TTP09-46 Precise Charm- and Bottom-Quark Masses: Recent Developments

TTP09-46 Precise Charm- and Bottom-Quark Masses: Recent Developments

Recent theoretical and experimental improvements in the determination of charm- and bottom-quark masses are discussed. The final results, m_c(3 GeV)=986(13) MeV and m_b(m_b)=4163(16) MeV represent the presently most precise determinations of these two fundamental Standard Model parameters.

 J. H. Kühn FLAVIAnet Topical Workshop Kazimierz, Poland, 23-27 July 2009. To be published in the proceedings PDF PostScript
TTP09-45 Two-loop SUSY-QCD corrections to h→b anti-b
L. Mihaila and C. Rei&szlig;er
PDF PostScript

TTP09-44 Three-loop static potential

TTP09-44 Three-loop static potential

We compute the three-loop corrections to the potential of two heavy quarks. In particular we consider in this Letter the purely gluonic contribution which provides in combination with the fermion corrections of Ref. \cite{Smirnov:2008pn} the complete answer at three loops.

 A.V. Smirnov, V.A. Smirnov, M. Steinhauser Phys.Rev.Lett. 104 112002 2010 PDF PostScript arXiv

TTP09-43 Finite top quark mass effects in NNLO Higgs boson production at LHC

TTP09-43 Finite top quark mass effects in NNLO Higgs boson production at LHC

We present next-to-next-to-leading order corrections to the inclusive production of the Higgs bosons at the CERN Large Hadron Collider (LHC) including finite top quark mass effects. Expanding our analytic results for the partonic cross section around the soft limit we find agreement with a very recent publication by Harlander and Ozeren \cite{Harlander:2009mq}.

 Alexey Pak, Mikhail Rogal, Matthias Steinhauser JHEP 1002 025 2010 PDF PostScript arXiv

TTP09-42 Power suppressed effects in B -&gt; X_s gamma at O(alpha_s)

TTP09-42 Power suppressed effects in B -&gt; X_s gamma at O(alpha_s)

We compute the O(alpha_s) corrections to the Wilson coefficients of the dimension five operators emerging from the Operator Product Expansion of inclusive radiative B decays. We discuss the impact of the resulting O(alpha_s Lambda_QCD^2/m_b^2) corrections on the extraction of m_b and mu_pi^2 from the moments of the photon spectrum.

 Thorsten Ewerth, Paolo Gambino, Soumitra Nandi Nucl.Phys. B830 278-290 2010 PDF PostScript arXiv

TTP09-41 Matching QCD and HQET heavy–light currents at three loops

TTP09-41 Matching QCD and HQET heavy–light currents at three loops

We consider the currents formed by a heavy and a light quark within Quantum Chromodynamics and compute the matching to Heavy Quark Effective Theory to three-loop accuracy. As an application we obtain the third-order perturbative corrections to ratios of $B$-meson decay constants.

 S. Bekavac, A.G. Grozin, P. Marquard, J.H. Piclum, D. Seidel, M. Steinhauser Nucl.Phys.B833:46-63 B833 46-63 2010 PDF PostScript arXiv Programs and Data

TTP09-40 Wilson Expansion of QCD propagators at Three Loops: Operators of Dimension Two and Three

TTP09-40 Wilson Expansion of QCD propagators at Three Loops: Operators of Dimension Two and Three

In this paper we construct the Wilson short distance operator product expansion for the gluon, quark and ghost propagators in QCD, including operators of dimension two and three, namely, A^2, m^2, m A^2, \ovl{\psi} \psi and m^3. We compute analytically the coefficient functions of these operators at three loops for all three propagators in the general covariant gauge. Our results, taken in the Landau gauge, should help to improve the accuracy of extracting the vacuum expectation values of these operators from lattice simulation of the QCD propagators.

 K.G. Chetyrkin, A. Maier JHEP 01 092 2010 PDF PostScript arXiv Programs and Data

TTP09-39 Current status of FORM parallelization

TTP09-39 Current status of FORM parallelization

The program FIESTA has been completely rewritten. Now it can be used not only as a tool to evaluate Feynman integrals numerically, but also to expand Feynman integrals automatically in limits of momenta and masses with the use of sector decompositions and Mellin-Barnes representations. Other important improvements to the code are complete parallelization (even to multiple computers), high-precision arithmetics (allowing to calculate integrals which were undoable before), new integrators and Speer sectors as a strategy, the possibility to evaluate more general parametric integrals.

