WorldWideScience

Sample records for a4 flavour symmetry

  1. Matter inflation with A4 flavour symmetry breaking

    We discuss model building in tribrid inflation, which is a framework for realising inflation in the matter sector of supersymmetric particle physics models. The inflaton is a D-flat combination of matter fields, and inflation ends by a phase transition in which some Higgs field obtains a vacuum expectation value. We first describe the general procedure for implementing tribrid inflation in realistic models of particle physics that can be applied to a wide variety of BSM particle physics models around the GUT scale. We then demonstrate how the procedure works for an explicit lepton flavour model based on an A4 family symmetry. The model is both predictive and phenomenologically viable, and illustrates how tribrid inflation connects cosmological and particle physics parameters. In particular, it predicts a relation between the neutrino Yukawa coupling and the running of the spectral index αs. We also show how topological defects from the flavour symmetry breaking can be avoided automatically

  2. Combining Pati-Salam and Flavour Symmetries

    Feldmann, Thorsten; Kilian, Wolfgang; Luhn, Christoph

    2015-01-01

    We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements.

  3. Combining Pati-Salam and flavour symmetries

    Feldmann, Thorsten; Hartmann, Florian; Kilian, Wolfgang; Luhn, Christoph

    2015-10-01

    We construct an extension of the Standard Model (SM) which is based on grand unification with Pati-Salam symmetry. The setup is supplemented with the idea of spontaneous flavour symmetry breaking which is mediated through flavon fields with renormalizable couplings to new heavy fermions. While we argue that the new gauge bosons in this approach can be sufficiently heavy to be irrelevant at low energies, the fermionic partners of the SM quarks, in particular those for the third generation, can be relatively light and provide new sources of flavour violation. The size of the effects is constrained by the observed values of the SM Yukawa matrices, but in a way that is different from the standard minimal-flavour violation approach. We determine characteristic deviations from the SM that could eventually be observed in future precision measurements.

  4. Extracting gamma Through Flavour-Symmetry Strategies

    Fleischer, Robert

    2002-01-01

    A brief overview of flavour-symmetry strategies to extract the angle gamma of the unitarity triangle is given, focusing on B --> pi K modes and the B_d --> pi^+ pi^-, B_s --> K^+ K^- system. We discuss also a variant of the latter approach for the e^+ e^- B-factories, where B_s --> K^+ K^- is replaced by B_d --> pi^{+/-} K^{+/-}.

  5. Discrete Symmetries and Models of Flavour Mixing

    King, Stephen F.

    2015-07-01

    In this talk we shall give an overview of the role of discrete symmetries, including both CP and family symmetry, in constructing unified models of quark and lepton (including especially neutrino) masses and mixing. Various different approaches to model building will be described, denoted as direct, semi-direct and indirect, and the pros and cons of each approach discussed. Particular examples based on Δ(6n2) will be discussed and an A to Z of Flavour with Pati-Salam will be presented.

  6. Effective theories with broken flavour symmetry

    The work of Ovrut and Schnitzer on effective theories derived from a non Abelian Gauge Theory is generalised to include the physically interesting case of broken flavour symmetry. The calculations are performed at the 1-loop level. It is shown that at an intermediate stage in the calculations two distinct renormalised gauge coupling constants appear, one describing gauge field coupling to heavy particles and the other describing coupling to light particles. Appropriately modified Slavnov-Taylor identities are shown to hold. A simple alternative to the Ovrut-Schnitzer rules for calculating with effective theories is also considered

  7. Lepton-flavour violation in a Pati-Salam model with gauged flavour symmetry

    Feldmann, Thorsten; Moch, Paul

    2016-01-01

    Combining Pati-Salam (PS) and flavour symmetries in a renormalisable setup, we devise a scenario which produces realistic masses for the charged leptons. Flavour-symmetry breaking scalar fields in the adjoint representations of the PS gauge group are responsible for generating different flavour structures for up- and down-type quarks as well as for leptons. The model is characterised by new heavy fermions which mix with the Standard Model quarks and leptons. In particular, the partners for the third fermion generation induce sizeable sources of flavour violation. Focusing on the charged-lepton sector, we scrutinise the model with respect to its implications for lepton-flavour violating processes such as $\\mu \\rightarrow e\\gamma$, $\\mu\\rightarrow 3e$ and muon conversion in nuclei.

  8. A U(2)^3 flavour symmetry in Supersymmetry

    Sala, Filippo

    2012-01-01

    A U(2)^3 flavour symmetry acting on the first two generations of quarks partially explains the hierarchies of the yukawa couplings, and provides a natural embedding for Supersymmetry with heavier first two generations, where collider constraints are not in conflict with the requirement of naturalness and the SUSY CP problem is solved. Within this context a specific pattern of flavour symmetry breaking is considered. The K, B_d and B_s mixing amplitudes show a definite correlation that can resolve existing tensions in the CKM fit, pointing in this way to sbottom and gluino masses below about 1.5 TeV. Potentially sizeable contributions to both indirect and direct CP violation in B decays are allowed, even in the absence of flavour-blind phases. In case some effects are observed, the peculiar pattern in Delta(F) = 2 and Delta(B) = 1 observables may allow to distinguish between this and other models.

  9. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    Buccella, F. [Napoli Federico II Univ. (Italy). Dipartimento di Scienze Fisiche; INFN, Napoli (Italy); Hoegaasen, H. [University of Oslo, Department of Physics (Norway); Richard, J.M. [Universite Joseph Fourier-IN2P3-CNRS 53, Laboratoire de Physique Subatomique et Cosmologie, Grenoble (France); Sorba, P. [Laboratoire d' Annecy-le-Vieux de Physique Theorique (LAPTH) (France)

    2007-02-15

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty. (orig.)

  10. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty. (orig.)

  11. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    Buccella, F.; Høgaasen, H.; Richard, J.-M.; Sorba, P.

    2007-02-01

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.

  12. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    Buccella, F; Richard, J M; Sorba, Paul; Buccella, Franco; Hogaasen, Hallstein; Richard, Jean-Marc; Sorba, Paul

    2007-01-01

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.

  13. Chromomagnetism, flavour symmetry breaking and S-wave tetraquarks

    Buccella, Franco; Hogaasen, Hallstein; Richard, Jean-Marc; Sorba, Paul

    2006-01-01

    The chromomagnetic interaction, with full account for flavour-symmetry breaking, is applied to S-wave configurations containing two quarks and two antiquarks. Phenomenological implications are discussed for light, charmed, charmed and strange, hidden-charm and double-charm mesons, and extended to their analogues with beauty.

