Markus Finkemeier's research while affiliated with Harvard University and other places

Publications (28)

Article
We compute branching ratios and invariant mass distributions of the tau decays into four pions. The hadronic matrix elements are obtained by starting from the structure of the hadronic current in chiral limit and then implementing low-lying resonances in the dierent channels with slowly varying coupling constants. Reasonable agreement with experime...
Article
Reparametrization invariance, a symmetry of heavy quark effective theory, appears in different forms in the literature. The most commonly cited forms of the reparametrization transformation are shown to induce the same constraints on operators that do not vanish under the equation of motion to order 1/m2, and to be related by a redefinition of the...
Article
Predictions for decay rates and distributions for τ decays into final states with kaons are discussed and compared with recent measurements. Special emphasis is put on new constraints for the vector current contribution in the KKπ decay modes. For the Kππ modes, disagreements with the experimental results can be traced back to the K1 widths.
Article
We review a variety of topics related to hadronic structure functions in exclusive semihadronic tau decays. We introduce the concept of structure functions and summarize the most important concepts. We then calculate the decay τ → 3πντ for very small hadronic invariant mass to one loop in Chiral Perturbation Theory. New interesting features emerge...
Article
We consider the scalar form factor in τ → Kπν� decays. It receives contribu- tions both from the scalar resonance K ∗ 0(1430) and from the scalar projection of off-shell vector resonances. We construct a model for the hadronic current which includes the vector resonances K ∗(892) and K ∗(1410) and the scalar resonance K ∗ 0(1430). The parameters of...
Article
We consider the scalar form factor inτ →K πν τ decays. It receives contributions both from the scalar resonanceK*0(1430) and from the scalar projection of off-shell vector resonances. We construct a model for the hadronic current which includes the vector resonancesK*(892) andK*(1410) and the scalar resonanceK*0(1430). The parameters of the model...
Article
In a small window of phase space, chiral perturbation theory can be used to make standard model predictions for {tau} decays into two and three pions. For {tau}{r_arrow}2{pi}{nu}{sub {tau}}, we give the analytical result for the relevant form factor {ital F}{sub {ital V}} up to two loops, then calculate the differential spectrum and compare with av...
Article
We reexamine radiative corrections to πl2 and Kl2 decays. We perform a matching calculation, including vector and axial vector resonances as explicit degrees of freedom in the long distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by comparing with model independent estimates, we scrutinize the m...
Article
The heavy quark effective field theory Lagrangian is renormalized to order 1/m^2. Our technique eliminates operators that vanish by the equation of motion by continuously redefining the heavy quark fields during renormalization. It is consequently only necessary to calculate the running of the operators that do not vanish by the equation of motion....
Article
We review current issues in exclusive semileptonic tau decays. We present the formalism of structure functions, and then discuss predictions for final states with kaons, for decays into four pions and for radiative corrections to the decay into a single pion. Implications for testing the standard model at low energies are discussed.
Article
Hadronic decays rates of the $\tau$ lepton into multi meson final states are presented. The structure of the hadronic matrix elements for various decay modes is discussed. The formalism of structure functions allows for a detailed test of these matrix elements. Various correlations are discussed which are sensitive to possible CP violation and new...
Article
Predictions for semi-leptonic decay rates of the lepton into two meson final states K Gamma 0 ; K 0 Gamma ; K 0 K Gamma ; and three meson final states K Gamma Gamma K + ; K 0 Gamma K 0 ; K S Gamma K S ; K S Gamma KL ; KL Gamma KL ; K Gamma 0 K 0 ; 0 0 K Gamma ; K Gamma Gamma + ; Gamma K 0 0 are derived. The hadronic matrix elements are expressed in...
Article
We report on our reexamination of the radiative corrections to $\pi_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, using a specific model with vector meson dominance in the long distance part and the parton model in the short distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by com...
Article
We calculate the radiative corrections to the decays τ → Mντ and M → μνμ, where the meson M is M = π or K. We perform a complete calculation, which includes internal bremsstrahlung and structure dependent radiation in the radiative decays and point meson, hadronic structure dependent and short distance contributions in the virtual corrections. Our...
Article
We have calculated the radiative corrections to the decay $\tau\to \pi(K) \nu_\tau$, taking to account internal bremsstrahlung and structure dependent radiation in the radiative decay and point meson, hadronic structure dependent and short distance contributions in the virtual corrections. We display the spectra of the photon energy and of the pion...
Article
We reexamine radiative corrections to $\pi_{l2}$ and $K_{l2}$ decays. We perform a matching calculation, including vector and axial vector resonances as explicit degrees of freedom in the long distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by comparing with model independent estimates, we scru...
Article
We study the dynamical effects of nonvanishing pseudoscalar masses in [tau] decays into three mesons. The hadronic matrix elements are obtained by using the chiral Lagrangian of the order [ital O]([ital P][sup 2]), including the quark mass terms which explicitly break the chiral symmetry, and implementing the low-lying resonances in the different c...
Article
In a previous paper we have calculated the decay $\tau\to\pi\nu_\tau\gamma$. We used a given relative sign between the internal bremsstrahlung and the structure dependent radiation, which has been used by several other authors before. However, we believe that there are good arguments why the opposite sign is the physical one. We briefly discuss the...
Article
We consider $K_{l2}$ decays to the order $O(\alpha)$. We perform a matching calculation, using a specific model with vector meson dominance in the long distance part and the parton model in the short distance part. By considering the dependence on the matching scale and on the hadronic parameters, and by comparing with the leading model independent...
Article
We have calculated the radiative corrections to the decay � → �(K)�τ, taking to ac- count internal bremsstrahlung and structure dependent radiation in the radiative decay and point meson, hadronic structure dependent and short distance contributions in the virtual corrections. We display the spectra of the photon energy and of the pion-photon invar...
Article
We calculate the radiative corrections to the decays $\tau\to M \nu_\tau$ and $\pi \to l \nu_\l$, where the meson $M$ is $M=\pi$ or $K$ and the lepton $l$ is $l = e$ or $\mu$. We perform a complete calculation, which includes internal bremsstrahlung and structure dependent radiation in the radiative decays and point meson, hadronic structure depend...
Article
We compute branching ratios and invariant mass distributions of the tau decays into four pions. The hadronic matrix elements are obtained by starting from the structure of the hadronic current in chiral limit and then implementing low-lying resonances in the different channels with slowly varying coupling constants. Reasonable agreement with experi...
Article
We report the results of our improved calculation of the radiative corrections to the decay tau --> pi(K)nutau, which includes internal bremsstrahlung and structure dependent radiation in the radiative decay and point meson, hadronic structure dependent and short distance contributions in the virtual corrections. Our result for the radiative correc...
Article
We have calculated the radiative corrections to the decay τ->π(K)v_τ, taking to account internal bremsstrahlung and structure dependent radiation in the radiative decay and set point meson, hadronic structure dependent and short distance contributions in the virtual corrections. We display the spectra of the photon energy and of the pion-photon inv...
Article
We have calculated the decay τ→νπ(K)γ. We present the photon energy spectrum, the meson-photon invariant mass spectrum, and the integrated rate as a function of a photon energy cut or an invariant mass cut. Both the internal bremsstrahlung and the structure-dependent radiation have been taken into account. To this aim we have parametrized the form...
Article
Full-text available
We have calculated the O(α) radiative corrections to the tau decay τ→π (K) ν, taking into account both the point meson contribution and the structure dependent radiation. We find for the ratio Γ(τ→πν)(γ))/Γ(π→μν(γ)) a radiative correction of + 1.2% and for Γ(τ→Kν(γ))/Γ(K→μν(γ)) one of + 2.0%. We compare our results with an earlier estimation and wi...
Article
The axial form factors for the Kl4 decay are calculated using models with hidden local symmetry to describe JP=1- resonances. The relation between this approach and low-energy expansion is clarified. It is shown that the explicit breaking of chiral symmetry has no significant effect on the predictions. It turns out that in order to achieve a satisf...

