A class for \(O(\alpha\alpha_s)\) two-loop corrections to the EW precision observables. More...
#include <EWSMTwoLoopQCD.h>
A class for \(O(\alpha\alpha_s)\) two-loop corrections to the EW precision observables.
This class handles two-loop QCD contributions of \(O(\alpha\alpha_s)\) to the following quantities, which are relevant to the EW precision observables:
See also the description of EWSM class for their definitions. The above quantities are computed with the auxiliary functions:
and
The \(O(\alpha\alpha_s)\) two-loop QCD contributions to the vacuum polarization amplitudes of the gauge bosons were calculated in [Djouadi:1987gn], [Djouadi:1987di], [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu], [Kniehl:1992dx] and [Djouadi:1993ss].
Definition at line 55 of file EWSMTwoLoopQCD.h.
Public Member Functions | |
double | A1 (const double r) const |
The function \(A_1(r)\). More... | |
double | A1prime (const double r) const |
The derivative of the function \(A_1(r)\). More... | |
double | DeltaAlpha_l (const double s) const |
Leptonic contribution of \(O(\alpha\alpha_s)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{lept}}^{\alpha\alpha_s}(s)\). More... | |
double | DeltaAlpha_t (const double s) const |
Top-quark contribution of \(O(\alpha\alpha_s)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{top}}^{\alpha\alpha_s}(s)\). More... | |
gslpp::complex | deltaKappa_rem_f (const Particle f, const double Mw_i) const |
Remainder contribution of \(O(\alpha\alpha_s)\) to the effective couplings \(\kappa_Z^f\), denoted as \(\delta\kappa_{\mathrm{rem}}^{f,\, \alpha\alpha_s}\). More... | |
gslpp::complex | DeltaKappa_tb (const double Mw_i) const |
Heavy-quark contribution to \(\kappa_Z^f\), denoted as \(\Delta\kappa^{tb}\). More... | |
gslpp::complex | DeltaKappa_ud (const double Mw_i) const |
Light-quark contribution to \(\kappa_Z^f\), denoted as \(\Delta\kappa^{ud}\). More... | |
double | deltaQCD_2 () const |
The function \(\delta^{\mathrm{QCD}}_2\). More... | |
double | DeltaR_rem (const double Mw_i) const |
Remainder contribution of \(O(\alpha\alpha_s)\) to \(\Delta r\), denoted as \(\Delta r_{\mathrm{rem}}^{\alpha\alpha_s^2}\). More... | |
double | DeltaR_tb (const double Mw_i) const |
Heavy-quark contribution to \(\Delta r\), denoted as \(\Delta r^{tb}\). More... | |
double | DeltaR_ud (const double Mw_i) const |
Light-quark contribution to \(\Delta r\), not including \(\Delta\alpha^{l+5q}(M_Z^2)\), denoted as \(\Delta r^{ud}\). More... | |
double | DeltaRho (const double Mw_i) const |
Leading two-loop QCD contribution of \(O(\alpha\alpha_s)\) to \(\Delta\rho\), denoted as \(\Delta\rho^{\alpha\alpha_s}\). More... | |
gslpp::complex | deltaRho_rem_f (const Particle f, const double Mw_i) const |
Remainder contribution of \(O(\alpha\alpha_s)\) to the effective couplings \(\rho_Z^f\), denoted as \(\delta\rho_{\mathrm{rem}}^{f,\, \alpha\alpha_s}\). More... | |
double | DeltaRho_tb (const double Mw_i) const |
Heavy-quark contribution to \(\rho_Z^f\), denoted as \(\Delta\rho^{tb}\). More... | |
double | DeltaRho_ud (const double Mw_i) const |
Light-quark contribution to \(\rho_Z^f\), denoted as \(\Delta\rho^{ud}\). More... | |
EWSMTwoLoopQCD (const EWSMcache &cache_i) | |
Constructor. More... | |
double | F1 (const double x, const double Mw_i) const |
The function \(F_1(x)\). More... | |
double | V1 (const double r) const |
The function \(V_1(r)\). More... | |
double | V1prime (const double r) const |
The derivative of the function \(V_1(r)\). More... | |
Private Attributes | |
const EWSMcache & | cache |
A reference to an object of type EWSMcache. More... | |
EWSMTwoLoopQCD::EWSMTwoLoopQCD | ( | const EWSMcache & | cache_i | ) |
Constructor.