  14. The flavour problem and family symmetry beyond the Standard Model

    Dziewit, Bartosz; Richter, Monika; Zając, Sebastian; Zrałek, Marek

    2016-01-01

    In the frame of two Higgs doublet model we try to explain the lepton masses and mixing matrix elements assuming that neutrinos are Dirac particles. Discrete family symmetry groups, which are subgroups of U(3) up to the 1025 order are considered. Like in the one Higgs Standard Model, we found that discrete family symmetries do not give satisfactory answer for this basic questions in the flavour problem.

  15. The Symmetry behind Extended Flavour Democracy and Large Leptonic Mixing

    Silva-Marcos, Joaquim I

    2002-01-01

    We show that there is a minimal discrete symmetry which leads to the extended flavour democracy scenario constraining the Dirac neutrino, the charged lepton and the Majorana neutrino mass term ($M_R$) to be all proportional to the democratic matrix, with all elements equal. In particular, this discrete symmetry forbids other large contributions to $M_R$, such as a term proportional to the unit matrix, which would normally be allowed by a $S_{3L}\\times S_{3R}$ permutation symmetry. This feature is crucial in order to obtain large leptonic mixing, without violating 't Hooft's, naturalness principle.

  16. Flavour symmetry as a Spontaneously Broken Discrete Permutation Symmetry Embedded in Colour

    Törnqvist, N A

    1999-01-01

    A new mechanism for breaking an internal symmetry spontaneously is discussed, which is intermediate between the Nambu-Goldstone and Wigner modes of symmetry breaking. Here the quark-antiquark sea takes the role of the vacuum of the Nambu-Goldstone case. Flavour symmetry becomes a discrete permutation symmetry of the valence quarks with respect to the sea quarks, which can be spontaneously broken without generation of massless Goldstone bosons.

  17. Quark-flavour phenomenology of models with extended gauge symmetries

    Gauge invariance is one of the fundamental principles of the Standard Model of particles and interactions, and it is reasonable to believe that it also regulates the physics beyond it. In this thesis we have studied the theory and phenomenology of two New Physics models based on gauge symmetries that are extensions of the Standard Model group. Both of them are particularly interesting because they provide some answers to the question of the origin of flavour, which is still unexplained. Moreover, the flavour sector represents a promising field for the research of indirect signatures of New Physics, since after the first run of LHC we do not have any direct hint of it yet. The first model assumes that flavour is a gauge symmetry of nature, SU(3)3f, spontaneously broken by the vacuum expectation values of new scalar fields; the second model is based on the gauge group SU(3)c x SU(3)L x U(1)X, the simplest non-abelian extension of the Standard Model group. We have traced the complete theoretical building of the models, from the gauge group, passing through the nonanomalous fermion contents and the appropriate symmetry breakings, up to the spectra and the Feynman rules, with a particular attention to the treatment of the flavour structure, of tree-level Flavour Changing Neutral Currents and of new CP-violating phases. In fact, these models present an interesting flavour phenomenology, and for both of them we have analytically calculated the contributions to the ΔF=2 and ΔF=1 down-type transitions, arising from new tree-level and box diagrams. Subsequently, we have performed a comprehensive numerical analysis of the phenomenology of the two models. In both cases we have found very effective the strategy of first to identify the quantities able to provide the strongest constraints to the parameter space, then to systematically scan the allowed regions of the latter in order to obtain indications about the key flavour observables, namely the mixing parameters of the

  18. Minimal gauge-Higgs unification with a flavour symmetry

    Martinelli, Guido [Dip. di Fisica, Univ. di Roma ' La Sapienza' , and INFN, Sez. di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Salvatori, Matteo [Dep. de Fisica Teorica, C-XI, and Ist. de Fisica Teorica, C-XVI, Univ. Autonoma de Madrid, Cantoblanco, 28049 Madrid (Spain); Scrucca, Claudio Alessandro [Institut de Physique, Univ. de Neuchatel, Rue Breguet 1, 2000 Neuchatel (Switzerland); Silvestrini, Luca [Dip. di Fisica, Univ. di Roma ' La Sapienza' , and INFN, Sez. di Roma, Piazzale Aldo Moro 2, 00185 Rome (Italy); Physik-Department T31, TU-Muenchen, 85748 Garching (Germany)

    2005-10-15

    We show that a flavour symmetry a la Froggatt-Nielsen can be naturally incorporated in models with gauge-Higgs unification, by exploiting the heavy fermions that are anyhow needed to realize realistic Yukawa couplings. The case of the minimal five-dimensional model, in which the SU(2){sub L} x U(1){sub Y} electroweak group is enlarged to an SU(3){sub W} group, and then broken to U(1){sub em} by the combination of an orbifold projection and a Scherk-Schwarz twist, is studied in detail. We show that the minimal way of incorporating a U(1){sub F} flavour symmetry is to enlarge it to an SU(2){sub F} group, which is then completely broken by the same orbifold projection and Scherk-Schwarz twist. The general features of this construction, where ordinary fermions live on the branes defined by the orbifold fixed-points and messenger fermions live in the bulk, are compared to those of ordinary four-dimensional flavour models, and some explicit examples are constructed.

  19. Flavour symmetries in a renormalizable SO(10) model

    Ferreira, P M; Jurčiukonis, D; Lavoura, L

    2015-01-01

    In the context of a renormalizable supersymmetric SO(10) Grand Unified Theory, we consider the fermion mass matrices generated by the Yukawa couplings to a $\\mathbf{10} \\oplus \\mathbf{120} \\oplus \\overline{\\mathbf{126}}$ representation of scalars. We perform a complete investigation of the possibilities of imposing flavour symmetries in this scenario; the purpose is to reduce the number of Yukawa coupling constants in order to identify potentially predictive models. We have found that there are only 14 inequivalent cases of Yukawa coupling matrices, out of which 13 cases are generated by $Z_n$ symmetries, with suitable $n$, and one case is generated by a $Z_2 \\times Z_2$ symmetry. A numerical analysis of the 14 cases reveals that only two of them---dubbed A and B in the present paper---allow good fits to the experimentally known fermion masses and mixings.

