A class for \(O(\alpha^2)\) two-loop corrections to the EW precision observables. More...
#include <EWSMTwoLoopEW.h>
A class for \(O(\alpha^2)\) two-loop corrections to the EW precision observables.
This class handles two-loop EW contributions of \(O(\alpha^2)\) to the following quantities, which are relevant to the EW precision observables:
and the \(O(\alpha^2)\) corrections to \(\Delta\rho\) and to \(Zb\bar{b}\):
See also the description of EWSM class for their definitions. The \(O(\alpha^2)\) two-loop EW contributions to the vacuum polarization amplitudes of the gauge bosons were calculated in [Barbieri:1992nz], [Barbieri:1992dq], [Fleischer:1993ub], [Fleischer:1994cb], [Degrassi:1996mg], [Degrassi:1996ps] and [Degrassi:1999jd] with large- \(m_t\) expansion. In the current class, the \(O(\alpha^2(m_t^4/m_Z^4 + m_t^2/M_Z^2))\) corrections to \(\Delta\rho\), \(\Delta r_{\mathrm{rem}}\), \(\delta\rho_{\mathrm{rem}}^{f}\) and \(\delta\kappa_{\mathrm{rem}}^{f}\) and the \(O(\alpha^2 m_t^4/M_Z^4)\) corrections to \(Zb\bar{b}\), denoted by \(\rho^{(2)}\) and \(\tau^{(2)}\), are computed with the auxiliary functions defined as private members. In [Degrassi:1996mg], the former corrections were calculated in the MSbar scheme in order to undertake resummations correctly. In subsequent papers [Degrassi:1996ps] and [Degrassi:1999jd], the resultant two-loop contributions were rewritten in terms of parameters in the on-shell scheme by taking into account additional contributions, which correspond to the member functions with the word "Add".
Definition at line 57 of file EWSMTwoLoopEW.h.
Public Member Functions | |
double | DeltaAlpha_l (const double s) const |
Leptonic contribution of \(O(\alpha^2)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{lept}}^{\alpha^2}(s)\). More... | |
double | DeltaAlpha_t (const double s) const |
Top-quark contribution of \(O(\alpha^2)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{top}}^{\alpha^2}(s)\). More... | |
gslpp::complex | deltaKappa_rem_f (const Particle f, const double Mw_i) const |
Remainder contribution of \(O(\alpha^2)\) to the effective couplings \(\kappa_Z^f\), denoted as \(\delta\kappa_{\mathrm{rem}}^{f,\, \alpha^2}\). More... | |
double | DeltaR_rem (const double Mw_i) const |
Remainder contribution of \(O(\alpha^2)\) to \(\Delta r\), denoted as \(\Delta r_{\mathrm{rem}}^{\alpha^2}\). More... | |
double | DeltaRho (const double Mw_i) const |
Leading two-loop contribution of \(O(\alpha^2)\) to \(\Delta\rho\), denoted as \(\Delta\rho^{\alpha^2}\). More... | |
gslpp::complex | deltaRho_rem_f (const Particle f, const double Mw_i) const |
Remainder contribution of \(O(\alpha^2)\) to the effective couplings \(\rho_Z^f\), denoted as \(\delta\rho_{\mathrm{rem}}^{f,\, \alpha^2}\). More... | |
EWSMTwoLoopEW (const EWSMcache &cache_i) | |
Constructor. More... | |
double | rho_2 () const |
The function \(\rho^{(2)}\). More... | |
double | tau_2 () const |
The function \(\tau^{(2)}\). More... | |
Private Member Functions | |
double | deltaEoverE2 () const |
The auxiliary function \((\delta e/e)^{(2)}\). More... | |
double | DeltaEta2 (const double Mw_i) const |
The auxiliary function \(\Delta\hat{\eta}^{(2)}\). More... | |
gslpp::complex | DeltaEta2Add_f (const Particle f, const double Mw_i) const |
The auxiliary function \(\Delta\bar{\eta}_{\rm add}^{(2)}\) for \(Z\to f\bar{f}\). More... | |
gslpp::complex | DeltaEta2Add_tmp (const double I3f, const double Qf, const double Mw_i) const |
The auxiliary function \(\Delta\bar{\eta}_{\rm add}^{(2)}\). More... | |
gslpp::complex | DeltaEtaf1 (const double I3f, const double Qf, const double Mw_i) const |
The auxiliary function \(\Delta\bar{\eta}^{(1)}_f\). More... | |
double | DeltaKappa2 (const double Mw_i) const |
The auxiliary function \(\Delta\hat{\kappa}^{(2)}\). More... | |
gslpp::complex | DeltaKappa2Add_f (const Particle f, const double Mw_i) const |
