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Physics[StandardModel][Lagrangian] - retrieve the Lagrangian of the different sectors of the Standard Model like QED, QCD or Electro-Weak, or of all of it.

Calling Sequence

Lagrangian()

Lagrangian(sector)

Lagrangian(sector, options)

Parameters

sector

-

can be QED, QCD, electroweak or all (default value)

Options

• 

applied : (default = false), to return applied the products of differential operators times field functions

• 

expanded : (default = false), to return expanded the sums over leptons and quarks

• 

interaction : (default = false), to return only the interaction Lagrangian terms

• 

showterms : (default = false), related to the electroweak part, to return the corresponding Lagrangian terms as an explicit sum of different Lterm labels, with equations showing what is the contents of each label

• 

term = ... : related to the electroweak part, the right-hand side can be any of the labels LK,LN,LC,LH,LHV,LWWV,LWWVV,LY, to return only the corresponding Lagrangian term as shown when using the showterms option

Description

• 

One of the distinctive aspects of the Standard Model is the complexity of its Lagrangian. In this context, Lagrangian returns the Lagrangian of the model after symmetry breaking, optionally restricted to only the interaction terms, or only one of its QED, QCD and electroweak sectors, or only one of the different sub-terms involved in the electroweak part; all of that with the sums over leptons and quarks optionally expanded.

• 

All the algebraic expressions returned by Lagrangian are fully computable; so you can use them as starting point to construct other Lagrangians (add or subtract terms), or the Action and related field equations (see d_, D_ for covariant derivatives, diff and Fundiff for functional differentiation), or to compute scattering amplitudes (see FeynmanDiagrams and FeynmanIntegral). NOTE: the output of Lagrangian explicitly includes all the tensor indices of different kinds, like spacetime, spinor, su3 and su2 adjoint and fundamental representations.

• 

If called with no arguments Lagrangian returns the whole Lagrangian for the Standard Model (free fields and interaction terms), i.e. the QCD part plus the electroweak part. The sums over leptons and quarks entering the Lagrangian are returned not expanded, using the %add command, an inert representation of add. For QED and QCD, the free fields part is expressed using products of covariant derivative differential operators (D_) times the field functions. That resembles the usual way we represent these terms using paper and pencil and is useful to see the whole structure in its most compact form.

• 

The default output of Lagrangian can be restricted or tailored in several ways:

– 

You can indicate the sector, QED, QCD or electroweak (synonym: ElectroWeak) you are interested in, so that only the related terms are returned.

– 

For QED and QCD, you can use the keyword applied to have the covariant derivative differential operators D_ applied, not just multiplied by the field functions; or use the Library:-ApplyProductsOfDifferentialOperators command on the output of Lagrangian to get the same result.

– 

You can use the keyword expand to get the sums over leptons and quarks expanded; or use the value command on the output of Lagrangian to get the same result.

– 

Use the keyword interaction to get only the interaction terms; this is relevant when computing scattering amplitudes (see FeynmanDiagrams) where only the interaction part of the Lagrangian is used.

– 

The electroweak part of the Lagrangian is particularly complicated. It has, however, an algebraic structure of physically recognizable terms. Use the showterms keyword to see that structure, and to see only one of those terms use term = ... where the right-hand side is any of the following L[sector] (synonym L__sector) labelled according to the Wikipedia electroweak page as:

• 

LK is the kinetic part, including the dynamic and mass (quadratic) terms;

• 

LN is the neutral current;

• 

LC is the charged current;

• 

LH has the Higgs three and four point self interaction terms;

• 

LHV contains the Higgs interactions with the gauge vector bosons W+, W and Z;

• 

LWWV includes the gauge three-point self interactions between the fields A,W+,W and Z;

• 

LWWVV contains the gauge four-point self interactions between the fields A,W+,W and Z;

• 

LY contains the Yukawa interactions between the fermions and the Higgs field.

Examples

with(Physics):

with(StandardModel);

_______________________________________________________

Setting lowercaselatin_is letters to represent Dirac spinor indices

Setting lowercaselatin_ah letters to represent SU(3) adjoint representation, (1..8) indices

Setting uppercaselatin_ah letters to represent SU(3) fundamental representation, (1..3) indices

Setting uppercaselatin_is letters to represent SU(2) adjoint representation, (1..3) indices

Setting uppercasegreek letters to represent SU(2) fundamental representation, (1..2) indices

_______________________________________________________

Defined as the electron, muon and tau leptons and corresponding neutrinos: ei , μi , τi , νei , νμi , ντi

Defined as the up, charm, top, down, strange and bottom quarks: uA,i , cA,i , tA,i , dA,i , sA,i , bA,i

Defined as gauge tensors: Bμ , 𝔹μ,ν , Aμ , 𝔽μ,ν , Wμ,J , 𝕎μ,ν,J , W+μ , 𝕎+μ,ν , Wμ , 𝕎μ,ν , Zμ , μ,ν , Gμ,a , 𝔾μ,ν,a

Defined as Gell-Mann (Glambda), Pauli (Psigma) and Dirac (Dgamma) matrices: λa , σJ , γμ