  20. Flavour symmetries in a renormalizable SO(10) model

    Ferreira, P. M.; Grimus, W.; Jurčiukonis, D.; Lavoura, L.

    2016-05-01

    In the context of a renormalizable supersymmetric SO (10) Grand Unified Theory, we consider the fermion mass matrices generated by the Yukawa couplings to a 10 ⊕ 120 ⊕ 126 ‾ representation of scalars. We perform a complete investigation of the possibilities of imposing flavour symmetries in this scenario; the purpose is to reduce the number of Yukawa coupling constants in order to identify potentially predictive models. We have found that there are only 14 inequivalent cases of Yukawa coupling matrices, out of which 13 cases are generated by Zn symmetries, with suitable n, and one case is generated by a Z2 ×Z2 symmetry. A numerical analysis of the 14 cases reveals that only two of them-dubbed A and B in the present paper-allow good fits to the experimentally known fermion masses and mixings.

  1. SU(3) flavour symmetry breaking and charmed states

    By extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses we propose a method to determine charmed quark hadron masses including possible QCD isospin breaking effects. Initial results for some open charmed pseudoscalar meson states and singly and doubly charmed baryon states are encouraging and demonstrate the potential of the procedure. Essential for the method is the determination of the scale using singlet quantities, and to this end we also give here a preliminary estimation of the recently introduced Wilson flow scales.

  2. SU(3) flavour symmetry breaking and charmed states

    Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Najjar, J. [Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Hyogo (Japan); Perlt, H.; Schiller, A. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Pleiter, D. [Forschungszentrum Juelich GmbH (Germany). Juelich Supercomputing Centre (JSC); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Zanotti, J.M. [Adelaide Univ. (Australia). CSSM, School of Chemistry and Physics; Collaboration: QCDSF-UKQCD Collaborations

    2013-11-15

    By extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses we propose a method to determine charmed quark hadron masses including possible QCD isospin breaking effects. Initial results for some open charmed pseudoscalar meson states and singly and doubly charmed baryon states are encouraging and demonstrate the potential of the procedure. Essential for the method is the determination of the scale using singlet quantities, and to this end we also give here a preliminary estimation of the recently introduced Wilson flow scales.

  3. The CKM matrix from a scheme of flavour symmetry breaking

    A theoretical |VCKMth| mixing matrix which is a function of the four mass ratios and the CP violating phase α is derived from a simple scheme for breaking the flavour permutational symmetry. We assumed that the symmetry breaking pattern is the same in the u and d-sectors, and imposed a phenomenologically motivated constraint on the amount of mixing of singlet and doublet irreducible representations of S(3)L x S(3)R. A χ2 fit of the matrix of the absolute values |VCKMth| to the experimentally determined |VCKMexp| gives the best value for α=76.7 deg. and the value Jth=-2.18x10-5 for the Jarlskog invariant in good agreement with the experimental values. The agreement between |VCKMth| and |VCKMexp| is also very good with χ2=0.28

  4. Flavour symmetry breaking in the kaon parton distribution amplitude

    Chao Shi

    2014-11-01

    Full Text Available We compute the kaon's valence-quark (twist-two parton distribution amplitude (PDA by projecting its Poincaré-covariant Bethe–Salpeter wave-function onto the light-front. At a scale ζ=2 GeV, the PDA is a broad, concave and asymmetric function, whose peak is shifted 12–16% away from its position in QCD's conformal limit. These features are a clear expression of SU(3-flavour-symmetry breaking. They show that the heavier quark in the kaon carries more of the bound-state's momentum than the lighter quark and also that emergent phenomena in QCD modulate the magnitude of flavour-symmetry breaking: it is markedly smaller than one might expect based on the difference between light-quark current masses. Our results add to a body of evidence which indicates that at any energy scale accessible with existing or foreseeable facilities, a reliable guide to the interpretation of experiment requires the use of such nonperturbatively broadened PDAs in leading-order, leading-twist formulae for hard exclusive processes instead of the asymptotic PDA associated with QCD's conformal limit. We illustrate this via the ratio of kaon and pion electromagnetic form factors: using our nonperturbative PDAs in the appropriate formulae, FK/Fπ=1.23 at spacelike-Q2=17 GeV2, which compares satisfactorily with the value of 0.92(5 inferred in e+e− annihilation at s=17 GeV2.

  5. Flavour symmetry breaking in the kaon parton distribution amplitude

    Shi, Chao [Key Laboratory of Modern Acoustics, MOE, Institute of Acoustics, Nanjing University, Nanjing 210093 (China); Department of Physics, Nanjing University, Nanjing 210093 (China); Chang, Lei [CSSM, School of Chemistry and Physics University of Adelaide, Adelaide, SA 5005 (Australia); Roberts, Craig D. [Physics Division, Argonne National Laboratory, Argonne, IL 60439 (United States); Schmidt, Sebastian M. [Institute for Advanced Simulation, Forschungszentrum Jülich and JARA, D-52425 Jülich (Germany); Tandy, Peter C. [Center for Nuclear Research, Department of Physics, Kent State University, Kent, OH 44242 (United States); Zong, Hong-shi [Department of Physics, Nanjing University, Nanjing 210093 (China); State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, CAS, Beijing 100190 (China); Joint Center for Particle, Nuclear Physics and Cosmology, Nanjing 210093 (China)

    2014-11-10

    We compute the kaon's valence-quark (twist-two parton) distribution amplitude (PDA) by projecting its Poincaré-covariant Bethe–Salpeter wave-function onto the light-front. At a scale ζ=2 GeV, the PDA is a broad, concave and asymmetric function, whose peak is shifted 12–16% away from its position in QCD's conformal limit. These features are a clear expression of SU(3)-flavour-symmetry breaking. They show that the heavier quark in the kaon carries more of the bound-state's momentum than the lighter quark and also that emergent phenomena in QCD modulate the magnitude of flavour-symmetry breaking: it is markedly smaller than one might expect based on the difference between light-quark current masses. Our results add to a body of evidence which indicates that at any energy scale accessible with existing or foreseeable facilities, a reliable guide to the interpretation of experiment requires the use of such nonperturbatively broadened PDAs in leading-order, leading-twist formulae for hard exclusive processes instead of the asymptotic PDA associated with QCD's conformal limit. We illustrate this via the ratio of kaon and pion electromagnetic form factors: using our nonperturbative PDAs in the appropriate formulae, F{sub K}/F{sub π}=1.23 at spacelike-Q{sup 2}=17 GeV{sup 2}, which compares satisfactorily with the value of 0.92(5) inferred in e{sup +}e{sup −} annihilation at s=17 GeV{sup 2}.