[in] | cache_i | a reference to an object of type EWSMcache |
Definition at line 12 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::A1 | ( | const double | r | ) | const |
The function \(A_1(r)\).
The expression for \(A_1(r)\) can be found in [Kniehl:1989yc] and [Halzen:1990je]. See also Chapter 8 of [Bardin:1999ak].
[in] | r | the ratio \(r=s/(4m_t^2)\) |
Definition at line 163 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::A1prime | ( | const double | r | ) | const |
The derivative of the function \(A_1(r)\).
The expression for \(A'_1(r)\) has been derived from \(A_1(r)\) in [Kniehl:1989yc] and [Halzen:1990je].
[in] | r | the ratio \(r=s/(4m_t^2)\) |
Definition at line 309 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaAlpha_l | ( | const double | s | ) | const |
Leptonic contribution of \(O(\alpha\alpha_s)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{lept}}^{\alpha\alpha_s}(s)\).
This contribution vanishes at \(O(\alpha\alpha_s)\).
[in] | s | invariant mass squared |
Definition at line 20 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaAlpha_t | ( | const double | s | ) | const |
Top-quark contribution of \(O(\alpha\alpha_s)\) to the electromagnetic coupling \(\alpha\), denoted as \(\Delta\alpha_{\mathrm{top}}^{\alpha\alpha_s}(s)\).
A simple numerical formula presented in [Kuhn:1998ze] has been employed.
[in] | s | invariant mass squared |
Definition at line 25 of file EWSMTwoLoopQCD.cpp.
gslpp::complex EWSMTwoLoopQCD::deltaKappa_rem_f | ( | const Particle | f, |
const double | Mw_i | ||
) | const |
Remainder contribution of \(O(\alpha\alpha_s)\) to the effective couplings \(\kappa_Z^f\), denoted as \(\delta\kappa_{\mathrm{rem}}^{f,\, \alpha\alpha_s}\).
The \(O(\alpha\alpha_s)\) remainder contribution to \(\kappa_{Z}^{f}\) is decomposed as
\[ \delta\kappa_{\mathrm{rem}}^{f,\,\alpha\alpha_s} = 2 \Delta\kappa^{ud} + \Delta\kappa^{tb} - \frac{c_W^2}{s_W^2}\Delta\rho^{\alpha\alpha_s}, \]
where \(\Delta\kappa^{ud}\) and \(\Delta\kappa^{tb}\) are associated with corrections to the self-energies of the gauge bosons with loops of a light-quark doublet and with those of the \(t\)- \(b\) doublet, respectively, and \((c_W^2/s_W^2)\Delta\rho^{\alpha\alpha_s}\) is the leading contribution of \(O(\alpha\alpha_s)\) to \(\kappa_{Z}^{f}\).
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 58 of file EWSMTwoLoopQCD.cpp.
gslpp::complex EWSMTwoLoopQCD::DeltaKappa_tb | ( | const double | Mw_i | ) | const |
Heavy-quark contribution to \(\kappa_Z^f\), denoted as \(\Delta\kappa^{tb}\).
The quantity \(\Delta\kappa^{tb}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the \(t\)- \(b\) doublet. The expression of \(\Delta\kappa^{tb}\) is given by
\[ \Delta\kappa^{tb} = \frac{\alpha\alpha_s(M_t^2)}{\pi^2} \frac{1}{4s_W^4} \Bigg\{ 4 c_W^2 w_t \Big[ v_t^2 V_1(r^Z_{4t}) + a_t^2A_1(r^Z_{4t}) - F_1(x^W_{t}) \Big] + 4s_W^2 \left( |Q_t| - 4s_W^2 Q_t^2 \right) z_t V_1(r^Z_{4t}) + \Big[ v_b^2 + a_b ^2 + s_W^2 \left( |Q_b| - 4s_W^2 Q_b^2 \right) \Big]\ln z_t \Bigg\} + i \frac{\alpha\alpha_s(M_Z^2)}{4\pi s_W^2} \left( \frac{1}{3} - \frac{4}{9}s_W^2 \right), \]
where the definitions of the symbols can be read from the codes below. See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 507 of file EWSMTwoLoopQCD.cpp.
gslpp::complex EWSMTwoLoopQCD::DeltaKappa_ud | ( | const double | Mw_i | ) | const |
Light-quark contribution to \(\kappa_Z^f\), denoted as \(\Delta\kappa^{ud}\).