Defined as the electric, weak and strong coupling constants: g__e, g__w, g__s

Defined as the charge in units of |g__e| for 1) the electron, muon and tauon, 2) the up, charm and top, and 3) the down, strange and bottom: q__e = −1, q__u = 23, q__d = 13

Defined as the weak isospin for 1) the electron, muon and tauon, 2) the up, charm and top, 3) the down, strange and bottom, and 4) all the neutrinos: I__e = 12, I__u = 12, I__d = 12, I__n = 12

You can use the active form without the % prefix, or the 'value' command to give the corresponding value to any of the inert representations q__e, q__u, q__d, I__e, I__u, I__d, I__n

_______________________________________________________

Default differentiation variables for d_, D_ and dAlembertian are:X=x,y,z,t

Minkowski spacetime with signatre - - - +

_______________________________________________________

I__d,I__e,I__n,I__u,q__d,q__e,q__u,BField,BFieldStrength,Bottom,CKM,Charm,Down,ElectromagneticField,ElectromagneticFieldStrength,Electron,ElectronNeutrino,FSU3,Glambda,GluonField,GluonFieldStrength,HiggsBoson,Lagrangian,Muon,MuonNeutrino,Strange,Tauon,TauonNeutrino,Top,Up,WField,WFieldStrength,WMinusField,WMinusFieldStrength,WPlusField,WPlusFieldStrength,WeinbergAngle,ZField,ZFieldStrength,g__e,g__s,g__w

(1)

The massless fields of the model are the electromagnetic and gluon fields and the three neutrinos

Setup(massless);

* Partial match of 'massless' against keyword 'masslessfields'

_______________________________________________________

masslessfields=G,νμ,ντ,A,νe

(2)

Note that using Physics noncommutative and anticommutative fields are displayed in different colors. You change these colors using Setup.

The Leptons and Quarks of the model are

StandardModel:-Leptons;

e,μ,τ,νe,νμ,ντ

(3)

StandardModel:-Quarks;

u,c,t,d,s,b

(4)

The Gauge fields, and their related field strengths displayed with Open Face type fonts

StandardModel:-GaugeFields;

A,𝔽,B,𝔹,W,𝕎,G,𝔾,W,𝕎,W+,𝕎+,Z,

(5)

To represent the interaction Lagrangians for the QCD and electroweak sectors as sums over leptons and quarks, all of them fermions, it is useful to introduce four anticommutative prefixes, used below as summation indices in the formulas

Setup(anticommutativeprefix = {f__L, f__Q, f__U, f__D});

anticommutativeprefix=f__D,f__L,f__Q,f__U

(6)

For readability, omit from the display of formulas the functionality of all the fields entering the Standard Model (see CompactDisplay) and use the lowercase i instead of the uppercase I to represent the imaginary unit

CompactDisplay((StandardModel:-Leptons, StandardModel:-Quarks, StandardModel:-GaugeFields, HiggsBoson, f__L, f__Q, f__U, f__D)(X), quiet):

interface(imaginaryunit = i):

The Lagrangian of the whole Standard Model after symmetry breaking, in its most compact form

Lagrangian();

f__Q=u,c,t,d,s,bf__Q¯A,jγμμj,kμmf__Qδj,kf__QA,k𝔾μ,ν,a𝔾μ,νaμ,νa4𝔽μ,ν𝔽μ,νμ,ν4𝕎+μ,ν𝕎μ,νμ,ν2+mW2W+μWμμμ,νμ,νμ,ν4+mZ2ZμZμμ2+μΦμμΦ2mΦ2Φ22+f__L=e,μ,τf__L¯jγμμj,kμf__Lkmf__Lf__Lj+f__L=νe,νμ,ντf__L¯jμf__Lkγμμj,k+f__Q=u,c,t,d,s,bf__Q¯A,jγμμj,kμf__QA,kmf__Qf__QA,j+g__eq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kAμγμμj,k+g__wγμμj,kδk,l+γ5k,lI__ef__L=e,μ,τf__L¯jf__Ll+I__nf__L=νe,νμ,ντf__L¯jf__Ll+I__uf__Q=u,c,tf__Q¯A,jf__QA,l+I__df__Q=d,s,bf__Q¯A,jf__QA,lsinθw2γμμj,kq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kZμcosθwg__w2δk,l+γ5k,lf__D=d,s,bf__U=u,c,t𝕄f__U,f__Df__U¯A,jf__DA,l+f__L=νe,e,νμ,μ,ντ,τf__L1¯jf__L2lW+μ+f__D=d,s,bf__U=u,c,tf__D¯A,jf__UA,l𝕄f__D,f__U&conjugate0;+f__L=νe,e,νμ,μ,ντ,τf__L2¯jf__L1lWμγμμj,k2g__wmΦ2Φ3+Φ48mW4mW+g__wΦmW+g__w2Φ24mW2mW2W+μWμμ+mZ2ZμZμμ2g__w𝕎+μ,νWμμ+W+μ𝕎νμνμAννsinθwZννcosθw+WνW+μ𝔽μ,νμ,νsinθwμ,νμ,νcosθwg__w22W+μWμμ+AμsinθwZμcosθwAμμsinθwZμμcosθw2W+νWνν+AνsinθwZνcosθwAννsinθwZννcosθw+W+μWν+W+νWμ+AμsinθwZμcosθwAνsinθwZνcosθwW+μμWνν+W+ννWμμ+AμμsinθwZμμcosθwAννsinθwZννcosθw4g__wf__L=e,μ,τ,νe,νμ,ντmf__Lf__L¯jf__Lj+f__Q=u,c,t,d,s,bmf__Qf__Q¯A,jf__QA,jΦ2mW

