 ) ) ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) − i Mx ( Zmx Zx − 1 ) + i ( Zx − 1 ) γ ⋅ p
Scalar self-energy including the counter-term
amp2[ 0 ] = FCFAConvert[ CreateFeynAmp[ diag2[ 0 ], Truncated -> True ,
GaugeRules -> {}, PreFactor -> 1 ],
IncomingMomenta -> { p }, OutgoingMomenta -> { p },
LoopMomenta -> { l }, UndoChiralSplittings -> True ,
ChangeDimension -> D , List -> False , SMP -> True , Contract -> True ]
la 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) − i Mphi 2 ( Zmphi Zphi − 1 ) + i p 2 ( Zphi − 1 ) \frac{\text{la}}{2 \left(l^2-\text{Mphi}^2
\xi _{S(1)}\right)}-i \;\text{Mphi}^2 (\text{Zmphi} \;\text{Zphi}-1)+i
p^2 (\text{Zphi}-1) 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) la − i Mphi 2 ( Zmphi Zphi − 1 ) + i p 2 ( Zphi − 1 )
Fermion-scalar vertex including the counter-term
amp3[ 0 ] = FCFAConvert[ CreateFeynAmp[ diag3[ 0 ], Truncated -> True ,
GaugeRules -> {}, PreFactor -> 1 ],
IncomingMomenta -> { p1, k }, OutgoingMomenta -> { p2},
LoopMomenta -> { l }, UndoChiralSplittings -> True , ChangeDimension -> D ,
List -> False , SMP -> True , Contract -> True ]
− i ( − i g ) . ( γ ⋅ ( k + l ) + Mx ) . ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) ( l 2 − Mx 2 ) . ( ( k + l ) 2 − Mx 2 ) . ( ( k + l − p2 ) 2 − Mphi 2 ξ S ( 1 ) ) − i g ( Zg Zphi Zx − 1 ) -\frac{i (-i g).(\gamma \cdot
(k+l)+\text{Mx}).(-i g).(\gamma \cdot l+\text{Mx}).(-i
g)}{\left(l^2-\text{Mx}^2\right).\left((k+l)^2-\text{Mx}^2\right).\left((k+l-\text{p2})^2-\text{Mphi}^2
\xi _{S(1)}\right)}-i g \left(\text{Zg} \sqrt{\text{Zphi}}
\;\text{Zx}-1\right) − ( l 2 − Mx 2 ) . ( ( k + l ) 2 − Mx 2 ) . ( ( k + l − p2 ) 2 − Mphi 2 ξ S ( 1 ) ) i ( − i g ) . ( γ ⋅ ( k + l ) + Mx ) . ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) − i g ( Zg Zphi Zx − 1 )
Scalar self-interaction vertex including the counter-term
amp4[ 0 ] = FCFAConvert[ CreateFeynAmp[ diag4[ 0 ], Truncated -> True ,
GaugeRules -> {}, PreFactor -> 1 ],
IncomingMomenta -> { p1, p2}, OutgoingMomenta -> { p3, p4},
LoopMomenta -> { l }, UndoChiralSplittings -> True , ChangeDimension -> D ,
List -> False , SMP -> True , Contract -> True ]
− 2 tr ( ( Mx − γ ⋅ l ) . ( − i g ) . ( γ ⋅ ( − l − p2 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p4 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p3 + p4 ) + Mx ) . ( − i g ) ) ( l 2 − Mx 2 ) . ( ( l + p2 ) 2 − Mx 2 ) . ( ( l + p2 − p4 ) 2 − Mx 2 ) . ( ( l + p2 − p3 − p4 ) 2 − Mx 2 ) − i la ( Zla Zphi 2 − 1 ) -\frac{2 \;\text{tr}((\text{Mx}-\gamma
\cdot l).(-i g).(\gamma \cdot (-l-\text{p2})+\text{Mx}).(-i g).(\gamma
\cdot (-l-\text{p2}+\text{p4})+\text{Mx}).(-i g).(\gamma \cdot
(-l-\text{p2}+\text{p3}+\text{p4})+\text{Mx}).(-i
g))}{\left(l^2-\text{Mx}^2\right).\left((l+\text{p2})^2-\text{Mx}^2\right).\left((l+\text{p2}-\text{p4})^2-\text{Mx}^2\right).\left((l+\text{p2}-\text{p3}-\text{p4})^2-\text{Mx}^2\right)}-i