 A.V. Smirnov, V.A. Smirnov, M. Tentyukov Comput.Phys.Commun. 182 790-803 2011 PDF PostScript arXiv

TTP09-38 Lepton flavour violation in the MSSM

TTP09-38 Lepton flavour violation in the MSSM

We derive new constraints on the quantities delta_{XY}^{ij, X,Y=L,R, which parametrise the flavour-off-diagonal terms of the charged slepton mass matrix in the MSSM. Considering mass and anomalous magnetic moment of the electron we obtain the bound delta^{13}_{LL}*delta^{13}_{RR} < 0.1, which involves the poorly constrained element delta^{13}_{RR}. We improve the predictions for the decays tau → mu gamma, tau → e gamma and mu → e gamma by including two-loop corrections which are enhanced if tan beta is large. The finite renormalisation of the PMNS matrix from soft SUSY-breaking terms is derived and applied to the charged-Higgs-lepton vertex. We find that the experimental bound on BR(tau → e gamma) severely limits the size of the MSSM loop correction to the PMNS element U_{e3}, which is important for the proper interpretation of a future U_{e3} measurement. Subsequently we confront our new values for delta^{ij}_{LL} with a GUT analysis. As a novel feature we consider dimension-5 Yukawa terms, which are needed to fix the Yukawa unification of the first two generations. If universal supersymmetry breaking occurs above the GUT scale, we find the flavour structure of the dimension-5 Yukawa couplings tightly constrained by mu → e gamma.

 Jennifer Girrbach, Susanne Mertens, Ulrich Nierste, Söoren Wiesenfeldt PDF PostScript

TTP09-37 Grand Unified Flavour Physics

TTP09-37 Grand Unified Flavour Physics

We probe the unification of down quarks and leptons in a supersymmetric $\text{SO}(10)$ GUT. The large atmospheric neutrino mixing angle induces $b_R-s_R$ transitions, which can account for the sizeable $CP$ phase $\phi_s$ measured in $B_s-\ovl{B}_s$ mixing. Corrections to down-quark-lepton unification from higher-dimensional Yukawa terms translate neutrino mixing also into $s_R-d_R$ and $b_R-d_R$ currents. We find the flavour structure of Yukawa corrections to be strongly constrained by $\epsilon_K$.

 Susanne Westhoff AIP Conf.Proc. 1200 572-575 2010 PDF PostScript arXiv

TTP09-36 The MSSM with large tan(beta) beyond the decoupling limit

TTP09-36 The MSSM with large tan(beta) beyond the decoupling limit

For large values of tan(beta) interesting effects arise in the MSSM due to the enhancement of down-quark self-energies. These effects are well-studied within the decoupling limit, i.e. in the limit of supersymmetric masses far above the electroweak scale. In this article I discuss those issues which emerge from a treatment of these effects that goes beyond the decoupling limit.

 Lars Hofer FLAVIAnet Topical Workshop Kazimierz, Poland, 23-27 July 2009. To be published in the proceedings. PDF PostScript arXiv

TTP09-35 Search for New Physics in Electroweak Penguins via B_s Decays

TTP09-35 Search for New Physics in Electroweak Penguins via B_s Decays

The discrepancies found in the B-&gt;pi K decays between theory and experiment suggest the presence of new physics in the electroweak penguin sector of the theory. We show that this hypothesis can be tested more efficiently including in the analysis the non-leptonic decays B_s-&gt;phi pi, B_s-&gt;phi rho.

 Lars Hofer, Dominik Scherer, Leonardo Vernazza Acta Phys.Polon. B3 227-233 2010 PDF PostScript arXiv

TTP09-34 Quark masses from low-energy moments of heavy-quark current correlators

TTP09-34 Quark masses from low-energy moments of heavy-quark current correlators

We present an update of the determination of charm- and

       bottom-quark masses from the low-energy expansion of the vacuum
polarization function in combination with experimental data for
R(s). This analysis leads to the most precise determination of
the masses of the charm and bottom quarks:
m_c(3GeV) = 986(13)MeV, m_b(m_b) =
4163(16)MeV.
 P. Marquard PDF PostScript

TTP09-33 Gluinonia: Energy Levels, Production and Decay

TTP09-33 Gluinonia: Energy Levels, Production and Decay

Predictions for energy levels, production and decay rate of gluinonia, non-relativistic boundstates of gluinos, are presented. The potential between color-octet constituents is derived in next-to-next-to leading order and one-loop QCD corrections are derived for the production cross section and the decay rate into gluon jets. In addition we evaluate the decay rate into top quarks and into two photons. The signal-to-background ratio is estimated for the dominant decay mode and found to be around 0.5%. For relatively light gluinos the bound states thus might be detectable.

