ArcAdiAThe DSpace digital repository system captures, stores, indexes, preserves, and distributes digital research material.http://dspace-roma3.caspur.it:802016-07-26T21:46:46Z2016-07-26T21:46:46ZAn improved Standard Model prediction of BR(B →τν) and its implicationsfor New PhysicsBona, MarcellaCiuchini, MarcoFranco, EnricoLubicz, VittorioMartinelli, GuidoParodi, FabrizioPierini, MaurizioSchiavi, CarloSilvestrini, LucaSordini, ViolaStocchi, AchilleTarantino, CeciliaVagnoni, Vincenzohttp://hdl.handle.net/2307/2272011-12-22T13:34:34Z2010-02-24T23:00:00Z<Title>An improved Standard Model prediction of BR(B →τν) and its implicationsfor New Physics</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Tarantino, Cecilia; Vagnoni, Vincenzo</Authors>
<Issue Date>2010-02-25</Issue Date>
<Is part of>Physics Letters B</Is part of>
<Volume>687</Volume>
<Pages>61-69</Pages>
<Abstract>The recently measured B →τν branching ratio allows to test the Standard Model by probing virtual
effects of new heavy particles, such as a charged Higgs boson. The accuracy of the test is currently
limited by the experimental error on BR(B → τν) and by the uncertainty on the parameters f B and
|Vub|. The redundancy of the Unitarity Triangle fit allows to reduce the error on these parameters and
thus to perform a more precise test of the Standard Model. Using the current experimental inputs, we
obtain BR(B →τν)SM = (0.84±0.11)×10−4, to be compared with BR(B →τν)exp = (1.73±0.34)×10−4.
The Standard Model prediction can be modified by New Physics effects in the decay amplitude as well
as in the Unitarity Triangle fit. We discuss how to disentangle the two possible contributions in the case
of minimal flavour violation at large tan β and generic loop-mediated New Physics. We also consider two
specific models with minimal flavour violation: the Type-II Two Higgs Doublet Model and the Minimal
Supersymmetric Standard Model.</Abstract>2010-02-24T23:00:00ZStatus of the Unitarity Triangle AnalysisBona, MarcellaCiuchini, MarcoFranco, EnricoLubicz, VittorioMartinelli, GuidoParodi, FabrizioPierini, MaurizioSchiavi, CarloSilvestrini, LucaSordini, ViolaStocchi, AchilleTarantino, CeciliaVagnoni, Vincenzohttp://hdl.handle.net/2307/2392011-12-22T13:39:36Z2008-12-31T23:00:00Z<Title>Status of the Unitarity Triangle Analysis</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Tarantino, Cecilia; Vagnoni, Vincenzo</Authors>
<Issue Date>2009</Issue Date>
<Pages>160-163</Pages>
<Abstract>We present an update of the Unitarity Triangle (UT) analysis, within the Standard Model (SM)
and beyond. Within the SM the main novelties are the inclusion in eK of the contributions of
x and fe 6= p /4 pointed out by A. J. Buras and D. Guadagnoli, and an accurate prediction of
BR(B→tn), by using the indirect determination of |Vub| from the UT fit, which can be compared
to the present experimental result. In the generalization of the UT analysis to investigate New
Physics (NP) effects, the estimate of x is more delicate and only the effect of fe 6= p /4 has
been included. We confirm an hint of NP in the Bs-¯Bs mixing at the 2.9s level, which makes a
comparison with new experimental data certainly desired.</Abstract>2008-12-31T23:00:00ZFirst evidence of new physics in b ↔ s transitionsBona, MarcellaCiuchini, MarcoFranco, EnricoLubicz, VittorioMartinelli, GuidoParodi, FabrizioPierini, MaurizioSchiavi, CarloSilvestrini, LucaSordini, ViolaStocchi, AchilleVagnoni, Vincenzohttp://hdl.handle.net/2307/2292011-12-22T13:34:55Z2009-11-30T23:00:00Z<Title>First evidence of new physics in b ↔ s transitions</Title>
<Authors>Bona, Marcella; Ciuchini, Marco; Franco, Enrico; Lubicz, Vittorio; Martinelli, Guido; Parodi, Fabrizio; Pierini, Maurizio; Schiavi, Carlo; Silvestrini, Luca; Sordini, Viola; Stocchi, Achille; Vagnoni, Vincenzo</Authors>
<Issue Date>2009-12</Issue Date>
<Is part of>PMC Physics A</Is part of>
<Volume>3</Volume>
<Abstract>We combine all the available experimental information on Bs mixing, including the very
recent tagged analyses of Bs → J/Ψϕ by the CDF and DØ collaborations. We find that the
phase of the Bs mixing amplitude deviates more than 3σ from the Standard Model
prediction. While no single measurement has a 3σ significance yet, all the constraints show
a remarkable agreement with the combined result. This is a first evidence of physics
beyond the Standard Model. This result disfavours New Physics models with Minimal