(7)

In the output above we see, among other things, the γ5 Dirac matrix, and the Cabibbo - Kobayashi - Maskawa matrix 𝕄, and the tensor indices of different kinds all explicit. See StandardModel for the notational conventions used, which are standard in the literature but for a few things, like a sign in the definition of γ5, that depends on the reference. Although this result is the complete Standard Model Lagrangian, it contains not expanded sums over the leptons and quarks, and in the dynamic part (free fields) the covariant derivative operator D_ does not apply but multiply the field functions, all this allowing for a representation that is both computable and as in textbooks. Passing the optional argument applied makes the covariant derivative operator be applied instead of multiplied, and passing the optional argument expanded makes all the sums be expanded (performed).

The Quantum Electrodynamics (QED) Lagrangian

The simplest sector of this Lagrangian (8) is the QED one

Lagrangian(QED);

e¯jγμμj,kμmeδj,kek𝔽μ,ν𝔽μ,νμ,ν4

(8)

The applied form can be obtained using the Library command ApplyProductsOfDifferentialOperators over the output (9) or passing the optional argument applied

Lagrangian(QED, applied);

e¯jγμμj,kμekmeδj,kek𝔽μ,ν𝔽μ,νμ,ν4

(9)

Only the interaction part of this Lagrangian is relevant when computing scattering amplitudes. To get that part, you can either expand the covariant derivative operator

expand((9));

γμμj,ke¯jμekγμμj,kg__ee¯jekAμmeδj,ke¯jek𝔽μ,ν𝔽μ,νμ,ν4

(10)

or pass the optional keyword expanded, in which case also the trace of 𝔽__μ,ν gets expanded

Lagrangian(QED, expanded);

e¯jμekγμμj,kg__ee¯jekAμγμμj,kmee¯jejμAννAμμμAννννAμμ4

(11)

then discard the non-interaction terms

remove(has, (11), [d_, m]);

γμμj,kg__ee¯jekAμ

(12)

or simpler: pass the keyword interaction

Lagrangian(QED, interaction);

γμμj,kg__ee¯jekAμ

(13)

All the algebraic expressions returned by Lagrangian are fully computable in that further calculations can proceed starting from them. For example (see FeynmanDiagrams), this is the self-energy of the electron

FeynmanDiagrams((13), incoming = [Electron],outgoing=[Electron], numberofloops = 1, diagrams);

uelP1ue¯mP2g__e2γααm,nγννp,lP__1β+p__2βγββn,p+meδn,pgα,νδP__2+P__18π3P__1+p__22me2+εp__22+εⅆp__2 4

(14)

The Quantum Chromodynamics (QCD) Lagrangian

Next in complexity is the QCD Lagrangian

Lagrangian(QCD);

f__Q=u,c,t,d,s,bf__Q¯A,jγμμj,kμmf__Qδj,kf__QA,k𝔾μ,ν,a𝔾μ,νaμ,νa4

(15)

To activate only the sum over quarks, without expanding or applying the covariant derivatives, you can use the value command

value((15));

u¯A,jγμμj,kμmuδj,kuA,k+c¯A,jγμμj,kμmcδj,kcA,k+t¯A,jγμμj,kμmtδj,ktA,k+d¯A,jγμμj,kμmdδj,kdA,k+s¯A,jγμμj,kμmsδj,ksA,k+b¯A,jγμμj,kμmbδj,kbA,k𝔾μ,ν,a𝔾μ,νaμ,νa4

(16)

To expand all of the QCD Lagrangian, that is the sum, covariant derivatives and trace of the gluon field strength 𝔾__μ,ν,a, pass expanded

Lagrangian(QCD, expanded);

u¯A,jμuA,kg__sλaA,BuB,kGμ,a2γμμj,kmuδj,kuA,k+c¯A,jμcA,kg__sλaA,BcB,kGμ,a2γμμj,kmcδj,kcA,k+t¯A,jμtA,kg__sλaA,BtB,kGμ,a2γμμj,kmtδj,ktA,k+d¯A,jμdA,kg__sλaA,BdB,kGμ,a2γμμj,kmdδj,kdA,k+s¯A,jμsA,kg__sλaA,BsB,kGμ,a2γμμj,kmsδj,ksA,k+b¯A,jμbA,kg__sλaA,BbB,kGμ,a2γμμj,kmbδj,kbA,kμGν,aνGμ,a+g__sfsu3a,b,cGμ,bGν,cμμGνaνaννGμaμa+g__sfsu3a,d,eGμdμdGνeνe4

(17)