 Matthias R. Kauth, Johann H. K\“uhn, Peter Marquard, Matthias Steinhauser Nucl.Phys.B 831 285-305 2010 PDF PostScript arXiv
TTP09-32 NNLL Electroweak Corrections to Gauge Boson Pair Production at LHC
Sandro Uccirati
PoS EPS-HEP2009 (2009) 345
PDF PostScript

TTP09-31 Gluino-mediated FCNCs in the MSSM with large tan(beta)

TTP09-31 Gluino-mediated FCNCs in the MSSM with large tan(beta)

We present results of our study of tan(beta)-enhanced loop corrections in the Minimal Supersymmetric Standard Model (MSSM) with Minimal Flavour Violation (MFV). We demonstrate that these corrections induce flavour changing neutral current (FCNC) gluino couplings which have a large impact on the Wilson coefficient C_8 of the chromomagnetic operator. To illustrate the phenomenological consequences of this gluino-squark contribution to C_8, we briefly discuss its effect on the mixing-induced CP asymmetry in the decay B_d -&gt; phi K_S.

 Lars Hofer, Ulrich Nierste, Dominik Scherer PoS EPS-HEP 2009 181 2009 PDF PostScript arXiv

TTP09-30 Weak effects in b-jet production at hadron colliders

TTP09-30 Weak effects in b-jet production at hadron colliders

One of the main challenges of the Tevatron at Fermilab and the Large Hadron Collider (LHC) at CERN is the determination of Standard Model (SM) parameters at the TeV scale. In this context various processes will be investigated which involve bottom-quark jets in the final state, for example decays of top-quarks or gauge bosons of the weak interaction. Hence the theoretical understanding of processes with bottom-quark jets is necessary. In this paper analytic results will be presented for the weak corrections to bottom-quark jet production – neglecting purely photonic corrections. The results will be used to study differential distributions, where sizeable effects are observed.

 J.H. K\“uhn, A. Scharf, P. Uwer Phys.Rev. D82 013007 2010 PDF PostScript arXiv

TTP09-29 Two-loop parameter relations between dimensional regularization and dimensional reduction applied to SUSY-QCD

TTP09-29 Two-loop parameter relations between dimensional regularization and dimensional reduction applied to SUSY-QCD

The two-loop relations between the running gluino-quark-squark coupling, the gluino and the quark mass defined in dimensional regularization (DREG) and dimensional reduction (DRED) in the framework of SUSY-QCD are presented. Furthermore, we verify with the help of these relations that the three-loop beta-functions derived in the minimal subtraction scheme combined with DREG or DRED transform into each other. This result confirms the equivalence of the two schemes through three-loops, if applied to SUSY-QCD.

 Luminita Mihaila Phys.Lett. B681 52-59 2009 PDF PostScript arXiv

TTP09-28 Chirally enhanced corrections to FCNC processes in the generic MSSM

TTP09-28 Chirally enhanced corrections to FCNC processes in the generic MSSM

Chirally enhanced supersymmetric QCD corrections to FCNC processes are investigated in the framework of the MSSM with generic sources of flavor violation. These corrections arise from flavor-changing self-energy diagrams and can be absorbed into a finite renormalization of the squark-quark-gluino vertex. In this way enhanced two-loop and even three-loop diagrams can be efficiently included into a leading-order (LO) calculation. Our corrections substantially change the values of the parameters delta^{d,LL}_{23}, delta^{d,LR}_{23}, delta^{d,RL}_{23}, and delta^{d,RR}_{23} extracted from Br[B-&gt;X_s gamma] if tan(beta) is large. We find stronger (weaker) constraints compared to the LO result for negative (positive) values of mu. The constraints on delta^{d,LR,RL}_{13} and delta^{d,LR,RL}_{23} from B_d mixing and B_s mixing change drastically if the third-generation squark masses differ from those of the first two generations. K mixing is more strongly affected by the chirally enhanced loop diagrams and even sub-percent deviations from degenerate down and strange squark masses lead to profoundly stronger constraints on delta^{d,LR,RL}_{12}.

 Andreas Crivellin and Ulrich Nierste Phys.Rev. D81 095007 2010 PDF PostScript arXiv

TTP09-27 Tree-level contributions to the rare B+ –

TTP09-27 Tree-level contributions to the rare B+ –

X+ nu nu bar decays in the Standard Model > The tree-level contributions to the rare decays B+ –> pi+ nu anti-nu, B+ –> K+ nu anti-nu, and B+ –> K*+ nu anti-nu are analyzed and compared to those occurring in K+ –> pi+ nu anti-nu, D+ –> pi+ nu anti-nu, and Ds+ –> pi+ nu anti-nu. It is shown that these purely long-distance contributions, arising from the exchange of a charged lepton, can be significant in B+ decays for an intermediate tau, potentially blurring the distinction between the modes used to extract B –> tau nu and those used to probe the genuine short-distance b –> (s,d) nu anti-nu FCNC transitions. Numerically, the tree-level contributions are found to account for 97%, 12% and 14% of the total B+ –> pi+ nu anti-nu, B+ –> K+ nu anti-nu, and B+ –> K*+ nu anti-nu rates, respectively.