\;\text{la} \left(\text{Zla} \;\text{Zphi}^2-1\right) − ( l 2 − Mx 2 ) . ( ( l + p2 ) 2 − Mx 2 ) . ( ( l + p2 − p4 ) 2 − Mx 2 ) . ( ( l + p2 − p3 − p4 ) 2 − Mx 2 ) 2 tr (( Mx − γ ⋅ l ) . ( − i g ) . ( γ ⋅ ( − l − p2 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p4 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p3 + p4 ) + Mx ) . ( − i g )) − i la ( Zla Zphi 2 − 1 )
Calculate the amplitudes
Fermion self-energy
amp1[ 1 ] = amp1[ 0 ] // ReplaceAll [ #, { Zx -> 1 + alpha dZx,
Zmx -> 1 + alpha dZmx}] & // Series [ #, { alpha, 0 , 1 }] & //
Normal // ReplaceAll [ #, alpha -> 1 ] &
− ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) ( l 2 − Mx 2 ) . ( ( l − p ) 2 − Mphi 2 ξ S ( 1 ) ) − i Mx ( dZmx + dZx ) + i dZx γ ⋅ p -\frac{(-i g).(\gamma \cdot
l+\text{Mx}).(-i
g)}{\left(l^2-\text{Mx}^2\right).\left((l-p)^2-\text{Mphi}^2 \xi
_{S(1)}\right)}-i \;\text{Mx} (\text{dZmx}+\text{dZx})+i \;\text{dZx}
\gamma \cdot p − ( l 2 − Mx 2 ) . ( ( l − p ) 2 − Mphi 2 ξ S ( 1 ) ) ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) − i Mx ( dZmx + dZx ) + i dZx γ ⋅ p
Tensor reduction allows us to express the electron self-energy in
tems of the Passarino-Veltman coefficient functions.
amp1[ 2 ] = TID[ amp1[ 1 ], l , ToPaVe -> True ]
i π 2 g 2 ( γ ⋅ p ( Mphi 2 ( − ξ S ( 1 ) ) + Mx 2 + p 2 ) + 2 Mx p 2 ) B 0 ( p 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) 2 p 2 + i π 2 g 2 γ ⋅ p A 0 ( Mphi 2 ξ S ( 1 ) ) 2 p 2 − i π 2 g 2 A 0 ( Mx 2 ) γ ⋅ p 2 p 2 − i ( dZmx Mx + dZx Mx − dZx γ ⋅ p ) \frac{i \pi ^2 g^2 \left(\gamma \cdot p
\left(\text{Mphi}^2 \left(-\xi _{S(1)}\right)+\text{Mx}^2+p^2\right)+2
\;\text{Mx} p^2\right) \;\text{B}_0\left(p^2,\text{Mx}^2,\text{Mphi}^2
\xi _{S(1)}\right)}{2 p^2}+\frac{i \pi ^2 g^2 \gamma \cdot p
\;\text{A}_0\left(\text{Mphi}^2 \xi _{S(1)}\right)}{2 p^2}-\frac{i \pi
^2 g^2 \;\text{A}_0\left(\text{Mx}^2\right) \gamma \cdot p}{2 p^2}-i
(\text{dZmx} \;\text{Mx}+\text{dZx} \;\text{Mx}-\text{dZx} \gamma \cdot
p) 2 p 2 i π 2 g 2 ( γ ⋅ p ( Mphi 2 ( − ξ S ( 1 ) ) + Mx 2 + p 2 ) + 2 Mx p 2 ) B 0 ( p 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) + 2 p 2 i π 2 g 2 γ ⋅ p A 0 ( Mphi 2 ξ S ( 1 ) ) − 2 p 2 i π 2 g 2 A 0 ( Mx 2 ) γ ⋅ p − i ( dZmx Mx + dZx Mx − dZx γ ⋅ p )
Discard all the finite pieces of the 1-loop amplitude
amp1Div[ 0 ] = PaVeUVPart[ amp1[ 2 ], Prefactor -> 1 / (2 Pi )^ D ] //
FCReplaceD[ #, D -> 4 - 2 Epsilon] & // Series [ #, { Epsilon, 0 , 0 }] & // Normal //
FCHideEpsilon // SelectNotFree2[ #, { SMP[ "Delta" ], dZx,
dZmx}] & // Simplify // Collect2[ #, DiracGamma] &
i ( 32 π 2 dZx + Δ g 2 ) γ ⋅ p 32 π 2 − i Mx ( 16 π 2 dZmx + 16 π 2 dZx − Δ g 2 ) 16 π 2 \frac{i \left(32 \pi ^2
\;\text{dZx}+\Delta g^2\right) \gamma \cdot p}{32 \pi ^2}-\frac{i
\;\text{Mx} \left(16 \pi ^2 \;\text{dZmx}+16 \pi ^2
\;\text{dZx}-\Delta g^2\right)}{16 \pi ^2} 32 π 2 i ( 32 π 2 dZx + Δ g 2 ) γ ⋅ p − 16 π 2 i Mx ( 16 π 2 dZmx + 16 π 2 dZx − Δ g 2 )
Equating the result to zero and solving for dZx and dZmx we obtain
the renormalization constants in the minimal subtraction schemes.