The auxiliary function \(\Delta\bar{\kappa}_{\rm add}^{(2)}\) for \(Z\to f\bar{f}\). More... | |
gslpp::complex | DeltaKappa2Add_tmp (const double I3f, const double Qf, const double Mw_i) const |
The auxiliary function \(\Delta\bar{\kappa}_{\rm add}^{(2)}\). More... | |
double | DeltaRho2 (const double Mw_i) const |
The auxiliary function \(\Delta\hat{\rho}^{(2)}\). More... | |
double | DeltaRho2Add (const double Mw_i) const |
The auxiliary function \(\Delta\bar{\rho}_{\mathrm{add}}^{(2)}\). More... | |
double | DeltaRw2 (const double Mw_i) const |
The auxiliary function \(\Delta \hat{r}_W^{(2)}\). More... | |
double | f0 (const double a) const |
The auxiliary function \(f(a,0)\). More... | |
double | f1 (const double a) const |
The auxiliary function \(f(a,1)\). More... | |
double | f2Add (const double Mw_i) const |
The auxiliary function \(\bar{f}_{\rm add}^{(2)}\). More... | |
gslpp::complex | FV (const double x) const |
The auxiliary function \(f(x)\). More... | |
double | g (const double a) const |
The auxiliary function \(g(a)\). More... | |
gslpp::complex | GV (const double x) const |
The auxiliary function \(g(x)\). More... | |
double | Lambda (const double x) const |
The auxiliary function \(\Lambda(x)\). More... | |
double | phi (const double x) const |
The auxiliary function \(\phi(x)\). More... | |
gslpp::complex | Vadd (const double I3f, const double Qf, const double Mw_i) const |
The auxiliary function \(V_{\rm add}\). More... | |
gslpp::complex | Vfi (const double I3f, const double Qf, const double q2, const double Mw_i) const |
The auxiliary function \({\cal V}_{fi}(q^2)\). More... | |
Private Attributes | |
const EWSMcache & | cache |
A reference to an object of type EWSMcache. More... | |
const EWSMOneLoopEW | myOneLoopEW |
An object of type EWSMOneLoopEW. More... | |
EWSMTwoLoopEW::EWSMTwoLoopEW | ( | const EWSMcache & | cache_i | ) |
Constructor.
[in] | cache_i | a reference to an object of type EWSMcache |
Definition at line 15 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::DeltaAlpha_l | ( | const double | s | ) | const |
Leptonic contribution of \(O(\alpha^2)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{lept}}^{\alpha^2}(s)\).
The expressions used here can be found in [Steinhauser:1998rq].
[in] | s | invariant mass squared |
Definition at line 23 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::DeltaAlpha_t | ( | const double | s | ) | const |
Top-quark contribution of \(O(\alpha^2)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{top}}^{\alpha^2}(s)\).
This contribution is not implemented, since it is tiny and negligible.
[in] | s | invariant mass squared |
Definition at line 49 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \((\delta e/e)^{(2)}\).
See [Degrassi:1999jd].
Definition at line 345 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(\Delta\hat{\eta}^{(2)}\).
See [Degrassi:1999jd].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 383 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\eta}_{\rm add}^{(2)}\) for \(Z\to f\bar{f}\).
See [Degrassi:1999jd].
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 461 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\eta}_{\rm add}^{(2)}\).
This functions is used in DeltaEta2Add_l() and DeltaEta2Add_q(). See [Degrassi:1999jd].
[in] | I3f | the isospin of a final-state fermion |
[in] | Qf | the electric charge of a final-state fermion |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 436 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\eta}^{(1)}_f\).
This functions is used in DeltaEta2Add_tmp(). See [Degrassi:1990ec] and [Degrassi:1999jd].
[in] | I3f | the isospin of a final-state fermion |
[in] | Qf | the electric charge of a final-state fermion |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 551 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\hat{\kappa}^{(2)}\).