The quantity \(\Delta\kappa^{ud}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the light-quark doublets. The expression of \(\Delta\kappa^{ud}\) is given by
\[ \Delta\kappa^{ud} = \frac{\alpha\alpha_s(M_Z^2)}{\pi^2} \frac{c_W^2}{4 s_W^4}\ln c_W^2 + i \frac{\alpha\alpha_s(M_Z^2)}{4\pi s_W^2} \left( 1 - \frac{20}{9}s_W^2 \right), \]
where the definitions of the symbols can be read from the codes below. See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 491 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::deltaQCD_2 | ( | ) | const |
The function \(\delta^{\mathrm{QCD}}_2\).
This function is associated with the leading two-loop QCD contribution of \(O(\alpha\alpha_s m_t^2/M_Z^2)\) to \(\Delta\rho\), as explained in the description of DeltaRho(). See [Kniehl:1989yc], [Halzen:1990je] and Chapter 8 of [Bardin:1999ak].
Definition at line 69 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaR_rem | ( | const double | Mw_i | ) | const |
Remainder contribution of \(O(\alpha\alpha_s)\) to \(\Delta r\), denoted as \(\Delta r_{\mathrm{rem}}^{\alpha\alpha_s^2}\).
The \(O(\alpha\alpha_s)\) remainder contribution to \(\Delta r\) is decomposed as
\[ \Delta r_{\mathrm{rem}}^{\alpha\alpha_s} = 2 \Delta r^{ud} + \Delta r^{tb} + \frac{c_W^2}{s_W^2} \Delta\rho^{\alpha\alpha_s}, \]
where \(\Delta r^{ud}\) and \(\Delta r^{tb}\) are associated with corrections to the self-energies of the gauge bosons with loops of a light-quark doublet and with those of the \(t\)- \(b\) doublet, respectively, and \(\Delta\rho^{\alpha\alpha_s}\) is the leading contribution.
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 44 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaR_tb | ( | const double | Mw_i | ) | const |
Heavy-quark contribution to \(\Delta r\), denoted as \(\Delta r^{tb}\).
The quantity \(\Delta r^{tb}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the \(t\)- \(b\) doublet. The expression of \(\Delta r^{tb}\) is given by
\[ \Delta r^{tb} = \frac{\alpha\alpha_s(M_t^2)}{\pi^2} \Bigg\{ Q_t^2 V_1'(0) + \frac{c_W^2}{s_W^4}\frac{w_t}{4}\left[ \zeta(2) + \frac{1}{2} \right] - \frac{z_t}{s_W^4} \Big[ v_t^2 V_1(r^Z_{4t}) + a_t^2\left[A_1(r^Z_{4t}) - A_1(0)\right] \Big] + \frac{c_W^2 - s_W^2}{s_W^4} w_t \Big[ F_1(x^W_{t}) - F_1(0) \Big] - \frac{v_ba_b}{2 s_W^4} \ln z_t \Bigg\}, \]
where the definitions of the symbols can be read from the codes below. See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 418 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaR_ud | ( | const double | Mw_i | ) | const |
Light-quark contribution to \(\Delta r\), not including \(\Delta\alpha^{l+5q}(M_Z^2)\), denoted as \(\Delta r^{ud}\).
The quantity \(\Delta r^{ud}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the light-quark doublets. The expression of \(\Delta r^{ud}\) is given by
\[ \Delta r^{ud} = - \frac{\alpha\alpha_s(M_Z^2)}{\pi^2}\frac{c_W^2 - s_W^2}{4s_W^4}\,\ln c_W^2. \]
See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 402 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaRho | ( | const double | Mw_i | ) | const |
Leading two-loop QCD contribution of \(O(\alpha\alpha_s)\) to \(\Delta\rho\), denoted as \(\Delta\rho^{\alpha\alpha_s}\).
The formula used here is given by
\[ \Delta\rho^{\alpha\alpha_s} = 3\,X_t^\alpha\frac{\alpha_s(m_t^2)}{\pi} \delta^{\mathrm{QCD}}_2, \]
where \(X_t^\alpha = \alpha\, m_t^2/(16\pi s_W^2 M_W^2)\), and \(\delta^{\mathrm{QCD}}_2\) is computed via deltaQCD_2(). See, e.g., Chapter 8 of [Bardin:1999ak]. This quantity contributes to \(\Delta r\) and the \(Zf\bar{f}\) effective couplings \(\rho_Z^f\) and \(\kappa_Z^f\). See also the description of EWSM class.
