Gudrun Hiller

Bio: Gudrun Hiller is an academic researcher from Technical University of Dortmund. The author has contributed to research in topics: Physics beyond the Standard Model & CP violation. The author has an hindex of 36, co-authored 95 publications receiving 4850 citations. Previous affiliations of Gudrun Hiller include CERN & Ludwig Maximilian University of Munich.

A Comparative study of the decays $B \to$ ($K$, $K^{*)} \ell^+ \ell^-$ in standard model and supersymmetric theories

Abstract: Using improved theoretical calculations of the decay form factors in the Light Cone-QCD sum rule approach, we investigate the decay rates, dilepton invariant mass spectra and the forward-backward (FB) asymmetry in the decays B → (K, K ∗ )l + l − (l ± = e ± , µ ± , τ ± ) in the standard model (SM) and a number of popular variants of the supersymmetric (SUSY) models. Theoretical precision on the differential decay rates and FB-asymmetry is estimated in these theories taking into account various parametric uncertainties. We show that existing data on B → Xsγ and the experimental upper limit on the branching ratio B(B → K ∗ µ + µ − ) provide interesting bounds on the coefficients of the underlying effective theory. We argue that the FB-asymmetry in B → K ∗ l + l − constitutes a precision test of the SM and its measurement in forthcoming experiments may reveal new physics. In particular, the presently allowed largetan β solutions in SUGRA models, as well as more general flavor-violating SUSY models, yield FB-asymmetries which are characteristically different from the corresponding ones in the SM.

Angular distributions of B̄ → Kl̄l decays

Abstract: We model-independently analyze the angular distributions of → Kl decays, l = e,μ, for low dilepton mass using QCD factorization. Besides the decay rate, we study the forward-backward asymmetry AlFB and a further observable, FlH, which gives rise to a flat term in the angular distribution. We find that in the Standard Model FlH∝ml2, hence vanishing FeH and FμH of around 2% (exact value depends on cuts) with a very small theoretical uncertainty of a few percent. We also give predictions for RK, the ratio of → Kμ to → Kēe decay rates. We analytically show using large recoil symmetry relations that in the Standard Model RK equals one up to lepton mass corrections of the order 10−4 including αs and subleading 1/E power corrections. The New Physics reach of the observables from the → Kl angular analysis is explored together with RK and the s → l and → Xsl branching ratios for both l = e and l = μ. We find substantial room for signals from (pseudo-) scalar and tensor interactions beyond the Standard Model. Experimental investigations of the → Kμ angular distributions are suitable for the LHC environment and high luminosity B factories, where also studies of the electron modes are promising.

Angular Distributions of B -> K ll Decays

Abstract: We model-independently analyze the angular distributions of B -> K ll decays, l = e, mu, for low dilepton mass using QCD factorization. Besides the decay rate, we study the forward-backward asymmetry A_FB^l and a further observable, F_H^l, which gives rise to a flat term in the angular distribution. We find that in the Standard Model F_H^l ~ m_l^2, hence vanishing F_H^e and F_H^mu of around 2% (exact value depends on cuts) with a very small theoretical uncertainty of a few percent. We also give predictions for R_K, the ratio of B -> K mu mu to B -> K ee decay rates. We analytically show using large recoil symmetry relations that in the Standard Model R_K equals one up to lepton mass corrections of the order 10^(-4). The New Physics reach of the observables from the B -> K ll angular analysis is explored together with R_K and the B_s -> ll and B -> X_s ll branching ratios for both l = e and l = mu. We find substantial room for signals from (pseudo-) scalar and tensor interactions beyond the Standard Model. Experimental investigations of the B -> K mu mu angular distributions are suitable for the LHC environment and high luminosity B factories, where also studies of the electron modes are promising.