  6. The effects of flavour symmetry breaking on hadron matrix elements

    By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between the strange and light quarks. We find the expansions to be highly constrained along a mass trajectory where the singlet quark mass is held constant, which proves beneficial for extrapolations of 2+1 flavour lattice data to the physical point. We investigate these effects numerically via a lattice calculation of the flavour-conserving and flavour-changing matrix elements of the vector and axial operators between octet baryon states.

  7. The effects of flavour symmetry breaking on hadron matrix elements

    Cooke, A.N.; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Pleiter, D. [Juelich Research Centre (Germany); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Division; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Zanotti, J.M. [Adelaide Univ. (Australia). School of Chemistry and Physics

    2012-12-15

    By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between the strange and light quarks. We find the expansions to be highly constrained along a mass trajectory where the singlet quark mass is held constant, which proves beneficial for extrapolations of 2+1 flavour lattice data to the physical point. We investigate these effects numerically via a lattice calculation of the flavour-conserving and flavour-changing matrix elements of the vector and axial operators between octet baryon states.

  8. The effects of flavour symmetry breaking on hadron matrix elements

    Cooke, A N; Nakamura, Y; Pleiter, D; Rakow, P E L; Schierholz, G; Zanotti, J M

    2012-01-01

    By considering a flavour expansion about the SU(3)-flavour symmetric point, we investigate how flavour-blindness constrains octet baryon matrix elements after SU(3) is broken by the mass difference between the strange and light quarks. We find the expansions to be highly constrained along a mass trajectory where the singlet quark mass is held constant, which proves beneficial for extrapolations of 2+1 flavour lattice data to the physical point. We investigate these effects numerically via a lattice calculation of the flavour-conserving and flavour-changing matrix elements of the vector and axial operators between octet baryon states.

  9. Gauge-Higgs unification with broken flavour symmetry

    We study a five-dimensional Gauge-Higgs unification model on the orbifold S1/Z2 based on the extended standard model (SM) gauge group SU(2)L x U(1)Y x SO(3)F. The group SO(3)F is treated as a chiral gauged flavour symmetry. Electroweak-, flavour- and Higgs interactions are unified in one single gauge group SU(7). The unified gauge group SU(7) is broken down to SU(2)L x U(1)Y x SO(3)F by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S1/Z2 is put on a lattice. This setting gives a well-defined staring point for renormalisation group (RG) transformations. As a result of the RG-flow, the bulk is integrated out and the extra dimension will consist of only two points: the orbifold fixed points. The model obtained this way is called an effective bilayered transverse lattice model. Parallel transporters (PT) in the extra dimension become nonunitary as a result of the blockspin transformations. In addition, a Higgs potential V(Φ) emerges naturally. The PTs can be written as a product eAyeηeAy of unitary factors eAy and a selfadjoint factor eη. The reduction 48 → 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2)L x U(1)Y x SO(3)F leads to three SU(2)L Higgs doublets: one for the first, one for the second and one for the third generation. Their zero modes serve as a substitute for the SM Higgs. When the extended SM gauge group SU(2)L x U(1)Y x SO(3)F is spontaneously broken down to U(1)em, an exponential gauge boson mass splitting occurs naturally. At a first step SU(2)L x U(1)Y x SO(3)F is broken to SU(2)L x U(1)Y by VEVs for the selfadjoint factor eη. This breaking leads to masses of flavour changing SO(3)F gauge bosons much above the compactification scale. Such a behaviour has no counterpart within the customary approximation scheme of an ordinary orbifold theory. This way tree-level flavour-changing-neutral-currents are

  10. Gauge-Higgs unification with broken flavour symmetry

    Olschewsky, M.

    2007-05-15

    We study a five-dimensional Gauge-Higgs unification model on the orbifold S{sup 1}/Z{sub 2} based on the extended standard model (SM) gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F}. The group SO(3){sub F} is treated as a chiral gauged flavour symmetry. Electroweak-, flavour- and Higgs interactions are unified in one single gauge group SU(7). The unified gauge group SU(7) is broken down to SU(2){sub L} x U(1){sub Y} x SO(3){sub F} by orbifolding and imposing Dirichlet and Neumann boundary conditions. The compactification scale of the theory is O(1) TeV. Furthermore, the orbifold S{sup 1}/Z{sub 2} is put on a lattice. This setting gives a well-defined staring point for renormalisation group (RG) transformations. As a result of the RG-flow, the bulk is integrated out and the extra dimension will consist of only two points: the orbifold fixed points. The model obtained this way is called an effective bilayered transverse lattice model. Parallel transporters (PT) in the extra dimension become nonunitary as a result of the blockspin transformations. In addition, a Higgs potential V({phi}) emerges naturally. The PTs can be written as a product e{sup A{sub y}}e{sup {eta}}e{sup A{sub y}} of unitary factors e{sup A{sub y}} and a selfadjoint factor e{sup {eta}}. The reduction 48 {yields} 35 + 6 + anti 6 + 1 of the adjoint representation of SU(7) with respect to SU(6) contains SU(2){sub L} x U(1){sub Y} x SO(3){sub F} leads to three SU(2){sub L} Higgs doublets: one for the first, one for the second and one for the third generation. Their zero modes serve as a substitute for the SM Higgs. When the extended SM gauge group SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is spontaneously broken down to U(1){sub em}, an exponential gauge boson mass splitting occurs naturally. At a first step SU(2){sub L} x U(1){sub Y} x SO(3){sub F} is broken to SU(2){sub L} x U(1){sub Y} by VEVs for the selfadjoint factor e{sup {eta}}. This breaking leads to masses of flavour changing SO(3){sub F

  11. A see-saw scenario of an $A_4$ flavour symmetric standard model

    Dinh, Dinh Nguyen; Văn, Phi Quang; Vân, Nguyen Thi Hông

    2016-01-01

    A see-saw scenario for an $A_4$ flavour symmetric standard model is presented. As before, the see-saw mechanism can be realized in several models of different types depending on different ways of neutrino mass generation corresponding to the introduction of new fields with different symmetry structures. In the present paper, a general desription of all these see-saw types is made with a more detailed investigation on type-I models. As within the original see-saw mechanism, the symmetry structure of the standard model fields decides the number and the symmetry structure of the new fields. In a model considered here, the scalar sector consists of three standard-model-Higgs-like iso-doublets ($SU_L(2)$-doublets) forming an $A_4$ triplet. The latter is a superposition of three mass-eigen states, one of which could be identified with the recently discovered Higgs boson. A possible relation to the still-deliberated 750 GeV diphoton resonance at the 13 TeV LHC collisions is also discussed. In the lepton sector, the ...