solMSbar1 = FCMatchSolve[ amp1Div[ 0 ], { g , la, Mx, DiracGamma, SMP}] ;
solMS1 = solMSbar1 /. SMP[ "Delta" ] -> 1 / Epsilon
FCMatchSolve: Solving for: { dZmx , dZx } \text{FCMatchSolve: Solving for:
}\{\text{dZmx},\text{dZx}\} FCMatchSolve: Solving for: { dZmx , dZx }
FCMatchSolve: A solution exists. \text{FCMatchSolve: A solution
exists.} FCMatchSolve: A solution exists.
{ dZmx → 3 g 2 32 π 2 ε , dZx → − g 2 32 π 2 ε } \left\{\text{dZmx}\to \frac{3 g^2}{32 \pi
^2 \varepsilon },\text{dZx}\to -\frac{g^2}{32 \pi ^2 \varepsilon
}\right\} { dZmx → 32 π 2 ε 3 g 2 , dZx → − 32 π 2 ε g 2 }
Scalar self-energy
la 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) − i Mphi 2 ( Zmphi Zphi − 1 ) + i p 2 ( Zphi − 1 ) \frac{\text{la}}{2 \left(l^2-\text{Mphi}^2
\xi _{S(1)}\right)}-i \;\text{Mphi}^2 (\text{Zmphi} \;\text{Zphi}-1)+i
p^2 (\text{Zphi}-1) 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) la − i Mphi 2 ( Zmphi Zphi − 1 ) + i p 2 ( Zphi − 1 )
amp2[ 1 ] = amp2[ 0 ] // ReplaceRepeated [ #, { Zphi -> 1 + alpha dZphi,
Zmphi -> 1 + alpha dZmphi}] & // Series [ #, { alpha, 0 , 1 }] & //
Normal // ReplaceAll [ #, alpha -> 1 ] &
la 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) − i Mphi 2 ( dZmphi + dZphi ) + i dZphi p 2 \frac{\text{la}}{2 \left(l^2-\text{Mphi}^2
\xi _{S(1)}\right)}-i \;\text{Mphi}^2 (\text{dZmphi}+\text{dZphi})+i
\;\text{dZphi} p^2 2 ( l 2 − Mphi 2 ξ S ( 1 ) ) la − i Mphi 2 ( dZmphi + dZphi ) + i dZphi p 2
Tensor reduction allows us to express the scalar self-energy in tems
of the Passarino-Veltman coefficient functions.
amp2[ 2 ] = TID[ amp2[ 1 ], l , ToPaVe -> True ]
1 2 i π 2 la A 0 ( Mphi 2 ξ S ( 1 ) ) − i ( dZmphi Mphi 2 + dZphi Mphi 2 − dZphi p 2 ) \frac{1}{2} i \pi ^2 \;\text{la}
\;\text{A}_0\left(\text{Mphi}^2 \xi _{S(1)}\right)-i \left(\text{dZmphi}
\;\text{Mphi}^2+\text{dZphi} \;\text{Mphi}^2-\text{dZphi}
p^2\right) 2 1 i π 2 la A 0 ( Mphi 2 ξ S ( 1 ) ) − i ( dZmphi Mphi 2 + dZphi Mphi 2 − dZphi p 2 )
Discard all the finite pieces of the 1-loop amplitude
amp2Div[ 0 ] = PaVeUVPart[ amp2[ 2 ], Prefactor -> 1 / (2 Pi )^ D ] //
FCReplaceD[ #, D -> 4 - 2 Epsilon] & // Series [ #, { Epsilon, 0 , 0 }] & // Normal //
FCHideEpsilon // SelectNotFree2[ #, { SMP[ "Delta" ], dZphi, dZmphi}] & // Simplify //
Collect2[ #, p , Mphi] &
i dZphi p 2 − i Mphi 2 ( 32 π 2 dZmphi + 32 π 2 dZphi − Δ la ξ S ( 1 ) ) 32 π 2 i \;\text{dZphi} p^2-\frac{i
\;\text{Mphi}^2 \left(32 \pi ^2 \;\text{dZmphi}+32 \pi ^2
\;\text{dZphi}-\Delta \;\text{la} \xi _{S(1)}\right)}{32 \pi
^2} i dZphi p 2 − 32 π 2 i Mphi 2 ( 32 π 2 dZmphi + 32 π 2 dZphi − Δ la ξ S ( 1 ) )
Equating this to zero and solving for dZphi and dZmphi obtain the
renormalization constants in the minimal subtraction schemes.