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 38 of file EWSMTwoLoopQCD.cpp.
gslpp::complex EWSMTwoLoopQCD::deltaRho_rem_f | ( | const Particle | f, |
const double | Mw_i | ||
) | const |
Remainder contribution of \(O(\alpha\alpha_s)\) to the effective couplings \(\rho_Z^f\), denoted as \(\delta\rho_{\mathrm{rem}}^{f,\, \alpha\alpha_s}\).
The \(O(\alpha\alpha_s)\) remainder contribution to \(\rho_{Z}^{f}\) is decomposed as
\[ \delta\rho_{\mathrm{rem}}^{f,\,\alpha\alpha_s} = 2 \Delta\rho^{ud} + \Delta\rho^{tb} - \Delta\rho^{\alpha\alpha_s}, \]
where \(\Delta\rho^{ud}\) and \(\Delta\rho^{tb}\) are associated with corrections to the self-energies of the gauge bosons with loops of a light-quark doublet and with those of the \(t\)- \(b\) doublet, respectively, and \(\Delta\rho^{\alpha\alpha_s}\) is the leading contribution of \(O(\alpha\alpha_s)\) to \(\rho_{Z}^{f}\).
[in] | f | a lepton or quark |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 51 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaRho_tb | ( | const double | Mw_i | ) | const |
Heavy-quark contribution to \(\rho_Z^f\), denoted as \(\Delta\rho^{tb}\).
The quantity \(\Delta\rho^{tb}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the \(t\)- \(b\) doublet. The expression of \(\Delta\rho^{tb}\) is given by
\[ \Delta\rho^{tb} = \frac{\alpha\alpha_s(M_t^2)}{\pi^2} \frac{1}{4s_W^2 c_W^2} \Big\{ - \left[ v_t^2 V_1'(r^Z_{4t}) + a_t^2 A_1'(r^Z_{4t}) \right] + 4 z_t \left[ v_t^2 V_1(r^Z_{4t}) + a_t^2 A_1(r^Z_{4t}) \right] + v_b^2 + a_b^2 - 4 z_t\, F_1(0) \Big\}, \]
where the definitions of the symbols can be read from the codes below. See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 467 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::DeltaRho_ud | ( | const double | Mw_i | ) | const |
Light-quark contribution to \(\rho_Z^f\), denoted as \(\Delta\rho^{ud}\).
The quantity \(\Delta\rho^{ud}\) is associated with \(O(\alpha\alpha_s)\) corrections to the self-energies of the gauge bosons with loops of the light-quark doublets. The expression of \(\Delta\rho^{ud}\) is given by
\[ \Delta\rho^{ud} = \frac{\alpha\alpha_s(M_Z^2)}{\pi^2} \frac{1}{4s_W^2 c_W^2} \left( v_u^2 + v_d^2 + a_u^2 + a_d^2 \right), \]
where the definitions of the symbols can be read from the codes below. See [Kniehl:1989yc], [Halzen:1990je], [Kniehl:1991gu] and Chapter 8 of [Bardin:1999ak].
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 451 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::F1 | ( | const double | x, |
const double | Mw_i | ||
) | const |
The function \(F_1(x)\).
The expression for \(F_1(x)\) can be found in [Kniehl:1989yc] and [Halzen:1990je]. See also Chapter 8 of [Bardin:1999ak].
[in] | x | the ratio \(x=s/m_t^2\) |
[in] | Mw_i | the \(W\)-boson mass |
Definition at line 74 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::V1 | ( | const double | r | ) | const |
The function \(V_1(r)\).
The expression for \(V_1(r)\) can be found in [Kniehl:1989yc] and [Halzen:1990je]. See also Chapter 8 of [Bardin:1999ak].
[in] | r | the ratio \(r=s/(4m_t^2)\) |
Definition at line 111 of file EWSMTwoLoopQCD.cpp.
double EWSMTwoLoopQCD::V1prime | ( | const double | r | ) | const |
The derivative of the function \(V_1(r)\).
The expression for \(V'_1(r)\) has been derived from \(V_1(r)\) in [Kniehl:1989yc] and [Halzen:1990je].
[in] | r | the ratio \(r=s/(4m_t^2)\) |
Definition at line 216 of file EWSMTwoLoopQCD.cpp.
|
private |
A reference to an object of type EWSMcache.
Definition at line 376 of file EWSMTwoLoopQCD.h.