Flavour Violation with the same significance.</Abstract>2009-11-30T23:00:00ZImproved determination of the CKM Angle α from B --> π π decaysUTfit CollaborationBona, M.Ciuchini, MarcoFranco, E.Lubicz, VittorioMartinelli, G.Parodi, F.Pierini, M.Roudeau, P.Schiavi, C.Silvestrini, L.Sordini, V.Stocchi, A.Vagnoni, V.http://hdl.handle.net/2307/3892011-12-22T13:34:55Z2007-06-30T22:00:00Z<Title>Improved determination of the CKM Angle α from B --> π π decays</Title>
<Authors>UTfit Collaboration; Bona, M.; Ciuchini, Marco; Franco, E.; Lubicz, Vittorio; Martinelli, G.; Parodi, F.; Pierini, M.; Roudeau, P.; Schiavi, C.; Silvestrini, L.; Sordini, V.; Stocchi, A.; Vagnoni, V.</Authors>
<Issue Date>2007-07</Issue Date>
<Is part of>Physical Review D</Is part of>
<Volume>76</Volume>
<Pages>014015-014015-10</Pages>
<Abstract>Motivated by a recent paper that compares the results of the analysis of the CKM angle alpha in the frequentist and in the Bayesian approaches, we have reconsidered the information on the hadronic amplitudes, which helps in constraining the value of alpha in the standard model. We find that the Bayesian method gives consistent results irrespective of the parametrization of the hadronic amplitudes and that the results of the frequentist and Bayesian approaches are equivalent when comparing meaningful probability ranges or confidence levels. We also find that from B-->pipi decays alone the 95% probability region for alpha is the interval [80°, 170°], well consistent with recent analyses of the unitarity triangle where, by using all the available experimental and theoretical information, one gets alpha=(93±4)°. Last but not least, by using simple arguments on the hadronic matrix elements, we show that the unphysical region alpha~0, present in several experimental analyses, can be eliminated.</Abstract>2007-06-30T22:00:00ZModel-independent Constraints on ΔF=2 Operators and the Scale of New PhysicsUTfit CollaborationBona, M.Ciuchini, MarcoFranco, E.Lubicz, V.Martinelli, G.Parodi, F.Pierini, M.Roudeau, P.Schiavi, C.Silvestrini, L.Sordini, V.Stocchi, A.Vagnoni, V.http://hdl.handle.net/2307/3862011-12-22T13:34:34Z2008-02-29T23:00:00Z<Title>Model-independent Constraints on ΔF=2 Operators and the Scale of New Physics</Title>
<Authors>UTfit Collaboration; Bona, M.; Ciuchini, Marco; Franco, E.; Lubicz, V.; Martinelli, G.; Parodi, F.; Pierini, M.; Roudeau, P.; Schiavi, C.; Silvestrini, L.; Sordini, V.; Stocchi, A.; Vagnoni, V.</Authors>
<Issue Date>2008-03</Issue Date>
<Is part of>Journal of High Energy Physics</Is part of>
<Volume>03</Volume>
<Pages>1-23</Pages>
<Abstract>We update the constraints on new-physics contributions to ΔF = 2 processes from the generalized unitarity triangle analysis, including the most recent experimental developments. Based on these constraints, we derive upper bounds on the coefficients of the most general ΔF = 2 effective Hamiltonian. These upper bounds can be translated into lower bounds on the scale of new physics that contributes to these low-energy effective interactions. We point out that, due to the enhancement in the renormalization group evolution and in the matrix elements, the coefficients of non-standard operators are much more constrained than the coefficient of the operator present in the Standard Model. Therefore, the scale of new physics in models that generate new ΔF = 2 operators, such as next-to-minimal flavour violation, has to be much higher than the scale of minimal flavour violation, and it most probably lies beyond the reach of direct searches at the LHC.</Abstract>2008-02-29T23:00:00ZD--Dbar Mixing and New Physics: General Considerations and Constraints on the MSSMCiuchini, MarcoFranco, E.Guadagnoli, D.Lubicz, V.Pierini, M.Porretti, V.Silvestrini, L.http://hdl.handle.net/2307/3872011-12-22T13:34:55Z2007-10-31T23:00:00Z<Title>D--Dbar Mixing and New Physics: General Considerations and Constraints on the MSSM</Title>
<Authors>Ciuchini, Marco; Franco, E.; Guadagnoli, D.; Lubicz, V.; Pierini, M.; Porretti, V.; Silvestrini, L.</Authors>
<Issue Date>2007-11</Issue Date>
<Is part of>Physics Letters B</Is part of>
<Volume>655</Volume>
<Pages>162-166</Pages>
<Abstract>Combining the recent experimental evidence of D--Dbar mixing, we extract model-independent information on the mixing amplitude and on its CP-violating phase. Using this information, we present new constraints on the flavour structure of up-type squark mass matrices in supersymmetric extensions of the Standard Model.</Abstract>2007-10-31T23:00:00Z