solMSbar2 = FCMatchSolve[ amp2Div[ 0 ], { g , la, Mphi, p , SMP, GaugeXi}]
solMS2 = solMSbar2 /. SMP[ "Delta" ] -> 1 / Epsilon;
FCMatchSolve: Following coefficients trivially vanish: { dZphi → 0 } \text{FCMatchSolve: Following coefficients
trivially vanish: }\{\text{dZphi}\to 0\} FCMatchSolve: Following coefficients trivially vanish: { dZphi → 0 }
FCMatchSolve: Solving for: { dZmphi } \text{FCMatchSolve: Solving for:
}\{\text{dZmphi}\} FCMatchSolve: Solving for: { dZmphi }
FCMatchSolve: A solution exists. \text{FCMatchSolve: A solution
exists.} FCMatchSolve: A solution exists.
{ dZphi → 0 , dZmphi → Δ la ξ S ( 1 ) 32 π 2 } \left\{\text{dZphi}\to 0,\text{dZmphi}\to
\frac{\Delta \;\text{la} \xi _{S(1)}}{32 \pi ^2}\right\} { dZphi → 0 , dZmphi → 32 π 2 Δ la ξ S ( 1 ) }
Fermion-scalar vertex
amp3[ 1 ] = amp3[ 0 ] // ReplaceRepeated [ #, { Zphi -> 1 + alpha dZphi,
Zx -> 1 + alpha dZx, Zg -> 1 + alpha dZg}] & //
Series [ #, { alpha, 0 , 1 }] & // Normal // ReplaceAll [ #, alpha -> 1 ] &
− i ( − i g ) . ( γ ⋅ ( k + l ) + Mx ) . ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) ( l 2 − Mx 2 ) . ( ( k + l ) 2 − Mx 2 ) . ( ( k + l − p2 ) 2 − Mphi 2 ξ S ( 1 ) ) − i g ( dZg + dZphi 2 + dZx ) -\frac{i (-i g).(\gamma \cdot
(k+l)+\text{Mx}).(-i g).(\gamma \cdot l+\text{Mx}).(-i
g)}{\left(l^2-\text{Mx}^2\right).\left((k+l)^2-\text{Mx}^2\right).\left((k+l-\text{p2})^2-\text{Mphi}^2
\xi _{S(1)}\right)}-i g
\left(\text{dZg}+\frac{\text{dZphi}}{2}+\text{dZx}\right) − ( l 2 − Mx 2 ) . ( ( k + l ) 2 − Mx 2 ) . ( ( k + l − p2 ) 2 − Mphi 2 ξ S ( 1 ) ) i ( − i g ) . ( γ ⋅ ( k + l ) + Mx ) . ( − i g ) . ( γ ⋅ l + Mx ) . ( − i g ) − i g ( dZg + 2 dZphi + dZx )
The result of the tensor reduction is quite large, since we keep the
full gauge dependence and do not specify the kinematics
amp3[ 2 ] = TID[ amp3[ 1 ], l , ToPaVe -> True , UsePaVeBasis -> True ]
i π 2 g 3 B 0 ( p2 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) + i π 2 g 3 ( − ( γ ⋅ k ) . ( γ ⋅ k ) − Mx γ ⋅ k + 2 Mx 2 ) C 0 ( k 2 , p2 2 , k 2 − 2 ( k ⋅ p2 ) + p2 2 , Mx 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) − i π 2 g 3 ( ( γ ⋅ k ) . ( γ ⋅ k ) + 2 Mx γ ⋅ k ) C 1 ( k 2 , − 2 ( k ⋅ p2 ) + k 2 + p2 2 , p2 2 , Mx 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) − i π 2 g 3 ( ( γ ⋅ k ) . ( γ ⋅ p2 ) + 2 Mx γ ⋅ p2 ) C 1 ( p2 2 , − 2 ( k ⋅ p2 ) + k 2 + p2 2 , k 2 , Mx 2 , Mphi 2 ξ S ( 1 ) , Mx 2 ) − 1 2 i g ( 2 dZg + dZphi + 2 dZx ) i \pi ^2 g^3