For computing scattering amplitudes, only the interaction part of this Lagrangian is relevant. Although one can extract that part from the output above by removing terms, as done in (13), it is simpler to pass the keyword interaction

Lagrangian(QCD, interaction);

g__sλaA,Bf__Q=u,c,t,d,s,bf__Q¯A,jf__QB,kGμ,aγμμj,k2g__sfsu3a,b,cμGν,aGμbμbGνcνcg__sfsu3c,d,eGμ,aGα,bGμeμeGαdαd4

(18)

and to have also the sum expanded pass also expanded

Lagrangian(QCD, interaction, expanded);

g__sλaA,Bu¯A,juB,k+c¯A,jcB,k+t¯A,jtB,k+d¯A,jdB,k+s¯A,jsB,k+b¯A,jbB,kGμ,aγμμj,k2g__sfsu3a,b,cμGν,aGμbμbGνcνcg__sfsu3c,d,eGμ,aGα,bGμeμeGαdαd4

(19)

The amplitude at tree level for the process with two incoming and two outgoing Up quarks (particle and antiparticle) exchanging a gluon

FeynmanDiagrams((19), incomingparticles = [Up, DiracConjugate(Up)], outgoingparticles = [Up, DiracConjugate(Up)], numberofloops = 0, diagrams);

uuC,lP1vu¯E,mP2uu¯F,nP3vuG,pP4g__s2γκκn,pλgF,Gγββm,lλfE,Cgβ,κδf,gδP__3λλP__4λλ+P__1λλ+P__2λλ16π2P__1σ+P__2σP__1σσ+P__2σσ+ε+uuC,lP1vu¯E,mP2uu¯F,nP3vuG,pP4g__s2γκκm,pλgE,Gγββn,lλfF,Cgβ,κδf,gδP__3λλP__4λλ+P__1λλ+P__2λλ16π2P__1σP__3σP__1σσP__3σσ+ε

(20)

The probability density of the same process at 1 loop

FeynmanDiagrams((19), incomingparticles = [Up, DiracConjugate(Up)], outgoingparticles = [Up, DiracConjugate(Up)], numberofloops = 1, diagrams, output = probabilitydensity);

(21)

The Electro-Weak Lagrangian

The electroweak sector of the Standard Model Lagrangian is significantly more complicated.

Lagrangian(electroweak);

𝔽μ,ν𝔽μ,νμ,ν4𝕎+μ,ν𝕎μ,νμ,ν2+mW2W+μWμμμ,νμ,νμ,ν4+mZ2ZμZμμ2+μΦμμΦ2mΦ2Φ22+f__L=e,μ,τf__L¯jγμμj,kμf__Lkmf__Lf__Lj+f__L=νe,νμ,ντf__L¯jμf__Lkγμμj,k+f__Q=u,c,t,d,s,bf__Q¯A,jγμμj,kμf__QA,kmf__Qf__QA,j+g__eq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kAμγμμj,k+g__wγμμj,kδk,l+γ5k,lI__ef__L=e,μ,τf__L¯jf__Ll+I__nf__L=νe,νμ,ντf__L¯jf__Ll+I__uf__Q=u,c,tf__Q¯A,jf__QA,l+I__df__Q=d,s,bf__Q¯A,jf__QA,lsinθw2γμμj,kq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kZμcosθwg__w2δk,l+γ5k,lf__D=d,s,bf__U=u,c,t𝕄f__U,f__Df__U¯A,jf__DA,l+f__L=νe,e,νμ,μ,ντ,τf__L1¯jf__L2lW+μ+f__D=d,s,bf__U=u,c,tf__D¯A,jf__UA,l𝕄f__D,f__U&conjugate0;+f__L=νe,e,νμ,μ,ντ,τf__L2¯jf__L1lWμγμμj,k2g__wmΦ2Φ3+Φ48mW4mW+g__wΦmW+g__w2Φ24mW2mW2W+μWμμ+mZ2ZμZμμ2g__w𝕎+μ,νWμμ+W+μ𝕎νμνμAννsinθwZννcosθw+WνW+μ𝔽μ,νμ,νsinθwμ,νμ,νcosθwg__w22W+μWμμ+AμsinθwZμcosθwAμμsinθwZμμcosθw2W+νWνν+AνsinθwZνcosθwAννsinθwZννcosθw+W+μWν+W+νWμ+AμsinθwZμcosθwAνsinθwZνcosθwW+μμWνν+W+ννWμμ+AμμsinθwZμμcosθwAννsinθwZννcosθw4g__wf__L=e,μ,τ,νe,νμ,ντmf__Lf__L¯jf__Lj+f__Q=u,c,t,d,s,bmf__Qf__Q¯A,jf__QA,jΦ2mW

(22)

To decipher this result it is useful to see the structure of physically recognizable terms; click on the equal symbols = after where to highlight the Lterm label and the formula it represents

Lagrangian(electroweak, showterms);

