Complementarity of Semileptonic BB to K2∗(1430)K_2^*(1430) and K∗(892)K^*(892) Decays in the Standard Model with Fourth Generation

The $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ $(l=\mu,\tau)$ decays are analyzed in the Standard Model extended to fourth generation of quarks (SM4). The decay rate, forward-backward asymmetry, lepton polarization asymmetries and the helicity fractions of the final state $K^{*}_{2}(1430)$ meson are obtained using the form factors calculated in the light cone sum rules (LCSR) approach. We have utilized the constraints on different fourth generation parameters obtained from the experimental information on $K$, $B$ and $D$ decays and from the electroweak precision data to explore their impact on the $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ decay. We find that the values of above mentioned physical observables deviate deviate significantly from their minimal SM predications. We also identify a number of correlations between various observables in $B\rightarrow K_{2}^{\ast}(1430)l^{+}l^{-}$ and $B\rightarrow K^{\ast}(892)l^{+}l^{-}$ decays. Therefore a combined analysis of these two decays will compliment each other in the searches of SM4 effects in flavor physics.Comment: 28 pages, 12 figure

Angular analysis of B --> V (--> P_1 P_2) l^+ l^- decays

The angular analysis of exclusive rare B-meson decays via intermediate vector mesons V into 4-body final states of two pseudo-scalars P_1, P_2 and a pair of light leptons l = e, mu offers a large set of observables. They can be used to test the electroweak short-distance couplings in the Standard Model and to search for New Physics. The two kinematic regions of low and high dilepton mass depend on short-distance physics in complementary ways and can be expanded in powers of Lambda_QCD/m_b. These expansions guide towards suitable combinations of observables allowing to i) reduce the hadronic uncertainties in the extraction of the short-distance couplings or ii) test the lattice QCD (B -> V) form factors in short-distance independent combinations. Several such possibilities of CP-averaged and CP-asymmetric (T-even and T-odd) quantities are presented for B_d^0 --> K^*0 (-> K pi) l^+ l^- and time-integrated CP-asymmetries without tagging for (anti-B_s, B_s) --> phi (--> K^- K^+) l^+ l^- decays in view of the latest B-factory and CDF results and the forthcoming LHCb measurements.Comment: 9 pages, 4 figures; Talk given at Discrete '10: Symposium on Prospects in the Physics of Discrete Symmetries, Rome, Italy, 6-11 Dec 201

Cornering New Physics in b --> s Transitions

We derive constraints on Wilson coefficients of dimension-six effective operators probing the b --> s transition, using recent improved measurements of the rare decays Bs --> mu+mu-, B --> K mu+mu- and B --> K* mu+mu- and including all relevant observables in inclusive and exclusive decays. We consider operators present in the SM as well as their chirality-flipped counterparts and scalar operators. We find good agreement with the SM expectations. Compared to the situation before winter 2012, we find significantly more stringent constraints on the chirality-flipped coefficients due to complementary constraints from B --> K mu+mu- and B --> K* mu+mu- and due to the LHCb measurement of the angular observable S_3 in the latter decay. We also list the full set of observables sensitive to new physics in the low recoil region of B --> K* mu+mu-.Comment: 18 pages, 6 figures, 4 tables. v3: typos correcte

Complete Anatomy of B -> K*ll and its angular distribution

We present a complete and optimal set of observables for the exclusive 4-body B meson decay B -> K*(->K pi) l+l- in the low dilepton mass region, that contains a maximal number of clean observables. This basis of observables is built in a systematic way. We show that all the previously defined observables and any observable that one can construct, can be expressed as a function of this basis. This set of observables contains all the information that can be extracted from the angular distribution in the cleanest possible way. We provide explicit expressions for the full and the uniangular distributions in terms of this basis. The conclusions presented here can be easily extended to the large-q^2 region. We study the sensitivity of the observables to right-handed currents and scalars. Finally, we present for the first time all the symmetries of the full distribution including massive terms and scalar contributions.Comment: 37 pages, 12 Figures. Corrected typo in Eqs. (29) and (44). Results and conclusions unchange

Implications from clean observables for the binned analysis of B -> K*ll at large recoil

We perform a frequentist analysis of q^2-dependent B-> K*(->Kpi)ll angular observables at large recoil, aiming at bridging the gap between current theoretical analyses and the actual experimental measurements. We focus on the most appropriate set of observables to measure and on the role of the q^2-binning. We highlight the importance of the observables P_i exhibiting a limited sensitivity to soft form factors for the search for New Physics contributions. We compute predictions for these binned observables in the Standard Model, and we compare them with their experimental determination extracted from recent LHCb data. Analyzing b->s and b->sll transitions within four different New Physics scenarios, we identify several New Physics benchmark points which can be discriminated through the measurement of P_i observables with a fine q^2-binning. We emphasise the importance (and risks) of using observables with (un)suppressed dependence on soft form factors for the search of New Physics, which we illustrate by the different size of hadronic uncertainties attached to two related observables (P_1 and S_3). We illustrate how the q^2-dependent angular observables measured in several bins can help to unravel New Physics contributions to B-> K*(->Kpi)ll, and show the extraordinary constraining power that the clean observables will have in the near future. We provide semi-numerical expressions for these observables as functions of the relevant Wilson coefficients at the low scale.Comment: 50 pages, 21 figures. Improved form factor analysis, conclusions unchanged. Plots with full resolution. Version published in JHE