\;\text{B}_0\left(\text{p2}^2,\text{Mx}^2,\text{Mphi}^2 \xi
_{S(1)}\right)+i \pi ^2 g^3 \left(-(\gamma \cdot k).(\gamma \cdot
k)-\text{Mx} \gamma \cdot k+2 \;\text{Mx}^2\right)
\;\text{C}_0\left(k^2,\text{p2}^2,k^2-2 (k\cdot
\;\text{p2})+\text{p2}^2,\text{Mx}^2,\text{Mx}^2,\text{Mphi}^2 \xi
_{S(1)}\right)-i \pi ^2 g^3 ((\gamma \cdot k).(\gamma \cdot k)+2
\;\text{Mx} \gamma \cdot k) \;\text{C}_1\left(k^2,-2 (k\cdot
\;\text{p2})+k^2+\text{p2}^2,\text{p2}^2,\text{Mx}^2,\text{Mx}^2,\text{Mphi}^2
\xi _{S(1)}\right)-i \pi ^2 g^3 ((\gamma \cdot k).(\gamma \cdot
\;\text{p2})+2 \;\text{Mx} \gamma \cdot \;\text{p2})
\;\text{C}_1\left(\text{p2}^2,-2 (k\cdot
\;\text{p2})+k^2+\text{p2}^2,k^2,\text{Mx}^2,\text{Mphi}^2 \xi
_{S(1)},\text{Mx}^2\right)-\frac{1}{2} i g (2
\;\text{dZg}+\text{dZphi}+2 \;\text{dZx}) i π 2 g 3 B 0 ( p2 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) + i π 2 g 3 ( − ( γ ⋅ k ) . ( γ ⋅ k ) − Mx γ ⋅ k + 2 Mx 2 ) C 0 ( k 2 , p2 2 , k 2 − 2 ( k ⋅ p2 ) + p2 2 , Mx 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) − i π 2 g 3 (( γ ⋅ k ) . ( γ ⋅ k ) + 2 Mx γ ⋅ k ) C 1 ( k 2 , − 2 ( k ⋅ p2 ) + k 2 + p2 2 , p2 2 , Mx 2 , Mx 2 , Mphi 2 ξ S ( 1 ) ) − i π 2 g 3 (( γ ⋅ k ) . ( γ ⋅ p2 ) + 2 Mx γ ⋅ p2 ) C 1 ( p2 2 , − 2 ( k ⋅ p2 ) + k 2 + p2 2 , k 2 , Mx 2 , Mphi 2 ξ S ( 1 ) , Mx 2 ) − 2 1 i g ( 2 dZg + dZphi + 2 dZx )
Discard all the finite pieces of the 1-loop amplitude
amp3Div[ 0 ] = PaVeUVPart[ amp3[ 2 ], Prefactor -> 1 / (2 Pi )^ D ] // DiracSimplify //
FCReplaceD[ #, D -> 4 - 2 Epsilon] & // Series [ #, { Epsilon, 0 , 0 }] & // Normal //
FCHideEpsilon // SelectNotFree2[ #, { SMP[ "Delta" ], dZphi,
dZx, dZg}] & // ReplaceAll [ #, Join [ solMSbar1, solMSbar2]] & // Simplify // FCFactorOut[ #, g ] &
g ( 3 i Δ g 2 32 π 2 − i dZg ) g \left(\frac{3 i \Delta g^2}{32 \pi
^2}-i \;\text{dZg}\right) g ( 32 π 2 3 i Δ g 2 − i dZg )
Equating this to zero and solving for dZg we obtain the
renormalization constant in the minimal subtraction schemes.
solMSbar3 = FCMatchSolve[ amp3Div[ 0 ], { g , SMP}]
solMS3 = solMSbar3 /. SMP[ "Delta" ] -> 1 / Epsilon;
FCMatchSolve: Solving for: { dZg } \text{FCMatchSolve: Solving for:
}\{\text{dZg}\} FCMatchSolve: Solving for: { dZg }
FCMatchSolve: A solution exists. \text{FCMatchSolve: A solution
exists.} FCMatchSolve: A solution exists.