 Jernej F. Kamenik and Christopher Smith Phys.Lett. B680 471-475 2009 PDF PostScript arXiv

TTP09-26 Resummation of tan-beta-enhanced supersymmetric loop corrections beyond the decoupling limit

TTP09-26 Resummation of tan-beta-enhanced supersymmetric loop corrections beyond the decoupling limit

We study the Minimal Supersymmetric Standard Model with Minimal

 Flavour Violation for the case of a large parameter tan beta and
arbitrary values of the supersymmetric mass parameters. We derive
several resummation formulae for tan-beta-enhanced loop
corrections, which were previously only known in the limit of
supersymmetric masses far above the electroweak scale. Studying first
the renormalisation-scheme dependence of the resummation formula for
the bottom Yukawa coupling, we clarify the use of the sbottom mixing
angle in the supersymmetric loop factor Delta_b. As a new feature,
we find tan-beta-enhanced loop-induced flavour-changing neutral
current (FCNC) couplings of gluinos and neutralinos which in turn give
rise to new effects in the renormalisation of the
Cabibbo-Kobayashi-Maskawa matrix and in FCNC processes of B mesons.
For the chromomagnetic Wilson coefficient C8, these gluino-squark
loops can be of the same size as the known chargino-squark
contribution. We discuss the phenomenological consequences for the
mixing-induced CP asymmetry in B_d -> phi K_S. We further quote
formulae for B_s -> mu mu and B <-> anti-B mixing valid beyond the
decoupling limit and find a new contribution affecting the phase of
the B <-> anti-B mixing amplitude. Our resummed tan-beta-enhanced effects are
cast into Feynman rules permitting an easy implementation in automatic
calculations.
 Lars Hofer, Ulrich Nierste and Dominik Scherer JHEP 0910 081 2009 PDF PostScript arXiv

TTP09-25 NNLO corrections to charmless hadronic B decays

TTP09-25 NNLO corrections to charmless hadronic B decays

We report on the status of the perturbative calculation in the QCD factorization framework to charmless hadronic $B$ meson decays and present a compilation of available NNLO results.

 Guido Bell To appear in the proceedings of International Workshop on Effective Field Theories: From the Pion to the Upsilon (EFT 09), Valencia, Spain, 2-6 Feb 2009 PDF PostScript arXiv

TTP09-24 Effects of right-handed charged currents on the determinations of |V_{ub}| and |V_{cb}|

TTP09-24 Effects of right-handed charged currents on the determinations of |V_{ub}| and |V_{cb}|

We study the effect of a right-handed coupling of quarks to the

 W-boson on the measurements of |V_{ub}| and |V_{cb }|. It is shown that
such a coupling can remove the discrepancies between the
determinations of |V_{ub}| from B\to \pi \ell \nu, B^+\to \tau^+
\nu and B\to X_u \ell \nu.  Further the measurements of |V_{cb}|
from B\to D^* \ell \nu, B\to D \ell \nu and inclusive B\to X_c
\ell\nu decays can be brought into better agreement.  We demonstrate
that a right-handed coupling can be generated within the MSSM by a
finite gluino-squark loop. The effect involves the parameters
\delta^{u RL}_{23} and \delta^{u RL}_{13} of the squark mass
matrices, which are poorly constrained from other processes. On the
other hand, all gluino-squark corrections to the regular left-handed
coupling of the W-boson are found to be too small to be relevant.
 Andreas Crivellin Phys.Rev. D81 031301 2010 PDF PostScript arXiv

TTP09-23 Virtual three-loop corrections to Higgs boson production in gluon fusion for finite top quark mass

TTP09-23 Virtual three-loop corrections to Higgs boson production in gluon fusion for finite top quark mass

In this letter we present the three-loop virtual corrections to the Higgs boson production in the gluon fusion channel where finite top quark mass effects are taken into account. We perform an asymptotic expansion and manage to evaluate five terms in the expansion parameter $M_H^2/M_t^2$. A good convergence is observed almost until $M_H\approx 2M_t$.

 Alexey Pak, Mikhail Rogal, Matthias Steinhauser Phys.Lett. B679 473-477 2009 PDF PostScript arXiv Programs and Data

TTP09-22 B- -

TTP09-22 B- -

pi- pi0 / rho- rho0 to NNLO in QCD factorization > The approximate tree decays B- → pi- pi0/rho- rho0 may serve as benchmark channels for testing the various theoretical descriptions of the strong interaction dynamics in hadronic B meson decays. The ratios of hadronic and differential semileptonic B → pi l nu/rho l nu decay rates at maximum recoil provide particularly clean probes of the QCD dynamics. We confront the recent NNLO calculation in the QCD factorization framework with experimental data and find support for the factorization assumption. A detailed analysis of all tree-dominated B → pi pi/pi rho/rho rho decay modes seems to favour somewhat enhanced colour-suppressed amplitudes, which may be accommodated in QCD factorization by a small value of the first inverse moment of the B meson light-cone distribution amplitude, lambda_B ~ 250 MeV. Precise measurements of the B → rho l nu spectrum could help to clarify this point.