Supersymmetric constraints from Bs -> mu+mu- and B -> K* mu+mu- observables

We study the implications of the recent LHCb limit and results on Bs -> mu+mu- and B -> K* mu+mu- observables in the constrained SUSY scenarios. After discussing the Standard Model predictions and carefully estimating the theoretical errors, we show the constraining power of these observables in CMSSM and NUHM. The latest limit on BR(Bs -> mu+mu-), being very close to the SM prediction, constrains strongly the large tan(beta) regime and we show that the various angular observables from B -> K* mu+mu- decay can provide complementary information in particular for moderate tan(beta) values.Comment: 30 pages, 14 figure

Model-independent constraints on new physics in b --> s transitions

We provide a comprehensive model-independent analysis of rare decays involving the b --> s transition to put constraints on dimension-six Delta(F)=1 effective operators. The constraints are derived from all the available up-to-date experimental data from the B-factories, CDF and LHCb. The implications and future prospects for observables in b --> s l+l- and b --> s nu nu transitions in view of improved measurements are also investigated. The present work updates and generalises previous studies providing, at the same time, a useful tool to test the flavour structure of any theory beyond the SM.Comment: 1+39 pages, 12 figures, 3 tables. v2: minor modifications, typos corrected, references added, version to be published in JHE

Bayesian Fit of Exclusive b→sℓˉℓb \to s \bar\ell\ell Decays: The Standard Model Operator Basis

We perform a model-independent fit of the short-distance couplings $C_{7,9,10}$ within the Standard Model set of $b\to s\gamma$ and $b\to s\bar\ell\ell$ operators. Our analysis of $B \to K^* \gamma$, $B \to K^{(*)} \bar\ell\ell$ and $B_s \to \bar\mu\mu$ decays is the first to harness the full power of the Bayesian approach: all major sources of theory uncertainty explicitly enter as nuisance parameters. Exploiting the latest measurements, the fit reveals a flipped-sign solution in addition to a Standard-Model-like solution for the couplings $C_i$. Each solution contains about half of the posterior probability, and both have nearly equal goodness of fit. The Standard Model prediction is close to the best-fit point. No New Physics contributions are necessary to describe the current data. Benefitting from the improved posterior knowledge of the nuisance parameters, we predict ranges for currently unmeasured, optimized observables in the angular distributions of $B\to K^*(\to K\pi)\,\bar\ell\ell$.Comment: 42 pages, 8 figures; v2: Using new lattice input for f_Bs, considering Bs-mixing effects in BR[B_s->ll]. Main results and conclusion unchanged, matches journal versio

The Benefits of B ---> K* l+ l- Decays at Low Recoil

Using the heavy quark effective theory framework put forward by Grinstein and Pirjol we work out predictions for B -> K* l+ l-, l = (e, mu), decays for a softly recoiling K*, i.e., for large dilepton masses sqrt{q^2} of the order of the b-quark mass m_b. We work to lowest order in Lambda/Q, where Q = (m_b, sqrt{q^2}) and include the next-to-leading order corrections from the charm quark mass m_c and the strong coupling at O(m_c^2/Q^2, alpha_s). The leading Lambda/m_b corrections are parametrically suppressed. The improved Isgur-Wise form factor relations correlate the B -> K* l+ l- transversity amplitudes, which simplifies the description of the various decay observables and provides opportunities for the extraction of the electroweak short distance couplings. We propose new angular observables which have very small hadronic uncertainties. We exploit existing data on B -> K* l+ l- distributions and show that the low recoil region provides powerful additional information to the large recoil one. We find disjoint best-fit solutions, which include the Standard Model, but also beyond-the-Standard Model ones. This ambiguity can be accessed with future precision measurements.Comment: 31 pages, 8 figures; Instability near minimal recoil from numerics removed, Fig. 1 replaced and minor shifts in short distance uncertainties in SM predictions; typos corrected and references added; main results and conclusions unchange

More Benefits of Semileptonic Rare B Decays at Low Recoil: CP Violation

We present a systematic analysis of the angular distribution of Bbar -> Kbar^\ast (-> Kbar pi) l^+ l^- decays with l = e, mu in the low recoil region (i.e. at high dilepton invariant masses of the order of the mass of the b-quark) to account model-independently for CP violation beyond the Standard Model, working to next-to-leading order QCD. From the employed heavy quark effective theory framework we identify the key CP observables with reduced hadronic uncertainties. Since some of the CP asymmetries are CP-odd they can be measured without B-flavour tagging. This is particularly beneficial for Bbar_s,B_s -> phi(-> K^+ K^-) l^+ l^- decays, which are not self-tagging, and we work out the corresponding time-integrated CP asymmetries. Presently available experimental constraints allow the proposed CP asymmetries to be sizeable, up to values of the order ~ 0.2, while the corresponding Standard Model values receive a strong parametric suppression at the level of O(10^-4). Furthermore, we work out the allowed ranges of the short-distance (Wilson) coefficients C_9,C_10 in the presence of CP violation beyond the Standard Model but no further Dirac structures. We find the Bbar_s -> mu^+ mu^- branching ratio to be below 9*10^-9 (at 95% CL). Possibilities to check the performance of the theoretical low recoil framework are pointed out.Comment: 18 pages, 3 fig.; 1 reference and comment on higher order effects added; EOS link fixed. Minor adjustments to Eqs 4.1-4.3 to match the (lower) q^2-cut as given in paper. Main results and conclusions unchanged; v3+v4: treatment of exp. uncert. in likelihood-function in EOS fixed and constraints from scan on C9,C10 updated (Fig 2,3 and Eqs 3.2,3.3). Main results and conclusions absolutely unchange