{ dZg → 3 Δ g 2 32 π 2 } \left\{\text{dZg}\to \frac{3
\Delta g^2}{32 \pi ^2}\right\} { dZg → 32 π 2 3Δ g 2 }
Scalar self-interaction
vertex
amp4[ 1 ] = amp4[ 0 ] // ReplaceRepeated [ #, { Zphi -> 1 + alpha dZphi,
Zla -> 1 + alpha dZla}] & //
Series [ #, { alpha, 0 , 1 }] & // Normal // ReplaceAll [ #, alpha -> 1 ] &
− 2 tr ( ( Mx − γ ⋅ l ) . ( − i g ) . ( γ ⋅ ( − l − p2 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p4 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p3 + p4 ) + Mx ) . ( − i g ) ) ( l 2 − Mx 2 ) . ( ( l + p2 ) 2 − Mx 2 ) . ( ( l + p2 − p4 ) 2 − Mx 2 ) . ( ( l + p2 − p3 − p4 ) 2 − Mx 2 ) − i la ( dZla + 2 dZphi ) -\frac{2 \;\text{tr}((\text{Mx}-\gamma
\cdot l).(-i g).(\gamma \cdot (-l-\text{p2})+\text{Mx}).(-i g).(\gamma
\cdot (-l-\text{p2}+\text{p4})+\text{Mx}).(-i g).(\gamma \cdot
(-l-\text{p2}+\text{p3}+\text{p4})+\text{Mx}).(-i
g))}{\left(l^2-\text{Mx}^2\right).\left((l+\text{p2})^2-\text{Mx}^2\right).\left((l+\text{p2}-\text{p4})^2-\text{Mx}^2\right).\left((l+\text{p2}-\text{p3}-\text{p4})^2-\text{Mx}^2\right)}-i
\;\text{la} (\text{dZla}+2 \;\text{dZphi}) − ( l 2 − Mx 2 ) . ( ( l + p2 ) 2 − Mx 2 ) . ( ( l + p2 − p4 ) 2 − Mx 2 ) . ( ( l + p2 − p3 − p4 ) 2 − Mx 2 ) 2 tr (( Mx − γ ⋅ l ) . ( − i g ) . ( γ ⋅ ( − l − p2 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p4 ) + Mx ) . ( − i g ) . ( γ ⋅ ( − l − p2 + p3 + p4 ) + Mx ) . ( − i g )) − i la ( dZla + 2 dZphi )
The result of the tensor reduction is quite large, since we keep the
full gauge dependence and do not specify the kinematics
amp4[ 2 ] = TID[ amp4[ 1 ], l , ToPaVe -> True , UsePaVeBasis -> True ]
4 i π 2 B 0 ( p2 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 B 0 ( p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 B 0 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 + 4 i π 2 B 0 ( p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 C 0 ( p2 2 , p4 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 − p2 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p3 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 + p2 ⋅ p3 − p3 2 − p3 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p3 2 , p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 + p3 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p2 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 2 Mx 2 − p2 2 + p2 ⋅ p3 + p2 ⋅ p4 + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) g 4 − 4 i π 2 D 0 ( p2 2 , p4 2 , p3 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 , Mx 2 ) ( 16 Mx 4 − 4 p2 2 Mx 2 + 4 ( p2 ⋅ p3 ) Mx 2 + 4 ( p2 ⋅ p4 ) Mx 2 − 4 p3 2 Mx 2 − 4 ( p3 ⋅ p4 ) Mx 2 − 4 p4 2 Mx 2 + ( p2 ⋅ p4 ) p3 2 − p2 2 ( p3 ⋅ p4 ) + 2 ( p2 ⋅ p4 ) ( p3 ⋅ p4 ) − ( p2 ⋅ p3 ) p4 2 ) g 4 − 8 i π 2 ( p2 ⋅ p3 + p2 ⋅ p4 ) C 1 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) C 1 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i D π 2 C 00 ( p2 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 p2 2 C 11 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) C 11 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 16 i π 2 ( p2 ⋅ p3 + p2 ⋅ p4 ) C 12 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − i ( dZla + 2 dZphi ) la 4 i \pi ^2
\;\text{B}_0\left(\text{p2}^2,\text{Mx}^2,\text{Mx}^2\right) g^4-4 i \pi
^2 \;\text{B}_0\left(\text{p2}^2-2 (\text{p2}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2\right) g^4-4 i \pi ^2