 Guido Bell and Volker Pilipp Phys.Rev. D80 054024 2009 PDF PostScript arXiv

TTP09-21 Introduction to effective field theories. 1. Heisenberg-Euler effective theory, decoupling of heavy flavours

TTP09-21 Introduction to effective field theories. 1. Heisenberg-Euler effective theory, decoupling of heavy flavours

This is the first part of lectures about effective field theories. Decoupling of heavy-particle loops is considered (heavy leptons in QED, heavy quarks in QCD).

 Andrey Grozin Lectures given at Conference PDF PostScript arXiv

TTP09-20 Supersymmetric Corrections to the Threshold Production of Top Quark Pairs

TTP09-20 Supersymmetric Corrections to the Threshold Production of Top Quark Pairs

In this paper we investigate supersymmetric effects to the threshold production cross section of top quark pairs in electron positron annihilation. In particular, we consider the complete one-loop corrections from the strong and weak sector of the Minimal Supersymmetric Standard Model.

 Y. Kiyo, M. Steinhauser, N. Zerf Phys.Rev. D80 075005 2009 PDF PostScript arXiv Programs and Data

TTP09-19 R(s) and hadronic tau-Decays in Order alpha_s^4: technical aspects

TTP09-19 R(s) and hadronic tau-Decays in Order alpha_s^4: technical aspects

We report on some technical aspects of our calculation of alpha_s^4 corrections to R(s) and the semi-leptonic tau decay width [1-3]. We discuss the inner structure of the result as well as the issue of its correctness. We demonstrate recently appeared independent evidence positively testing one of two components of the full result.

 P.A. Baikov, K.G. Chetyrkin and J.H. K\“uhn… Nucl.Phys.Proc.Suppl. 189 189 49-53 2009 PDF PostScript arXiv

TTP09-18 Low energy moments of heavy quark current correlators at four loops

TTP09-18 Low energy moments of heavy quark current correlators at four loops

We describe several techniques for the calculation of multi-loop integrals and their application to heavy quark current correlators. As new results, we present the four-loop correction to the second and third physical moment in the low-energy expansions of vector, axial-vector and scalar quark current correlators. Using a Ward identity, we obtain the third and fourth moment for the pseudo-scalar correlator. We briefly discuss the impact of these results on the determination of the charm quark mass and the strong coupling constant using lattice simulations for the current correlators and of the charm- and bottom-quark mass from experimental data for &sigma;(e+ e- &rarr; hadrons).

 A. Maier, P. Maierhöfer, P. Marquard, A.V. Smirnov Nuclear Physics B 824 1-18 2010 PDF PostScript arXiv Programs and Data

TTP09-17 Reconstruction of heavy quark current correlators at O(&alpha;<sub

TTP09-17 Reconstruction of heavy quark current correlators at O(&alpha;<sub

s</sub>3) > We construct approximate formulas for the O(&alpha;s3) QCD contributions to vector, axial-vector, scalar and pseudo-scalar quark current correlators, which are valid for arbitrary values of momenta and masses. The derivation is based on conformal mapping and the Pad&eacute; approximation procedure and incorporates known expansions in the low energy, threshold and high energy regions. We use our results to estimate additional terms in these expansions.

 Y. Kiyo, A. Maier, P. Maierhöfer, P. Marquard Nuclear Physics B 823 269-287 2009 PDF PostScript arXiv Programs and Data

TTP09-16 Charm and Bottom Quark Masses: an Update

TTP09-16 Charm and Bottom Quark Masses: an Update

Using new four-loop results for the heavy quark vacuum polarization and new data for bottom quark production in electron-positron annihilation, an update on the determination of charm- and bottom-quark masses through sum rules has been performed. The previous result for the charm-quark mass, $m_c(3 {\rm GeV})= 0.986(13) {\rm GeV}$, based on the lowest moment, is supported by the new results from higher moments which lead to consistent values with comparable errors. The new value for the bottom quark, $m_b(10 {\rm GeV})= 3.610(16) {\rm GeV}$, corresponding to $m_b(m_b)= 4.163(16) {\rm GeV}$, makes use both of the new data and the new perturbative results and is consistent with the earlier determination.

 K. G. Chetyrkin, J. H. Kühn, A. Maier, P. Maierhöfer, P. Marquard, M. Steinhauser, C. Sturm Phys.Rev. D80 074010 2009 PDF PostScript arXiv

TTP09-15 Light quark mass effects in the chromomagnetic moment

TTP09-15 Light quark mass effects in the chromomagnetic moment

We present the three-loop QCD corrections to the quark chromomagnetic moment including two different nonzero masses. This is a necessary ingredient to obtain the corresponding corrections to the chromomagnetic coefficient in the Heavy Quark Effective Theory (HQET) Lagrangian.