See [Degrassi:1999jd].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 468 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\kappa}_{\rm add}^{(2)}\) for \(Z\to f\bar{f}\).
See [Degrassi:1999jd].
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 529 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\kappa}_{\rm add}^{(2)}\).
This functions is used in DeltaKappa2Add_l() and DeltaKappa2Add_q(). See [Degrassi:1999jd].
[in] | I3f | the isospin of a final-state fermion |
[in] | Qf | the electric charge of a final-state fermion |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 503 of file EWSMTwoLoopEW.cpp.
gslpp::complex EWSMTwoLoopEW::deltaKappa_rem_f | ( | const Particle | f, |
const double | Mw_i | ||
) | const |
Remainder contribution of \(O(\alpha^2)\) to the effective couplings \(\kappa_Z^f\), denoted as \(\delta\kappa_{\mathrm{rem}}^{f,\, \alpha^2}\).
This function handles the \(O(\alpha^2)\) remainder contribution to \(\kappa_{Z}^{f}\) in the on-shell scheme, which was calculated in [Degrassi:1999jd] :
\[ \delta\kappa_{\rm rem}^{f,\, \alpha^2} = 3 (X_t^{\alpha})^2 \left[ 16\, {\it zt}\,c_W^2\, \Delta\hat{k}^{(2)} + 4\, {\it zt}\,c_W^2\, \Delta\bar{k}_{\rm add}^{(2)} \right], \]
where the definitions of the symbols can be read from the codes below.
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 115 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::DeltaR_rem | ( | const double | Mw_i | ) | const |
Remainder contribution of \(O(\alpha^2)\) to \(\Delta r\), denoted as \(\Delta r_{\mathrm{rem}}^{\alpha^2}\).
This function handles the remainder two-loop EW contribution of \(O(\alpha^2(m_t^4/m_Z^4 + m_t^2/M_Z^2))\) to \(\Delta r\) in the on-shell scheme. The expression can be found in [Degrassi:1996mg], [Degrassi:1996ps] and [Degrassi:1999jd] :
\[ \Delta r_{\rm rem}^{\alpha^2} = 3\left(\frac{\alpha}{4\pi s_W^2}\right)^2 \frac{m_t^2}{M_W^2} \left[ \Delta \hat{r}_W^{(2)} + s_W^2 \bigg(\frac{\delta e}{e}\bigg)^{(2)} + \frac{1}{4}\, \bar{f}_{\rm add}^{(2)} \right], \]
where the definitions of the symbols can be read from the codes below.
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 81 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::DeltaRho | ( | const double | Mw_i | ) | const |
Leading two-loop contribution of \(O(\alpha^2)\) to \(\Delta\rho\), denoted as \(\Delta\rho^{\alpha^2}\).
This function handles the leading irreducible two-loop EW contribution of \(O(\alpha^2(m_t^4/m_Z^4 + m_t^2/M_Z^2))\) to \(\Delta\rho\) in the on-shell scheme. The expression can be found in [Degrassi:1996mg] and [Degrassi:1996ps] :
\[ \Delta\rho^{\alpha^2} = 3 (X_t^{\alpha})^2 \left( \Delta\hat{\rho}^{(2)} + 4\, {\it zt}\, c_W^2 \Delta\bar{\rho}_{\mathrm{add}}^{(2)} \right) - \left(\frac{\alpha}{4\pi}\right)^2 \frac{c_W^2}{s_W^2} \left[ \mathrm{Re}\Pi^{\mathrm{fer}}_{Z\gamma}(M_Z^2) \right]^2, \]
where the definitions of the symbols can be read from the codes below, and the last term originates from the \(Z\)- \(\gamma\) mixing (see, e.g., Chapter 6 of [Bardin:1999ak]).
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 54 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(\Delta\hat{\rho}^{(2)}\).
See [Degrassi:1996mg].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 203 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta\bar{\rho}_{\mathrm{add}}^{(2)}\).
See [Degrassi:1996ps].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 267 of file EWSMTwoLoopEW.cpp.
gslpp::complex EWSMTwoLoopEW::deltaRho_rem_f | ( | const Particle | f, |
const double | Mw_i | ||
) | const |
Remainder contribution of \(O(\alpha^2)\) to the effective couplings \(\rho_Z^f\), denoted as \(\delta\rho_{\mathrm{rem}}^{f,\, \alpha^2}\).