L__K+L__N+L__C+L__H+L__HV+L__WWV+L__WWVV+L__YwhereL__K=𝔽μ,ν24𝕎+μ,ν𝕎μ,ν2+mW2W+μWμμ,ν24+mZ2Zμ22+μΦ22mΦ2Φ22+f__L=e,μ,τf__L¯jγμj,kμf__Lkmf__Lf__Lj+f__L=νe,νμ,ντγμj,kf__L¯jμf__Lk+f__Q=u,c,t,d,s,bf__Q¯A,jγμj,kμf__QA,kmf__Qf__QA,j,L__N=g__eγμj,kq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kAμ+g__wγμj,kδk,l+γ5k,lI__ef__L=e,μ,τf__L¯jf__Ll+I__nf__L=νe,νμ,ντf__L¯jf__Ll+I__uf__Q=u,c,tf__Q¯A,jf__QA,l+I__df__Q=d,s,bf__Q¯A,jf__QA,lsinθw2γμj,kq__ef__L=e,μ,τf__L¯jf__Lk+q__uf__Q=u,c,tf__Q¯A,jf__QA,k+q__df__Q=d,s,bf__Q¯A,jf__QA,kZμcosθw,L__C=g__w2γμj,kδk,l+γ5k,lf__D=d,s,bf__U=u,c,t𝕄f__U,f__Df__U¯A,jf__DA,l+f__L=νe,e,νμ,μ,ντ,τf__L1¯jf__L2lW+μ+f__D=d,s,bf__U=u,c,tf__D¯A,jf__UA,l𝕄f__D,f__U&conjugate0;+f__L=νe,e,νμ,μ,ντ,τf__L2¯jf__L1lWμ2,L__H=g__wmΦ2Φ3+Φ48mW4mW,L__HV=g__wΦmW+g__w2Φ24mW2mW2W+μWμ+Zμ2mZ22,L__WWV=−ⅈg__w𝕎+μ,νWμW+μ𝕎μ,νAνsinθwZνcosθw+WνW+μ𝔽μ,νsinθwμ,νcosθw,L__WWVV=g__w22W+μWμ+AμsinθwZμcosθw22W+νWν+AνsinθwZνcosθw2+W+μWν+W+νWμ+AμsinθwZμcosθwAνsinθwZνcosθw24,L__Y=g__wf__L=e,μ,τ,νe,νμ,ντmf__Lf__L¯jf__Lj+f__Q=u,c,t,d,s,bmf__Qf__Q¯A,jf__QA,jΦ2mW

(23)

In this result we see a sum of Lterms, and after where there is a list of equations with the formulas represented by each Lterm. Take from the above, for instance, only the charged current LC term that involves interaction between the leptons and the corresponding neutrinos: you can do that with the mouse, copy and paste, or using the term = ... option

Lagrangian(electroweak, term = L[C]);

L__C=g__w2δk,l+γ5k,lf__D=d,s,bf__U=u,c,t𝕄f__U,f__Df__U¯A,jf__DA,l+f__L=νe,e,νμ,μ,ντ,τf__L1¯jf__L2lW+μ+f__D=d,s,bf__U=u,c,tf__D¯A,jf__UA,l𝕄f__D,f__U&conjugate0;+f__L=νe,e,νμ,μ,ντ,τf__L2¯jf__L1lWμγμμj,k2

(24)

Lagrangian(electroweak, term = L[C], expanded);

L__C=g__w2δk,l+γ5k,l𝕄u,du¯A,jdA,l+𝕄c,dc¯A,jdA,l+𝕄t,dt¯A,jdA,l+𝕄u,su¯A,jsA,l+𝕄c,sc¯A,jsA,l+𝕄t,st¯A,jsA,l+𝕄u,bu¯A,jbA,l+𝕄c,bc¯A,jbA,l+𝕄t,bt¯A,jbA,l+νe¯jel+νμ¯jμl+ντ¯jτlW+μ+d¯A,juA,l𝕄d,u&conjugate0;+d¯A,jcA,l𝕄d,c&conjugate0;+d¯A,jtA,l𝕄d,t&conjugate0;+s¯A,juA,l𝕄s,u&conjugate0;+s¯A,jcA,l𝕄s,c&conjugate0;+s¯A,jtA,l𝕄s,t&conjugate0;+b¯A,juA,l𝕄b,u&conjugate0;+b¯A,jcA,l𝕄b,c&conjugate0;+b¯A,jtA,l𝕄b,t&conjugate0;+e¯jνel+μ¯jνμl+τ¯jντlWμγμμj,k2

(25)

A process at tree level with a positron and electronic neutrino incoming and the antimuon (antiparticle of the muon) and the muon neutrino outgoing after exchanging a W boson

FeynmanDiagrams(rhs((25)), incoming = [DiracConjugate(Electron), ElectronNeutrino], outgoing = [DiracConjugate(Muon), MuonNeutrino], numberofloops = 0, diagrams);

4ve¯mP1uνenP2vμpP3uνμ¯qP42g__wγααq,p22g__wγ5k,pγααq,k22g__wγννm,n22g__wγ5r,nγννm,r2gα,ν+P__1ν+P__2νP__1α+P__2αmW2δP__3ββP__4ββ+P__1ββ+P__2ββπ2P__1κ+P__2κP__1κκ+P__2κκmW2+ε

(26)