\;\text{B}_0\left(\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2\right) g^4+4 i \pi ^2
\;\text{B}_0\left(\text{p2}^2-2 (\text{p2}\cdot \;\text{p3})-2
(\text{p2}\cdot \;\text{p4})+\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2\right) g^4-4 i \pi ^2
\;\text{C}_0\left(\text{p2}^2,\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
\left(4 \;\text{Mx}^2-\text{p2}\cdot \;\text{p4}\right) g^4-4 i \pi ^2
\;\text{C}_0\left(\text{p3}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot \;\text{p3})-2
(\text{p2}\cdot \;\text{p4})+\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
\left(4 \;\text{Mx}^2+\text{p2}\cdot
\;\text{p3}-\text{p3}^2-\text{p3}\cdot \;\text{p4}\right) g^4-4 i \pi ^2
\;\text{C}_0\left(\text{p3}^2,\text{p4}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
\left(4 \;\text{Mx}^2+\text{p3}\cdot \;\text{p4}\right) g^4-4 i \pi ^2
\;\text{C}_0\left(\text{p2}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot \;\text{p3})-2
(\text{p2}\cdot \;\text{p4})+\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
\left(2 \;\text{Mx}^2-\text{p2}^2+\text{p2}\cdot
\;\text{p3}+\text{p2}\cdot \;\text{p4}+\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2\right) g^4-4 i \pi ^2
\;\text{D}_0\left(\text{p2}^2,\text{p4}^2,\text{p3}^2,\text{p2}^2-2
(\text{p2}\cdot \;\text{p3})-2 (\text{p2}\cdot
\;\text{p4})+\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p4})+\text{p4}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
\left(16 \;\text{Mx}^4-4 \;\text{p2}^2 \;\text{Mx}^2+4 (\text{p2}\cdot
\;\text{p3}) \;\text{Mx}^2+4 (\text{p2}\cdot \;\text{p4})
\;\text{Mx}^2-4 \;\text{p3}^2 \;\text{Mx}^2-4 (\text{p3}\cdot
\;\text{p4}) \;\text{Mx}^2-4 \;\text{p4}^2 \;\text{Mx}^2+(\text{p2}\cdot
\;\text{p4}) \;\text{p3}^2-\text{p2}^2 (\text{p3}\cdot \;\text{p4})+2
(\text{p2}\cdot \;\text{p4}) (\text{p3}\cdot
\;\text{p4})-(\text{p2}\cdot \;\text{p3}) \;\text{p4}^2\right) g^4-8 i
\pi ^2 (\text{p2}\cdot \;\text{p3}+\text{p2}\cdot \;\text{p4})
\;\text{C}_1\left(\text{p2}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-8 i \pi ^2 \left(\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2\right) \;\text{C}_1\left(\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{p2}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-8 i D \pi ^2 \;\text{C}_{00}\left(\text{p2}^2,\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-8 i \pi ^2 \;\text{p2}^2
\;\text{C}_{11}\left(\text{p2}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-8 i \pi ^2 \left(\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2\right) \;\text{C}_{11}\left(\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{p2}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-16 i \pi ^2 (\text{p2}\cdot \;\text{p3}+\text{p2}\cdot \;\text{p4})
\;\text{C}_{12}\left(\text{p2}^2,\text{p2}^2-2 (\text{p2}\cdot
\;\text{p3})-2 (\text{p2}\cdot \;\text{p4})+\text{p3}^2+2
(\text{p3}\cdot \;\text{p4})+\text{p4}^2,\text{p3}^2+2 (\text{p3}\cdot
\;\text{p4})+\text{p4}^2,\text{Mx}^2,\text{Mx}^2,\text{Mx}^2\right)