  12. Maximal conserved flavour symmetry in models with complementarity

    Models with complementarity for massless composite fermions are investigated. Through a study of 't Hooft's equations, we find a simple general criterion for the maximal conserved flavour group in terms of a given set of bi-fermion condensates in the Higgs picture. (orig.)

  13. Flavour symmetry breaking and tuning the strange quark mass for 2+1 quark flavours

    Bietenholz, W. [Universidad Autonoma de Mexico (Mexico). Inst. de Ciencias Nucleares; Bornyakov, V. [Institute for High Energy Physics, Protovino (Russian Federation); Institute of Theoretical and Experimental Physics, Moscow (Russian Federation); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

    2010-12-15

    QCD lattice simulations with 2+1 flavours typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass to its physical value and then the updown quark mass. An alternative method of tuning the quark masses is discussed here in which the singlet quark mass is kept fixed, which ensures that the kaon always has mass less than the physical kaon mass. Using group theory the possible quark mass polynomials for a Taylor expansion about the flavour symmetric line are found, which enables highly constrained fits to be used in the extrapolation of hadrons to the physical pion mass. Numerical results confirm the usefulness of this expansion and an extrapolation to the physical pion mass gives hadron mass values to within a few percent of their experimental values. (orig.)

  14. $A_4$ symmetry at colliders and in the universe

    Varzielas, Ivo de Medeiros; Maurer, Vinzenz

    2015-01-01

    Two puzzling facts of our time are the observed patterns in the fermion masses and mixings and the existence of non-baryonic dark matter, which are both often associated with extensions of the Standard Model at higher energy scales. In this paper, we consider a solution to these two problems with the flavour symmetry ${\\mathbb A}_4\\times {\\mathbb Z}_2\\times {\\mathbb Z}_2^\\prime$, in a model which has been shown before to explain large leptonic mixings with a specific texture. The model contains 3 generations of $SU(2)_L$-doublet scalar fields, arranged as an ${\\mathbb A}_4$-triplet, that spontaneously break the electroweak symmetry, and a "dark sector" of ${\\mathbb Z}_2$-odd fields, containing one Majorana neutrino and an ${\\mathbb A}_4$-triplet $SU(2)_L$-doublet scalar field, the lightest of which provides a candidate for dark matter. Concerning the ${\\mathbb Z}_2$-even scalar fields, compared to the Standard Model, we predict additional fields with masses at the electroweak scale. We therefore investigate p...

  15. Minimal flavour violation in the quark and lepton sector and the impact of extra dimensions on flavour changing neutral currents and electroweak symmetry breaking

    We study flavor-changing decays of hadrons and leptons and an extra-dimensional approach to electroweak symmetry breaking. Specifically we study the framework of Minimal Flavour Violation (MFV) as an explanation of the flavour problem. We discuss the impact of a specific extra-dimensional model of the MFV class on flavour changing neutral currents. We derive model-independent upper bounds on rare decays. -We discuss the extension of the MFV framework from the quark to the lepton sector and show how baryogenesis through leptogenesis can be achieved and examine if possible correlations with charged lepton flavour violation exist. We discuss the dynamical breaking of the electroweak symmetry in extra dimensions by unifying gauge and Higgs fields and we show that realistic models are possible once the extra dimension is strongly curved. (orig.)

  16. Minimal flavour violation in the quark and lepton sector and the impact of extra dimensions on flavour changing neutral currents and electroweak symmetry breaking

    Weiler, A.

    2007-01-16

    We study flavor-changing decays of hadrons and leptons and an extra-dimensional approach to electroweak symmetry breaking. Specifically we study the framework of Minimal Flavour Violation (MFV) as an explanation of the flavour problem. We discuss the impact of a specific extra-dimensional model of the MFV class on flavour changing neutral currents. We derive model-independent upper bounds on rare decays. -We discuss the extension of the MFV framework from the quark to the lepton sector and show how baryogenesis through leptogenesis can be achieved and examine if possible correlations with charged lepton flavour violation exist. We discuss the dynamical breaking of the electroweak symmetry in extra dimensions by unifying gauge and Higgs fields and we show that realistic models are possible once the extra dimension is strongly curved. (orig.)

  17. Lepton mixing predictions including Majorana phases from Δ(6n2) flavour symmetry and generalised CP

    Generalised CP transformations are the only known framework which allows to predict Majorana phases in a flavour model purely from symmetry. For the first time generalised CP transformations are investigated for an infinite series of finite groups, Δ(6n2)=(Zn×Zn)⋊S3. In direct models the mixing angles and Dirac CP phase are solely predicted from symmetry. The Δ(6n2) flavour symmetry provides many examples of viable predictions for mixing angles. For all groups the mixing matrix has a trimaximal middle column and the Dirac CP phase is 0 or π. The Majorana phases are predicted from residual flavour and CP symmetries where α21 can take several discrete values for each n and the Majorana phase α31 is a multiple of π. We discuss constraints on the groups and CP transformations from measurements of the neutrino mixing angles and from neutrinoless double-beta decay and find that predictions for mixing angles and all phases are accessible to experiments in the near future

  18. Minimal violation of flavour and custodial symmetries in a vectophobic Two-Higgs-Doublet-Model

    Tree-level accidental symmetries are known to play a fundamental role in the phenomenology of the Standard Model (SM) for electroweak interactions. So far, no significant deviations from the theory have been observed in precision, flavour and collider physics. Consequently, these global symmetries are expected to remain quite efficient in any attempt beyond the SM. Yet, they do not forbid rather unorthodox phenomena within the reach of current LHC experiments. This is illustrated with a vectophobic Two-Higgs-Doublet-Model (2HDM) where effects of a light, flavour-violating and custodian (pseudo)scalar might be observed in the Bs→μ+μ- decay rate and in the diphoton invariant mass spectrum at around 125 GeV.