The term LHV of the electroweak Lagrangian contains the interaction between the Higgs and the Z and W bosons

Lagrangian(electroweak, term = L[HV], interaction);

L__HV=g__wΦmW+g__w2Φ24mW2mW2W+μWμμ+mZ2ZμZμμ2

(27)

The probability density at one loop for a process with two Higgs incoming and outgoing

FeynmanDiagrams(rhs((27)), incoming = [HiggsBoson, HiggsBoson], outgoing = [HiggsBoson, HiggsBoson], numberofloops = 1, diagrams, output = probabilitydensity);

4π2i__1=12ni__1F2δP__3P__4+P__1+P__2f=12dPf3whereF=g__w4mZ8gλ,υλ,υgβ,κβ,κgσ,τσ,τgα,να,νgλ,ν+P__4ν+p__4νP__4λ+p__4λmZ2gα,σ+P__1α+P__4α+p__4αP__1σ+P__4σ+p__4σmZ2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmZ2gκ,υ+p__4κp__4υmZ21024π6E__1E__2E__3E__4mW4P__4+p__42mZ2+εP__1+P__4+p__42mZ2+εP__3+P__1P__4p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mZ8gτ,υτ,υgκ,σκ,σgβ,λβ,λgα,να,νgλ,ν+P__3νP__1νp__4νP__3λP__1λp__4λmZ2gα,σ+P__3α+p__4αP__3σ+p__4σmZ2gβ,τ+P__3βP__2βP__1βp__4βP__3τP__2τP__1τp__4τmZ2gκ,υ+p__4κp__4υmZ2512π6E__1E__2E__3E__4mW4P__3P__1p__42mZ2+εP__3+p__42mZ2+εP__3P__2P__1p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__1ν+p__3νP__2κ+P__1κ+p__3κmZ2gα,λ+P__2α+p__3αP__2λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+P__1+p__32mZ2+εP__2+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mW2gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2νP__4ν+p__3νP__2κP__4κ+p__3κmW2gα,λ+P__2α+P__4αP__1αp__3αP__2λ+P__4λP__1λp__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2P__4+p__32mW2+εP__2+P__4P__1p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__4νP__1νp__3νP__2κ+P__4κP__1κp__3κmZ2gα,λ+P__2α+p__3αP__2λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+P__4P__1p__32mZ2+εP__2+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmZ2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+p__32mZ2+εP__2+P__3P__1p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mW2gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmW2gα,λ+P__2α+P__4αP__1αp__3αP__2λ+P__4λP__1λp__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+p__32mW2+εP__2+P__4P__1p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__3νP__1νp__3νP__2κ+P__3κP__1κp__3κmZ2gα,λ+P__2α+p__3αP__2λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+P__3P__1p__32mZ2+εP__2+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmZ2gα,λ+P__2α+P__1α+p__3αP__2λ+P__1λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+p__32mZ2+εP__2+P__1+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mW2gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__3ν+p__3νP__3κ+p__3κmW2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__3+p__32mW2+εP__2+P__3P__1p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mW4gλ,υλ,υgβ,κβ,κgσ,τσ,τgα,να,νgλ,ν+P__3ν+p__4νP__3λ+p__4λmW2gα,σ+P__3αP__1α+p__4αP__3σP__1σ+p__4σmW2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__3+p__42mW2+εP__3P__1+p__42mW2+εP__3+P__1P__4p__42mW2+εp__42mW2+εⅆp__4 4+g__w4mW4gτ,υτ,υgκ,σκ,σgβ,λβ,λgα,να,νgλ,ν+P__3νP__1νp__4νP__3λP__1λp__4λmW2gα,σ+P__3α+p__4αP__3σ+p__4σmW2gβ,τ+P__3βP__2βP__1βp__4βP__3τP__2τP__1τp__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__3P__1p__42mW2+εP__3+p__42mW2+εP__3P__2P__1p__42mW2+εp__42mW2+εⅆp__4 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2νP__3ν+p__3νP__2κP__3κ+p__3κmZ2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2P__3+p__32mZ2+εP__2+P__3P__1p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mZ4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__2ν+p__2νP__1β+P__2β+p__2βmZ2gα,κ+p__2αp__2κmZ22048π6E__1E__2E__3E__4mW4P__1+P__2+p__22mZ2+εp__22mZ2+εⅆp__2 4+g__w4gκ,σκ,σmW2gβ,λβ,λgα,να,νgκ,ν+P__2ν+P__1ν+p__3νP__2κ+P__1κ+p__3κmW2gα,λ+P__2α+p__3αP__2λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+P__1+p__32mW2+εP__2+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__4νp__2νP__1β+P__4βp__2βmZ2gα,κ+p__2αp__2κmZ22048π6E__1E__2E__3E__4mW4P__1+P__4p__22mZ2+εp__22mZ2+εⅆp__2 