g^4-i (\text{dZla}+2 \;\text{dZphi}) \;\text{la} 4 i π 2 B 0 ( p2 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 B 0 ( p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 B 0 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 + 4 i π 2 B 0 ( p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 ) g 4 − 4 i π 2 C 0 ( p2 2 , p4 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 − p2 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p3 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 + p2 ⋅ p3 − p3 2 − p3 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p3 2 , p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 4 Mx 2 + p3 ⋅ p4 ) g 4 − 4 i π 2 C 0 ( p2 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) ( 2 Mx 2 − p2 2 + p2 ⋅ p3 + p2 ⋅ p4 + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) g 4 − 4 i π 2 D 0 ( p2 2 , p4 2 , p3 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 , Mx 2 ) ( 16 Mx 4 − 4 p2 2 Mx 2 + 4 ( p2 ⋅ p3 ) Mx 2 + 4 ( p2 ⋅ p4 ) Mx 2 − 4 p3 2 Mx 2 − 4 ( p3 ⋅ p4 ) Mx 2 − 4 p4 2 Mx 2 + ( p2 ⋅ p4 ) p3 2 − p2 2 ( p3 ⋅ p4 ) + 2 ( p2 ⋅ p4 ) ( p3 ⋅ p4 ) − ( p2 ⋅ p3 ) p4 2 ) g 4 − 8 i π 2 ( p2 ⋅ p3 + p2 ⋅ p4 ) C 1 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) C 1 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i D π 2 C 00 ( p2 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 p2 2 C 11 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 8 i π 2 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 ) C 11 ( p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p2 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − 16 i π 2 ( p2 ⋅ p3 + p2 ⋅ p4 ) C 12 ( p2 2 , p2 2 − 2 ( p2 ⋅ p3 ) − 2 ( p2 ⋅ p4 ) + p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , p3 2 + 2 ( p3 ⋅ p4 ) + p4 2 , Mx 2 , Mx 2 , Mx 2 ) g 4 − i ( dZla + 2 dZphi ) la
Discard all the finite pieces of the 1-loop amplitude
amp4Div[ 0 ] = PaVeUVPart[ amp4[ 2 ], Prefactor -> 1 / (2 Pi )^ D ] // DiracSimplify //
FCReplaceD[ #, D -> 4 - 2 Epsilon] & // Series [ #, { Epsilon, 0 , 0 }] & // Normal //
FCHideEpsilon // SelectNotFree2[ #, { SMP[ "Delta" ], dZphi,
dZla}] & // ReplaceAll [ #, Join [ solMSbar1, solMSbar2]] & // Simplify
− 1 2 i ( 2 dZla la + Δ g 4 π 2 ) -\frac{1}{2} i \left(2 \;\text{dZla}
\;\text{la}+\frac{\Delta g^4}{\pi ^2}\right) − 2 1 i ( 2 dZla la + π 2 Δ g 4 )
Equating this to zero and solving for dZg we obtain the
renormalization constant in the minimal subtraction schemes.
solMSbar4 = FCMatchSolve[ amp4Div[ 0 ], { g , SMP, la}]
solMS4 = solMSbar4 /. SMP[ "Delta" ] -> 1 / Epsilon;
FCMatchSolve: Solving for: { dZla } \text{FCMatchSolve: Solving for:
}\{\text{dZla}\} FCMatchSolve: Solving for: { dZla }
FCMatchSolve: A solution exists. \text{FCMatchSolve: A solution
exists.} FCMatchSolve: A solution exists.
{ dZla → − Δ g 4 2 π 2 la } \left\{\text{dZla}\to
-\frac{\Delta g^4}{2 \pi ^2 \;\text{la}}\right\} { dZla → − 2 π 2 la Δ g 4 }
Join [ solMSbar1, solMSbar2, solMSbar3, solMSbar4] // TableForm
dZmx → 3 Δ g 2 32 π 2 dZx → − Δ g 2 32 π 2 dZphi → 0 dZmphi → Δ la ξ S ( 1 ) 32 π 2 dZg → 3 Δ g 2 32 π 2 dZla → − Δ g 4 2 π 2 la \begin{array}{l}
\;\text{dZmx}\to \frac{3 \Delta g^2}{32 \pi ^2} \\
\;\text{dZx}\to -\frac{\Delta g^2}{32 \pi ^2} \\
\;\text{dZphi}\to 0 \\
\;\text{dZmphi}\to \frac{\Delta \;\text{la} \xi _{S(1)}}{32 \pi ^2} \\
\;\text{dZg}\to \frac{3 \Delta g^2}{32 \pi ^2} \\
\;\text{dZla}\to -\frac{\Delta g^4}{2 \pi ^2 \;\text{la}} \\
\end{array} dZmx → 32 π 2 3Δ g 2 dZx → − 32 π 2 Δ g 2 dZphi → 0 dZmphi → 32 π 2 Δ la ξ S ( 1 ) dZg → 32 π 2 3Δ g 2 dZla → − 2 π 2 la Δ g 4