  19. Predicting lepton mixing parameters including Majorana phases from Δ(6n2) flavour symmetry and generalised CP

    An important class of flavour groups that are subgroups of U(3) and that predict experimentally viable lepton mixing parameters including Majorana phases is the Δ(6n2) series. The most well-known member is Δ(24)=S4. I present results of several extensive studies of lepton mixing predictions obtained in models with a Δ(6n2) flavour group that preserve either the full Klein symmetry or a Z2 subgroup for neutrinos and can include a generalised CP symmetry. Predictions include mixing angles and Dirac CP phase generally; and if invariance under a generalised CP symmetry is included, also Majorana phases. For this, the interplay of flavour group and generalised CP symmetry has to be studied carefully. Furthermore, I present results for neutrinoless double-beta decay.

  20. The S{sub 3} flavour symmetry: Neutrino masses and mixings

    Gonzalez Canales, F. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico); Facultad de Ciencias de la Electronica, Benemerita Universidad Autonoma de Puebla (Mexico); Mondragon, A.; Mondragon, M. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico (Mexico)

    2013-04-02

    In this work, we discuss the neutrino masses and mixings as the realization of an S{sub 3} flavour permutational symmetry in two models, namely the Standard Model and an extension of the Standard Model with three Higgs doublets. In the S{sub 3} Standard Model, mass matrices of the same generic form are obtained for the neutrino and charged leptons when the S{sub 3} flavour symmetry is broken sequentially according to the chain S{sub 3L} x S{sub 3R} contains S{sub 3}{sup diag} contains S{sub 2}. In the minimal S{sub 3}-symmetric extension of the Standard Model, the S{sub 3} symmetry is left unbroken, and the concept of flavour is extended to the Higgs sector by introducing in the theory three Higgs fields which are SU(2) doublets. In both models, the mass matrices of the neutrinos and charged leptons are reparametrized in terms of their eigenvalues, and exact, explicit analytical expressions for the neutrino mixing angles as functions of the masses of neutrinos and charged leptons are obtained. In the case of the S{sub 3} Standard Model, from a {chi}{sup 2} fit of the theoretical expressions of the lepton mixing matrix to the values extracted from experiment, the numerical values of the neutrino mixing angles are obtained in excellent agreement with experimental data. In the S{sub 3} extension of the Standard Model, if two of the right handed neutrinos masses are degenerate, the reactor and atmospheric mixing angles are determined by the masses of the charged leptons, yielding {theta}{sub 23} in excellent agreement with experimental data, and {theta}{sub 13} different from zero but very small. If the masses of the three right handed neutrinos are assumed to be different, then it is possible to get {theta}{sub 13}also in very good agreement with experimental data. We also show the branching ratios of some selected flavour changing neutral currents (FCNC) process as well as the contribution of the exchange of a neutral flavour changing scalar to the anomaly of the

  1. Quark and lepton mass matrices with A4 family symmetry

    Realistic quark masses and mixing angles are obtained applying the successful A4 family symmetry for leptons, motivated by the quark-lepton assignments of SU(5). The A4 symmetry is suitable to give tri-bimaximal neutrino mixing matrix which is consistent with current experimental data. We study new scenario for the quark sector with the A4 symmetry. (author)

  2. Mass textures and wolfenstein parameters from breaking the flavour permutational symmetry

    Mondragon, A; Rivera, T. [Instituto de Fisica, Universidad Nacional Autonoma de Mexico,Mexico D.F. (Mexico); Rodriguez Jauregui, E. [Deutsches Elekronen-Synchrotron, Theory Group, Hamburg (Germany)

    2001-12-01

    We will give an overview of recent progress in the phenomenological study of quark mass matrices, quark flavour mixings and CP-violation with emphasis on the possibility of an underlying discrete, flavour permutational symmetry and its breaking, from which realistic models of mass generation could be built. The quark mixing angles and CP-violating phase, as well as the Wolfenstein parameters are given in terms of four quark mass ratios and only two parameters (Z{sup 1}/2, {phi}) characterizing the symmetry breaking pattern. Excellent agreement with all current experimental data is found. [Spanish] Daremos una visita panoramica del progreso reciente en el estudio fenomenologico de las matrices de masas y de mezclas del sabor de los quarks y la violacion de PC, con enfasis en la posibilidad de que, subyacentes al problema, se halle una simetria discreta, permutacional del sabor y su rompimiento a partir de las cuales se puedan construir modelos realistas de la generacion de las masas. Los angulos de mezcla de los quarks y la fase que viola CP, asi como los parametros de Wolfenstein se dan en terminos de cuatro razones de masas de los quarks y solamente dos parametros (Z{sup 1}/2, {phi}) que caracterizan el patron del rompimiento de la simetria. Los resultados se encuentran en excelente acuerdo con todos los datos experimentales mas recientes.

  3. Flavour blindness and patterns of flavour symmetry breaking in lattice simulations of up, down and strange quarks

    Bietenholz, W. [Univ. Autonoma de Mexico, Mexico City (Mexico). Inst. de Ciencias Nucleares; Bornyakov, V. [Inst. for High Energy Physics, Protovino (Russian Federation); Inst. for Theoretical and Experimental Physics, Moscow (Russian Federation); Goeckeler, M. [Regensburg Univ. (DE). Inst. fuer Theoretische Physik] (and others)

    2011-02-15

    QCD lattice simulations with 2+1 flavours typically start at rather large up-down and strange quark masses and extrapolate first the strange quark mass to its physical value and then the up-down quark mass. An alternative method of tuning the quark masses is discussed here in which the singlet quark mass is kept fixed, which ensures that the kaon always has mass less than the physical kaon mass. Using group theory the possible quark mass polynomials for a Taylor expansion about the flavour symmetric line are found, first for the general 1+1+1 flavour case and then for the 2+1 flavour case (when two quark flavours are mass degenerate). These enable highly constrained fits to be used in the extrapolation of hadrons to the physical pion mass. Numerical results for the 2+1 flavour case confirm the usefulness of this expansion and an extrapolation to the physical pion mass gives hadron mass values to within a few percent of their experimental values. Singlet quantities remain constant which allows the lattice spacing to be determined from hadron masses (without necessarily being at the physical point). Furthermore an extension of this programme to include partially quenched results is also given. (orig.)