Citations

... From the experimental determination of radiative pion decay, the SDP W is equal to 0.4685 ± 0.0353. In the literature, these FFs have been parametrised using the Breit-Wigner type resonances [2], the Light Front Quark Model [3] and the Resonance jPT [4]. However, the use of vastly di erent approaches a ected the predictions of the decay rate and spectrum and the value as well as the sign of W. We calculate these FFs using the method of light-cone sum rules (LCSR) in a consistent way [5]. ...
... Electroweak effects contributing to r e/µ K have been calculated to order e 2 p 4 in chiral perturbation theory, e.g. [78,79]. ...
... 1 As already pointed out in ref. [18], there is a different convention for the definitions of the form factors involved in eqs. (2.5) and (2.6) with those reported in Decker and Finkemeier's (DF) work [21]. Specifically, ...
... To see this, note that the relation between the HPET spinor and the Dirac spinor in eq. (2.4) can be inverted [42] u ...
... A similar search was performed by CMS [61]. An additional bound comes from the current uncertainties in the measured branching fractions for τ → P ν τ (P = π, K) [62] and the uncertainty in their theoretical predictions [63], ...
... where δR τ /P accounts for the radiative corrections to Γ(τ → P ν τ )/Γ(P → µν µ ), P ∈ {π, K}, which have been estimated as [98][99][100][101][102] δR τ /π = (0.16 ± 0.14)%, ...
... As the form-factor phases fitted via a superposition of Breit-Wigner functions with complex coefficients do not vanish at threshold and violate Watson's final-state interaction theorem before the higher resonances start to play an effect [31][32][33], we cannot rely on the formalism developed in refs. [46][47][48][49] to study JHEP05(2020)151 Figure 1. Tree-level Feynman diagrams for the decay τ − →K 0 π − ν τ (left) and its CP -conjugated mode τ + → K 0 π +ν τ (right) within the SM. ...
... where δR τ /P accounts for the radiative corrections to Γ(τ → P ν τ )/Γ(P → µν µ ), P ∈ {π, K}, which have been estimated as [98][99][100][101][102] δR τ /π = (0.16 ± 0.14)%, ...
... A fit between the obtained results and the experimental values led to a determination of low-energy constants of the chiral Lagrangian under large- N c assumption. A model-dependent calculation of form factors was carried out in [62] using chiral Lagrangian with hidden local symmetry where vector mesons, J P = 1 − , play the role of gauge bosons. The results were in significantly worse agreement with experiment compared with ChPT results and suggested the inclusion of a scalr J P = 0 + resonance in the ππ channel. ...
... Another useful feature of HQET is that loop corrections are scaleless [50], and therefore they vanish when using dim. reg. . ...