 S. Bekavac, A. Grozin, D. Seidel, M. Steinhauser PDF PostScript arXiv

TTP09-14 CKM ELEMENTS FROM SQUARK-GLUINO LOOPS

TTP09-14 CKM ELEMENTS FROM SQUARK-GLUINO LOOPS

I present results for the finite renormalization of the Cabibbo-Kobayashi-Maskawa ( CKM)

matrix induced by gluino--squark diagrams in the MSSM with non-minimal
sources of flavour violation. Subsequently I derive bounds on the
flavour--off--diagonal elements of the squark mass matrices by requiring that the

 the CKM elements do not exceed the experimental values. The constraints on
the associated dimensionless quantities $\delta^{d\,LR}_{ij}$, $j&gt;i$, are
stronger than the bounds from flavour-changing neutral current (FCNC)
processes if gluino and squarks are heavier than 500$\,\gev$. The
results imply that it is still possible to generate all observed flavour
violation from the soft supersymmetry-breaking terms without conflicting
with present-day data on FCNC processes. Therefore we reappraise the idea that onl

y $Y^q_{33}$

 is different from zero at tree-level and all other Yukawa couplings are generated

radiatively. This model solves the SUSY flavour as well as the SUSY CP problem. The presented results are published in \cite{Crivellin:2008mq}.

 Andreas Crivellin To appear in the proceedings of 44th Rencontres de Moriond EW 2009: Electroweak Interactions and Unified Theories, La Thuile, Italy, 7-14 Mar 2009. PDF PostScript arXiv

TTP09-13 The SUSY-QCD beta-function to three loops

TTP09-13 The SUSY-QCD beta-function to three loops

A number of $\drbar$ renormalization constants in softly broken \susy{}-\qcd{} are evaluated to three-loop level: the wave function renormalization constants for quarks, squarks, gluons, gluinos, ghosts, and \epscalar{}s, and the renormalization constants for the quark and

 gluino mass as well as for all cubic vertices. The latter allow us to

derive the corresponding $\beta$ functions through three loops, all of which we find to be identical to the expression for the gauge $\beta$ function obtained by Jack, Jones, and North~\cite{Jack:1996vg} (see also Ref.\,\cite{Pickering:2001aq}). This explicitely demonstrates the consistency of \dred{} with \susy{} and gauge invariance, an important pre-requisite for precision calculations in supersymmetric theories.

 Robert Harlander, Luminita Mihaila, Matthias Steinhauser Eur.Phys.J. C63 383-390 2009 PDF PostScript arXiv Programs and Data

TTP09-12 Four-pion production in tau decays and e+e- annihilation: an update

TTP09-12 Four-pion production in tau decays and e+e- annihilation: an update

An improved description of four-pion production in electron-positron annihilation and in tau lepton decays is presented. The model amplitude is fitted to recent data from BaBar which cover a wide energy range and which were obtained exploiting the radiative return. Predicting tau decay distributions from e+e- data and comparing these predictions with ALEPH and CLEO results, the validity of isospin symmetry is confirmed within the present experimental errors. A good description of two- and three-pion sub-distributions is obtained. Special emphasis is put on the predictions for omega pi (→ pi+pi-pi0) in e+e- annihilation and in tau decay. The model amplitude is implemented in the Monte Carlo generator PHOKHARA.

 Henryk Czyz, Johann H. Kuhn, Agnieszka Wapienik Phys.Rev. D77 114005 2008 PDF PostScript arXiv

TTP09-11 Strong and Electromagnetic J/psi and psi(2S) decays into Kaon and Pion Pairs

TTP09-11 Strong and Electromagnetic J/psi and psi(2S) decays into Kaon and Pion Pairs

A combined analysis of the electromagnetic pion and kaon form factors in the neighborhood of J/psi and psi(2S) and of the strong decay amplitude of these resonances into kaons is presented. In the presence of a large relative phase between strong and electromagnetic resonance amplitudes the branching ratio, as measured in electron-positron annihilation, receives an additional contribution from the interference between resonance and continuum amplitude neglected in earlier papers. Our study is model independent and does not rely on the SU(3) symmetry assumptions used in earlier papers. We note that the large relative phase between strong and electromagnetic amplitudes observed in earlier analyses is model dependent and relies critically on the specific assumptions on SU(3) symmetry and breaking.