  4. The 2-3 symmetry: Flavour Changing $b$, $\\tau$ Decays and Neutrino Mixing

    Datta, A; Datta, Alakabha; Donnell, Patrick J. O'

    2005-01-01

    The observed pattern of neutrino mixing may be the result of a 2-3($ \\mu- \\tau$) symmetry in the leptonic sector. We consider a two higgs doublet model with a 2-3 symmetry in the down type quark and the charged lepton sector. The breaking of the 2-3 symmetry by the strange quark mass and the muon mass leads to FCNC in the quark sector and the charged lepton sector that are suppressed by ${m_s \\over m_b}$ and ${m_{\\mu} \\over m_{\\tau}}$ in addition to the mass of the heavy higgs boson of the second higgs doublet. A higgs boson mass of $ m_H \\sim 900$ GeV can explain the deviation from standard model reported in several rare B decays. Predictions for other B decays are made and new CP phase is predicted in $B_{s}-{\\bar{B}_{s}}$ mixing. The lepton flavour violating decays $ \\tau \\to \\mu \\bar{l(q)} l(q)$ are below the experimental limits. The breaking of 2-3 symmetry in the lepton sector can lead to deviations of the atmospheric neutrino mixing angle from the maximal value by $ \\sim 2$ degrees.

  5. The breaking of the flavour permutational symmetry Mass textures and the CKM matrix

    Mondragón, A

    1999-01-01

    Different anzätse for the breaking of the flavour permutational symmetry acording to S_{L}(3) X S_{R}(3) \\supset S_{L}(2) X S_{R}(2) give different Hermitian mass matrices of the same modified Fritzsch type, which differ in the symmetry breaking pattern. In this work we obtain a clear and precise indication on the preferred symmetry breaking scheme from a fit of the predicted |V^{th}| to the experimentally determined absolute values of the elements of the CKM matrix. The preferred scheme leads to simple mass textures and allows us to compute the CKM mixing matrix, the Jarlskog invariant J, and the three inner angles of the unitarity triangle in terms of four quark mass ratios and only one free parameter: the CP violating phase \\Phi. Excellent agreement with the experimentally determined absolute values of the entries in the CKM matrix is obtained for \\Phi=90 degrees. The corresponding computed values of the Jarlskog invariant and the inner angles are J=3 x 10^{-5}, agreement with current data on CP violation...

  6. On spontaneous breaking of conformal symmetry by probe flavour D-branes

    We explore the possibilities of breaking conformal symmetry spontaneously by introducing flavour branes into conformal holographic backgrounds in the probe limit. A prototype model of such a mechanism is based on placing D7-D-bar7 configuration in the Klebanov-Witten conifold based model. In this paper we generalize this model. We conjecture on the required topology of the backgrounds and the corresponding probe brane embeddings. We identify several models that obey these requirements and admit spontaneous breaking of conformal invariance. These include type IIB conifold based examples, dual to defect field theories based on the conifold, and type IIA constructions based on the ABJM model. We identify the dilaton, the corresponding Goldstone boson, discuss its effective action and address the 'a-term'. We briefly discuss the relevance of these models to the pseudo dilaton

  7. Fermion mass hierarchies and flavour mixing from a minimal discrete symmetry

    Feruglio, Ferruccio; Lin, Yin

    2008-09-01

    We construct a simple model of fermion masses based on a spontaneously broken S×Z flavour group. At the leading order, in the neutrino sector S is broken down to a ν-ν parity subgroup that enforces a maximal atmospheric mixing angle and a vanishing θ. In the charged lepton sector the ν-ν parity is maximally broken and the resulting mass matrix is nearly diagonal. The charged lepton mass hierarchy is automatically reproduced by the S symmetry breaking parameter alone. A careful analysis shows that, after the inclusion of all relevant subleading effects, the model predicts θ=π/4+O(λc2) and θ=O(λc2), λ denoting the Cabibbo angle. A simple extension to the quark sector is also illustrated, where the mass spectrum and the mixing angles are naturally reproduced, with the exception of the mixing angle between the first two generations, that requires a small accidental enhancement.

  8. CP Violating Phase and Quark Mixing Angles from Flavour Permutational Symmetry-Breaking

    Mondragón, A

    2000-01-01

    The phase equivalence of the theoretical quark mixing matrix ${\\bf V}^{th}$ derived from the breaking of the flavour permutational symmetry and the phenomenological parametrizations ${\\bf V}^{PDG}$ and ${\\bf V}^{KM}$ is explicitly exhibited. From here, we derive exact explicit expressions for the three mixing angles and the CP violating phase of the two phenomenological parametrizations in terms of the quark mass ratios $(m_{u}/m_{t}, m_{c}/m_{t}, m_{d}/m_{b}, m_{s}/m_{b})$ and the parameters $Z^{*1/2}$ and $\\Phi^*$ characterizing the preferred symmetry breaking pattern. The computed values for the CP violating phase and the mixing angles of the standard parametrization advocated by the Particle Data Group are $\\delta^*_{13}=73.2^\\circ$, $\\sin\\theta^*_{12}=0.222$, $\\sin\\theta^*_{13}=0.0036$, and $\\sin\\theta^*_{23}=0.040$. The computed values of the CP-violating phase and the mixing angles of the Kobayashi-Maskawa parametrization are $\\delta^*_{KM}=96.4^\\circ$, $\\sin\\theta^*_{1}=0.2225$, $\\sin\\theta^*_{2}=0.03...

  9. The breaking of the flavour permutational symmetry Mass textures and the CKM matrix

    Mondragón, A

    1998-01-01

    Different ansaetze for the breaking of the flavour permutational symmetry according to S(3)L X S(3)R in S(2)L X S(2)R give different Hermitian mass matrices of the same modified Fritzsch type which are classified in terms of an auxiliary S(2) which is not a subgroup of S(3)L X S(3)R. A fit of the predicted theoretical Vckm to the experimentally determined absolute values of the elements of the CKM matrix gives a clear and precise indication on the preferred symmetry breaking scheme. The preferred scheme leads to simple mass textures and allows us to compute the CKM mixing matrix in terms of four quark mass ratios and only one free parameter: the CP violating phase Phi. Excellent agreement with the experimentally determined absolute values of the entries in the CKM matrix is obtained for Phi = 76.8 deg. The corresponding computed value of the Jarlskog invariant is J = -2.18 10^-5 in very good agreement with current data on CP violation in the neutral kaon-antikaon system.