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmZ2gα,λ+P__2α+P__4αP__1αp__3αP__2λ+P__4λP__1λp__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+p__32mZ2+εP__2+P__4P__1p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mW2gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__4νP__1νp__3νP__2κ+P__4κP__1κp__3κmW2gα,λ+P__2αP__4α+p__3αP__2λP__4λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+P__4P__1p__32mW2+εP__2P__4+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mW2gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__4ν+p__3νP__4κ+p__3κmW2gα,λ+P__4αP__1αP__2α+p__3αP__4λP__1λP__2λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__4+p__32mW2+εP__4P__1P__2+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__3νp__2νP__1β+P__3βp__2βmW2gα,κ+p__2αp__2κmW21024π6E__1E__2E__3E__4P__1+P__3p__22mW2+εp__22mW2+εⅆp__2 4+g__w4mW4gλ,υλ,υgκ,τκ,τgβ,σβ,σgα,να,νgλ,ν+P__3νP__2νP__1νp__4νP__3λP__2λP__1λp__4λmW2gα,σ+P__2αP__3α+p__4αP__2σP__3σ+p__4σmW2gβ,τ+P__3β+p__4βP__3τ+p__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__3P__2P__1p__42mW2+εP__2P__3+p__42mW2+εP__3+p__42mW2+εp__42mW2+εⅆp__4 4+g__w4mZ8gλ,υλ,υgβ,κβ,κgσ,τσ,τgα,να,νgλ,ν+P__3ν+p__4νP__3λ+p__4λmZ2gα,σ+P__3αP__1α+p__4αP__3σP__1σ+p__4σmZ2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmZ2gκ,υ+p__4κp__4υmZ21024π6E__1E__2E__3E__4mW4P__3+p__42mZ2+εP__3P__1+p__42mZ2+εP__3+P__1P__4p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mZ8gσ,υσ,υgκ,τκ,τgβ,λβ,λgα,να,νgλ,ν+P__2νP__3ν+p__4νP__2λP__3λ+p__4λmZ2gα,σ+P__3αP__2αP__1αp__4αP__3σP__2σP__1σp__4σmZ2gβ,τ+P__3β+p__4βP__3τ+p__4τmZ2gκ,υ+p__4κp__4υmZ2512π6E__1E__2E__3E__4mW4P__2P__3+p__42mZ2+εP__3P__2P__1p__42mZ2+εP__3+p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mW4gτ,υτ,υgκ,λκ,λgβ,σβ,σgα,να,νgλ,ν+P__3ν+p__4νP__3λ+p__4λmW2gα,σ+P__3αP__1αp__4αP__3σP__1σp__4σmW2gβ,τ+P__3βP__2βP__1βp__4βP__3τP__2τP__1τp__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__3+p__42mW2+εP__3P__1p__42mW2+εP__3P__2P__1p__42mW2+εp__42mW2+εⅆp__4 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__3νP__1νp__3νP__2κ+P__3κP__1κp__3κmZ2gα,λ+P__2αP__3α+p__3αP__2λP__3λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+P__3P__1p__32mZ2+εP__2P__3+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__2ν+p__2νP__1β+P__2β+p__2βmW2gα,κ+p__2αp__2κmW21024π6E__1E__2E__3E__4P__1+P__2+p__22mW2+εp__22mW2+εⅆp__2 4+g__w4mW4gσ,υσ,υgκ,τκ,τgβ,λβ,λgα,να,νgλ,ν+P__2νP__3ν+p__4νP__2λP__3λ+p__4λmW2gα,σ+P__3αP__2αP__1αp__4αP__3σP__2σP__1σp__4σmW2gβ,τ+P__3β+p__4βP__3τ+p__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__2P__3+p__42mW2+εP__3P__2P__1p__42mW2+εP__3+p__42mW2+εp__42mW2+εⅆp__4 4+g__w4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__4νp__2νP__1β+P__4βp__2βmW2gα,κ+p__2αp__2κmW21024π6E__1E__2E__3E__4P__1+P__4p__22mW2+εp__22mW2+εⅆp__2 4+g__w4mW2gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__3νP__1νp__3νP__2κ+P__3κP__1κp__3κmW2gα,λ+P__2αP__3α+p__3αP__2λP__3λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+P__3P__1p__32mW2+εP__2P__3+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ8gσ,υσ,υgβ,κβ,κgλ,τλ,τgα,να,νgλ,ν+P__1ν+P__4ν+p__4νP__1λ+P__4λ+p__4λmZ2gα,σ+P__4α+p__4αP__4σ+p__4σmZ2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmZ2gκ,υ+p__4κp__4υmZ21024π6E__1E__2E__3E__4mW4P__1+P__4+p__42mZ2+εP__4+p__42mZ2+εP__3+P__1P__4p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mW2gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmW2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+p__32mW2+εP__2+P__3P__1p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ8gσ,υσ,υgβ,κβ,κgλ,τλ,τgα,να,νgλ,ν+P__3νP__1ν+p__4νP__3λP__1λ+p__4λmZ2gα,σ+P__3α+p__4αP__3σ+p__4σmZ2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmZ2gκ,υ+p__4κp__4υmZ21024π6E__1E__2E__3E__4mW4P__3P__1+p__42mZ2+εP__3+p__42mZ2+εP__3+P__1P__4p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mW2gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2νP__3ν+p__3νP__2κP__3κ+p__3κmW2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2P__3+p__32mW2+εP__2+P__3P__1p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__4νP__1νp__3νP__2κ+P__4κP__1κp__3κmZ2gα,λ+P__2αP__4α+p__3αP__2λP__4λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2+P__4P__1p__32mZ2+εP__2P__4+p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mZ8gλ,υλ,υgκ,τκ,τgβ,σβ,σgα,να,νgλ,ν+P__3νP__2νP__1νp__4νP__3λP__2λP__1λp__4λmZ2gα,σ+P__2αP__3α+p__4αP__2σP__3σ+p__4σmZ2gβ,τ+P__3β+p__4βP__3τ+p__4τmZ2gκ,υ+p__4κp__4υmZ2512π6E__1E__2E__3E__4mW4P__3P__2P__1p__42mZ2+εP__2P__3+p__42mZ2+εP__3+p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__3ν+p__3νP__3κ+p__3κmZ2gα,λ+P__2α+P__3αP__1αp__3αP__2λ+P__3λP__1λp__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__3+p__32mZ2+εP__2+P__3P__1p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mZ4gβ,κβ,κgα,να,νgβ,ν+P__1ν+P__3νp__2νP__1β+P__3βp__2βmZ2gα,κ+p__2αp__2κmZ22048π6E__1E__2E__3E__4mW4P__1+P__3p__22mZ2+εp__22mZ2+εⅆp__2 4+g__w4gλ,σλ,σmW2gβ,κβ,κgα,να,νgκ,ν+P__2ν+p__3νP__2κ+p__3κmW2gα,λ+P__2α+P__1α+p__3αP__2λ+P__1λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+p__32mW2+εP__2+P__1+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ8gτ,υτ,υgκ,λκ,λgβ,σβ,σgα,να,νgλ,ν+P__3ν+p__4νP__3λ+p__4λmZ2gα,σ+P__3αP__1αp__4αP__3σP__1σp__4σmZ2gβ,τ+P__3βP__2βP__1βp__4βP__3τP__2τP__1τp__4τmZ2gκ,υ+p__4κp__4υmZ2512π6E__1E__2E__3E__4mW4P__3+p__42mZ2+εP__3P__1p__42mZ2+εP__3P__2P__1p__42mZ2+εp__42mZ2+εⅆp__4 4+g__w4mW2gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__3νP__1νp__3νP__2κ+P__3κP__1κp__3κmW2gα,λ+P__2α+p__3αP__2λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+P__3P__1p__32mW2+εP__2+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ6gλ,σλ,σgβ,κβ,κgα,να,νgκ,ν+P__2νP__4ν+p__3νP__2κP__4κ+p__3κmZ2gα,λ+P__2α+P__4αP__1αp__3αP__2λ+P__4λP__1λp__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__2P__4+p__32mZ2+εP__2+P__4P__1p__32mZ2+εp__32mZ2+εⅆp__3 4+g__w4mW4gλ,υλ,υgβ,κβ,κgσ,τσ,τgα,να,νgλ,ν+P__4ν+p__4νP__4λ+p__4λmW2gα,σ+P__1α+P__4α+p__4αP__1σ+P__4σ+p__4σmW2gβ,τ+P__3β+P__1βP__4βp__4βP__3τ+P__1τP__4τp__4τmW2gκ,υ+p__4κp__4υmW2256π6E__1E__2E__3E__4P__4+p__42mW2+εP__1+P__4+p__42mW2+εP__3+P__1P__4p__42mW2+εp__42mW2+εⅆp__4 4+g__w4mW2gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__2ν+P__4νP__1νp__3νP__2κ+P__4κP__1κp__3κmW2gα,λ+P__2α+p__3αP__2λ+p__3λmW2gβ,σ+p__3βp__3σmW2512π6E__1E__2E__3E__4P__2+P__4P__1p__32mW2+εP__2+p__32mW2+εp__32mW2+εⅆp__3 4+g__w4mZ6gκ,σκ,σgβ,λβ,λgα,να,νgκ,ν+P__4ν+p__3νP__4κ+p__3κmZ2gα,λ+P__4αP__1αP__2α+p__3αP__4λP__1λP__2λ+p__3λmZ2gβ,σ+p__3βp__3σmZ21024π6E__1E__2E__3E__4mW4P__4+p__32mZ2+εP__4P__1P__2+p__32mZ2+εp__32mZ2+εⅆp__3 4

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See Also

add, d_, D_, Dgamma, diff, DiracConjugate, FeynmanDiagrams, FeynmanIntegral[Overview], Fundiff, Physics, Physics conventions, Physics examples, Physics Updates, Tensors - a complete guide, Mini-Course Computer Algebra for Physicists, Setup, StandardModel, TensorReduce, value, Wikipedia electroweak page, Wikipedia QCD page, Wikipedia QED page

References

  

[1] Wikipedia, Mathematical formulation of the Standard Model.

  

[2] Weinberg, S., The Quantum Theory Of Fields. Cambridge University Press, 2005.

Compatibility

• 

The Physics[StandardModel][Lagrangian] command was introduced in Maple 2022.

• 

For more information on Maple 2022 changes, see Updates in Maple 2022.