 Henryk Czyz, Johann H. K\“uhn Phys.Rev. D80 034035 2009 PDF PostScript arXiv

TTP09-10 Probing Yukawa Unification with K and B mixing

TTP09-10 Probing Yukawa Unification with K and B mixing

We consider corrections to the unification of down-quark and charged-lepton Yukawa couplings in supersymmetric GUTs, which links the large nu_tau-nu_mu mixing angle to b → s transitions. These corrections generically occur in simple grand-unified models with small Higgs representations and affect s → d and b → d transitions via the mixing of the corresponding right-handed superpartners. On the basis of a specific SUSY-SO(10) model, we analyze the constraints from K-Kbar and B-Bbar mixing on the additional \tilde{d}_R-\tilde{s}_R rotation angle theta. We find that epsilon_K already sets a stringent bound on theta, theta^{max}=O(1 degree), indicating a very specific flavor structure of the correction operators. The impact of the large neutrino mixings on the unitarity triangle analysis is also briefly discussed, as well as their ability to account for the sizeable CP-violating phase observed recently in B_s → psi phi decays.

 Stephanie Trine, Susanne Westhoff, and Sören Wiesenfeldt JHEP 0908 002 2009 PDF PostScript arXiv

TTP09-09 Completely automated computation of the heavy-fermion corrections to the three-loop matching coefficient of the vector current

TTP09-09 Completely automated computation of the heavy-fermion corrections to the three-loop matching coefficient of the vector current

We evaluate the corrections to the matching coefficient of the vector current between Quantum Chromodynamics (QCD) and Non-Relativistic QCD (NRQCD) to three-loop order containing a closed heavy-fermion loop. The result constitutes a building block both for the bottom- and top-quark system at threshold. Strong emphasis is put on our completely automated approach of the calculation including the generation of the Feynman diagrams, the identification of the topologies, the reduction to master integrals and the automated numerical computation of the latter.

 P. Marquard, J.H. Piclum, D. Seidel, M. Steinhauser Phys.Lett. B678 269-275 2009 PDF PostScript arXiv

TTP09-08 Three-loop on-shell Feynman integrals with two masses

TTP09-08 Three-loop on-shell Feynman integrals with two masses

All three-loop on-shell QCD Feynman integrals with two masses can be reduced to 27 master integrals. Here we calculate these master integrals, expanded in epsilon, both exactly in the mass ratio and as series in limiting cases.

 S.Bekavac, A.G.Grozin, D.Seidel, V.A.Smirnov Nucl.Phys. B819 183-200 2009 PDF PostScript arXiv Programs and Data

TTP09-07 Three Lectures on Meson Mixing and CKM phenomenology

TTP09-07 Three Lectures on Meson Mixing and CKM phenomenology

I give an introduction to the theory of meson-antimeson mixing, aiming at students who plan to work at a flavour physics experiment or intend to do associated theoretical studies. I derive the formulae for the time evolution of a neutral meson system and show how the mass and width differences among the neutral meson eigenstates and the CP phase in mixing are calculated in the Standard Model. Special emphasis is laid on CP violation, which is covered in detail for \kkm, \bbmd\ and \bbms. I explain the constraints on the apex $(\ov \rho,\ov \eta)$ of the unitarity triangle implied by $\e_K$, $\dm_{B_d}$, $\dm_{B_d}/\dm_{B_s}$ and various mixing-induced CP asymmetries such as $a_{\rm CP} (\ov B_d \to J/\psi K_{\rm  short})(t)$.

The impact of a future measurement of CP violation in flavour-specific $B_d$ decays is also shown.

 Ulrich Nierste Lectures given at Helmholz International Summer School on Heavy Quark Physics, Dubna, Moscow Region, Russia, 11-21 Aug 2008. Published in *Dubna 2008, Heavy quark physics (HQP08)* 1-38 PDF PostScript arXiv

TTP09-06 Nine-Propagator Master Integrals for Massless Three-Loop Form Factors

TTP09-06 Nine-Propagator Master Integrals for Massless Three-Loop Form Factors

We complete the calculation of master integrals for massless three-loop form factors by computing the previously-unknown three diagrams with nine propagators in dimensional regularisation. Each of the integrals yields a six-fold Mellin-Barnes representation which we use to compute the coefficients of the Laurent expansion in epsilon. Using Riemann zeta functions of up to weight six, we give fully analytic results for one integral; for a second, analytic results for all but the finite term; for the third, analytic results for all but the last two coefficients in the Laurent expansion. The remaining coefficients are given numerically to sufficiently high accuracy for phenomenological applications.

 G. Heinrich, T. Huber, D.A. Kosower, V.A. Smirnov Phys.Lett. B678 359-366 2009 PDF PostScript arXiv

TTP09-05 Quark and gluon form factors to three loops

TTP09-05 Quark and gluon form factors to three loops

We compute the form factors of the photon-quark-anti-quark vertex and the effective vertex of a Higgs boson and two gluons to three-loop order within massless perturbative Quantum Chromodynamics. These results provide building blocks for many third-order cross sections. Furthermore, this is the first calculation of complete three-loop vertex corrections.