$R_K$ and future $b \to s \ell \ell$ BSM opportunities

Abstract: Flavor changing neutral current $|\Delta B|=|\Delta S|=1$ processes are sensitive to possible new physics at the electroweak scale and beyond, providing detailed information about flavor, chirality and Lorentz structure. Recently the LHCb collaboration announced a $2.6 \sigma$ deviation in the measurement of $R_K={\cal{B}}(\bar B \to \bar K \mu \mu)/{\cal{B}}(\bar B \to \bar K ee)$ from the standard model's prediction of lepton universality. We identify dimension six operators which could explain this deviation and study constraints from other measurements. Vector and axial-vector four-fermion operators with flavor structure $\bar s b \bar \ell \ell$ can provide a good description of the data. Tensor operators cannot describe the data. Pseudo-scalar and scalar operators only fit the data with some fine-tuning; they can be further probed with the $\bar B \to \bar K ee$ angular distribution. The data appears to point towards $C_9^{\rm NP \mu} = -C_{10}^{\rm NP \mu }<0$, an $SU(2)_{L}$ invariant direction in parameter space supported by $R_K$, the $\bar B \to \bar K^* \mu \mu$ forward-backward asymmetry and the $\bar B_s \to \mu \mu$ branching ratio, which is currently allowed to be smaller than the standard model prediction. We present two leptoquark models which can explain the FCNC data and give predictions for the LHC and rare decays.

Improved model-independent analysis of semileptonic and radiative rare B decays

Abstract: We update the branching ratios for the inclusive decays $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{s}{l}^{+}{l}^{\ensuremath{-}}$ and the exclusive decays $\stackrel{\ensuremath{\rightarrow}}{B}{(K,K}^{*}{)l}^{+}{l}^{\ensuremath{-}},$ with $l=e, \ensuremath{\mu},$ in the standard model by including the explicit $O({\ensuremath{\alpha}}_{s})$ and ${\ensuremath{\Lambda}}_{\mathrm{QCD}}{/m}_{b}$ corrections. This framework is used in conjunction with the current measurements of the branching ratios for $\stackrel{\ensuremath{\rightarrow}}{B}{X}_{s}\ensuremath{\gamma}$ and $\stackrel{\ensuremath{\rightarrow}}{B}{\mathrm{Kl}}^{+}{l}^{\ensuremath{-}}$ decays and upper limits on the branching ratios for the decays $\stackrel{\ensuremath{\rightarrow}}{B}{(K}^{*}{,X}_{s}{)l}^{+}{l}^{\ensuremath{-}}$ to work out bounds on the Wilson coefficients ${C}_{7},$ ${C}_{8},$ ${C}_{9}$ and ${C}_{10}$ appearing in the effective Hamiltonian formalism. The resulting bounds are found to be consistent with the predictions of the standard model and some variants of supersymmetric theories. We illustrate the constraints on supersymmetric parameters that the current data on rare B decays implies in the context of the minimal flavor violating model and in more general scenarios admitting additional flavor changing mechanisms. Precise measurements of the dilepton invariant mass distributions in the decays $\stackrel{\ensuremath{\rightarrow}}{B}{(X}_{s}{,K}^{*}{,K)l}^{+}{l}^{\ensuremath{-}},$ in particular in the lower dilepton mass region, and the forward-backward asymmetry in the decays $\stackrel{\ensuremath{\rightarrow}}{B}{(X}_{s}{,K}^{*}{)l}^{+}{l}^{\ensuremath{-}},$ will greatly help in discriminating among the SM and various supersymmetric theories.

Phd by thesis

Abstract: Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Quantum Theory of Fields

Abstract: To say that this is the best book on the quantum theory of fields is no praise, since to my knowledge it is the only book on this subject But it is a very good and most useful book The original was written in German and appeared in 1942 This is a translation with some minor changes A few remarks have been added, concerning meson theory and nuclear forces, also footnotes referring to modern work in this field, and finally an appendix on the symmetrization of the energy momentum tensor according to Belinfante Quantum Theory of Fields Prof Gregor Wentzel Translated from the German by Charlotte Houtermans and J M Jauch Pp ix + 224, (New York and London: Interscience Publishers, Inc, 1949) 36s

Averages of b-hadron, c-hadron, and tau-lepton properties as of early 2012

Abstract: This article reports world averages of measurements of b-hadron, c-hadron, and tau-lepton properties obtained by the Heavy Flavor Averaging Group (HFAG) using results available through the end of 2011. In some cases results available in the early part of 2012 are included. For the averaging, common input parameters used in the various analyses are adjusted (rescaled) to common values, and known correlations are taken into account. The averages include branching fractions, lifetimes, neutral meson mixing parameters, CP violation parameters, parameters of semileptonic decays and CKM matrix elements.