This function handles the \(O(\alpha^2)\) remainder contribution to \(\rho_{Z}^{f}\) in the on-shell scheme, which was calculated in [Degrassi:1999jd] :
\[ \delta\rho_{\rm rem}^{f,\, \alpha^2} = 3 (X_t^{\alpha})^2 \left[ 16\, {\it zt}\,c_W^2\, \Delta\hat{\eta}^{(2)} + 4\, {\it zt}\,c_W^2\, \Delta\bar{\eta}_{\rm add}^{(2)} \right], \]
where the definitions of the symbols can be read from the codes below.
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 96 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(\Delta \hat{r}_W^{(2)}\).
See [Degrassi:1996mg].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 291 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(f(a,0)\).
See [Fleischer:1993ub] and [Fleischer:1994cb].
[in] | a | the ratio \(a=(m_h/m_t)^2\) |
Definition at line 180 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \(f(a,1)\).
See [Fleischer:1993ub] and [Fleischer:1994cb].
[in] | a | the ratio \(a=(m_h/m_t)^2\) |
Definition at line 188 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(\bar{f}_{\rm add}^{(2)}\).
See [Degrassi:1996ps].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 365 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(f(x)\).
This function is used in Vadd() and Vfi(). See [Degrassi:1990ec].
[in] | x | a real variable |
Definition at line 607 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(g(a)\).
See [Fleischer:1993ub] and [Fleischer:1994cb].
[in] | a | the ratio \(a=(m_h/m_t)^2\) |
Definition at line 167 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(g(x)\).
This function is used in Vadd() and Vfi(). See [Degrassi:1990ec].
[in] | x | a real variable |
Definition at line 621 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(\Lambda(x)\).
This functions is used in DeltaRho2(), DeltaRw2() and DeltaEta2(). See [Degrassi:1996mg] and [Degrassi:1999jd].
[in] | x | a real variable |
Definition at line 584 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(\phi(x)\).
This functions is used in DeltaRho2(), DeltaRw2(), deltaEoverE2(), DeltaEta2() and DeltaKappa2(). See [Degrassi:1996mg] and [Degrassi:1999jd].
[in] | x | a real variable |
Definition at line 594 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::rho_2 | ( | ) | const |
The function \(\rho^{(2)}\).
This function parameterize the \(O(\alpha^2 m_t^4/M_Z^4)\) contribution to \(\Delta\rho\):
\[ \Delta\rho^{\alpha^2} = 3 (X_t^{\alpha})^2\rho^{(2)}, \]
where the expression of \(\rho^{(2)}\) can be found in [Fleischer:1993ub] and [Fleischer:1994cb] (see also [Barbieri:1992nz] and [Barbieri:1992dq]).
Definition at line 137 of file EWSMTwoLoopEW.cpp.
double EWSMTwoLoopEW::tau_2 | ( | ) | const |
The function \(\tau^{(2)}\).
This function parmeterize the \(O(\alpha^2 m_t^4/M_Z^4)\) contribution to the \(Zb\bar{b}\) vertex (see EWSM::taub()), where the expression of \(\tau^{(2)}\) can be found in [Fleischer:1993ub] and [Fleischer:1994cb] (see also [Barbieri:1992nz] and [Barbieri:1992dq]).
Definition at line 151 of file EWSMTwoLoopEW.cpp.
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The auxiliary function \(V_{\rm add}\).
This functions is used in DeltaEta2Add_tmp(). See [Degrassi:1999jd].
[in] | I3f | the isospin of a final-state fermion |
[in] | Qf | the electric charge of a final-state fermion |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 536 of file EWSMTwoLoopEW.cpp.
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private |
The auxiliary function \({\cal V}_{fi}(q^2)\).
This function is used in DeltaEtaf1(). See [Degrassi:1990ec].
[in] | I3f | the isospin of a final-state fermion |
[in] | Qf | the electric charge of a final-state fermion |
[in] | q2 | invariant mass squared |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 566 of file EWSMTwoLoopEW.cpp.
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A reference to an object of type EWSMcache.
Definition at line 207 of file EWSMTwoLoopEW.h.
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An object of type EWSMOneLoopEW.
Definition at line 208 of file EWSMTwoLoopEW.h.