 P.A. Baikov, K.G. Chetyrkin, A.V. Smirnov, V.A. Smirnov, M. Steinhauser Phys.Rev.Lett. 102 212002 2009 PDF PostScript arXiv

TTP09-04 EDM constraints on flavored CP-violating phases

TTP09-04 EDM constraints on flavored CP-violating phases

The CP-violating phenomenology of the MSSM with Minimal Flavor Violation (MFV) in the lepton sector is revisited. To this end, the most general parametrizations of the slepton soft-breaking terms are constructed assuming a seesaw mechanism of type I. After a critical reassessment of how the CP-symmetry is broken within the MFV framework, all possible CP-violating phases are introduced. From the strong hierarchy of their contributions to the Electric Dipole Moments (EDMs), these phases are split into three classes: flavor-blind, flavor-diagonal and flavor off-diagonal. In particular, the phases from the neutrino sector belong to the last class; they start to contribute only at the second order in the mass-insertion approximation and have thus a negligible effect. It is then shown that to each class of phases corresponds a unique largely dominant term in the MFV expansion. Numerically, for a realistic range of MSSM and neutrino parameters, such that B(mu –> e gamma) does not exceed its experimental bound, the three types of phases are found to be allowed by the current bound on the electron EDM, though the next generation of experiments should constrain tightly the flavor-blind phase. Finally, we relax the MFV hypothesis and show how in the general MSSM, the MFV operator basis can be used to judge of the naturality of the slepton soft-breaking terms.

 Mercolli, Lorenzo and Smith, Christopher Nucl.Phys. B817 1-24 2009 PDF PostScript arXiv

TTP09-03 Current status of FORM parallelization

TTP09-03 Current status of FORM parallelization

We report on the status of the current development in parallelization of the symbolic manipulation system FORM. There are two parallel versions available, one is based on POSIX threads and is optimal for modern multicore computers while another one uses MPI and can be used to parallelize FORM on clusters and Massive Parallel Processing systems. Most of existing FORM programs will be able to take advantage of the parallel execution, without the need for modifications. In some cases some minor additions may be needed.

 M.Tentyukov and J.A.M.Vermaseren Proceedings of the ACAT08, 3-7 November 2008, Erice, Italy. Published as PDF PostScript

TTP09-02 NNLO vertex corrections in charmless hadronic B decays: Real part

TTP09-02 NNLO vertex corrections in charmless hadronic B decays: Real part

We compute the real part of the 2-loop vertex corrections for charmless hadronic B decays, completing the NNLO calculation of the topological tree amplitudes in QCD factorization. Among the technical aspects we show that the hard-scattering kernels are free of soft and collinear infrared divergences at the 2-loop level, which follows after an intricate subtraction procedure involving evanescent four quark operators. The numerical impact of the considered corrections is found to be moderate, whereas the factorization scale dependence of the topological tree amplitudes is significantly reduced at NNLO. We in particular do not find an enhancement of the phenomenologically important ratio |C/T| from the perturbative calculation.

 Guido Bell Nucl.Phys. B822 172-200 2009 PDF PostScript arXiv

TTP09-01 The supersymmetric Higgs sector and B-anti-B mixing for large tan beta

TTP09-01 The supersymmetric Higgs sector and B-anti-B mixing for large tan beta

We match the Higgs sector of the most general flavour breaking and CP violating minimal supersymmetric standard model (MSSM) onto a generic two-Higgs-doublet model, paying special attention to the definition of $\tan\beta$ in the effective theory. In particular no $\tan\beta$-enhanced loop corrections appear in the relation to $\tan\beta$ defined in the $\overline{\textrm{DR}}$ scheme in the MSSM. The corrections to the Higgs-mediated flavour-changing amplitudes which result from this matching are especially relevant for the $B_d$ and $B_s$ mass differences $\dm_{d,s}$ for minimal flavour violation, where the superficially leading contribution vanishes. We give a symmetry argument to explain this cancellation and perform a systematic study of all Higgs-mediated effects, including Higgs loops. The corrections to $\dm_s$ are at most 7\% for $\mu&gt;0$ and $M_A &lt; 600\gev$ if constraints from other observables are taken into account. For $\mu&lt;0$ they can be larger, but are always less than about 20\%. Contrary to recent claims we do not find numerically large contributions here, nor do we find any $\tan\beta$-enhanced contributions from loop corrections to the Higgs potential in $B^+ \to \tau^+ \nu$ or $B \to X_s \gamma$. We further update supersymmetric loop corrections to the Yukawa couplings, where we include all possible CP-violating phases and correct errors in the literature. The possible presence of CP-violating phases generated by Higgs exchange diagrams is briefly discussed as well. Finally we provide improved values for the bag factors $P^{\rm VLL}_1$, $P^{\rm  LR}_2$, and $P^{\rm SLL}_1$ at the electroweak scale.
 Martin Gorbahn, Sebastian Jäger, Ulrich Nierste and Stephanie Trine Phys.Rev. D84 034030 2011 PDF PostScript arXiv