  10. Phenomenological Tests of Supersymmetric $A_4$ Family Symmetry Model of Neutrino Mass

    Hirsch, M; Skadhauge, S; Valle, José W F; Del Moral, A V; 10.1103/PhysRevD.69.093006

    2004-01-01

    Recently Babu, Ma and Valle proposed a model of quark and lepton mixing based on $A_4$ symmetry. Within this model the lepton and slepton mixings are intimately related. We perform a numerical study in order to derive the slepton masses and mixings in agreement with present data from neutrino physics. We show that, starting from three-fold degeneracy of the neutrino masses at a high energy scale, a viable low energy neutrino mass matrix can indeed be obtained in agreement with constraints on lepton flavour violating $\\mu$ and $\\tau$ decays. The resulting slepton spectrum must necessarily include at least one mass below 200 GeV which can be produced at the LHC. The predictions for the absolute Majorana neutrino mass scale $m_0 \\geq 0.3$ eV ensure that the model will be tested by future cosmological tests and $\\beta\\beta_{0\

  11. CP and Lepton-Number Violation in GUT Neutrino Models with Abelian Flavour Symmetries

    Ellis, John; Gomez, Mario E.; Lola, Smaragda

    2006-01-01

    We study the possible magnitudes of CP and lepton-number-violating quantities in specific GUT models of massive neutrinos with different Abelian flavour groups, taking into account experimental constraints and requiring successful leptogenesis. We discuss SU(5) and flipped SU(5) models that are consistent with the present data on neutrino mixing and upper limits on the violations of charged-lepton flavours and explore their predictions for the CP-violating oscillation and Majorana phases. In ...

  12. The $750\\,\\text{GeV}$ diphoton resonance in the light of a 2HDM with $S_3$ flavour symmetry

    Hernández, A E Cárcamo; Schumacher, E

    2016-01-01

    Very recently we proposed a predictive 2 Higgs Doublet Model with $S_{3}$ flavour symmetry that successfully accounts for fermion masses and mixings. In this letter, motivated by the $750$ GeV Higgs diphoton resonance recently reported by the ATLAS and CMS collaborations, we modify this model by adding exotic top partners with electric charge $\\frac{5}{3}$. This simple modification enables our model to successfully account for the Higgs diphoton excess at $750\\,\\text{GeV}$ provided that the exotic quark masses are in the range $[1,1.8]$ TeV, for $O(1)$ exotic quark Yukawa couplings.

  13. Charge symmetry breaking in the A=4 hypernuclei

    Gazda, Daniel

    2016-01-01

    Charge symmetry breaking (CSB) in the $\\Lambda$-nucleon strong interaction generates a charge dependence of $\\Lambda$ separation energies in mirror hypernuclei, which in the case of the $A=4$ mirror hypernuclei $0^+$ ground states is sizable, $\\Delta B^{J=0}_{\\Lambda}\\equiv B^{J=0}_{\\Lambda} (_{\\Lambda}^4{\\rm He})-B^{J=0}_{\\Lambda}(_{\\Lambda}^4{\\rm H})=230\\pm 90$~keV, and of opposite sign to that induced by the Coulomb repulsion in light hypernuclei. Recent {\\it ab initio} calculations of the (\\lamb{4}{H}, \\lamb{4}{He}) mirror hypernuclei $0^+_{\\rm g.s.}$ and $1^+_{\\rm exc}$ levels have demonstrated that a $\\Lambda - \\Sigma^0$ mixing CSB model due to Dalitz and von Hippel (1964) is capable of reproducing this large value of $\\Delta B^{J=0}_{\\Lambda}$. These calculations are discussed here with emphasis placed on the leading-order $\\chi$EFT hyperon-nucleon strong-interaction Bonn-J\\"{u}lich model used and the no-core shell-model calculational scheme applied. The role of one-pion exchange in producing sizable C...

  14. The discrete family symmetry as a possible solution to the flavour problem

    Dziewit, Bartosz; Richter, Monika; Zając, Sebastian; Zrałek, Marek

    2016-01-01

    In order to explain the fermions masses and mixing parameters appearing in the lepton sector of the Standard Model, one proposes the extension of its symmetry. A discrete, non-abelian subgroup of $U(3)$ is added to the gauge group $SU(3)_{C}\\times SU(2)_{L}\\times U(1)_{Y}$ . Apart from that, one assumes the existence of one extra Higgs doublet. This article focuses mainly on the mathematical theorems and computational techniques which brought us to the results.

  15. Flavon-induced connections between lepton flavour mixing and charged lepton flavour violation processes

    Pascoli, Silvia

    2016-01-01

    In leptonic flavour models with discrete flavour symmetries, couplings between flavons and leptons can result in special flavour structures after they gain vacuum expectation values. At the same time, they can also contribute to the other lepton-flavour-violating processes. We study the flavon-induced LFV 3-body charged lepton decays and radiative decays and we take as example the $A_4$ discrete symmetry. In $A_4$ models, a $Z_3$ residual symmetry roughly holds in the charged lepton sector for the realisation of tri-bimaximal mixing at leading order. The only processes allowed by this symmetry are $\\tau^-\\to \\mu^+ e^- e^-, e^+ \\mu^- \\mu^-$, and the other 3-body and all radiative decays are suppressed by small $Z_3$-breaking effects. These processes also depend on the representation the flavon is in, whether pseudo-real (case i) or complex (case ii). We calculate the decay rates for all processes for each case and derive their strong connection with lepton flavour mixing. In case i, sum rules for the branching...

  16. Generalized permutation symmetry and the flavour problem in SU(2)sub(L)xU(1)

    A generalized permutation group is introduced as a possible horizontal symmetry for SU(2)sub(L)xU(1) gauge theories. It leads to the unique two generation quark mass matrices with a correct prediction for the Cabibbo angle. For three generations the model exhibits spontaneous CP violation, correlates the Kobayashi-Maskawa mixing parameters s1 and s3 and predicts an upper bound for the running top quark mass of approximately 45 GeV. The hierarchy of generations is due to a hierarchy of vacuum expectation values rather than of Yukawa coupling constants. (orig.)

  17. Mass Matrix Model Broken From A4 To 2 $\\leftrightarrow$ 3 Symmetry

    Fukuyama, Takeshi

    2008-01-01

    2$\\leftrightarrow$3 symmetry is realized by the breaking from alterating group of degree 4 ($A4$) symmetry. $A4$ explains why the generation number is three. However the mass matrices are realized in the form of the breaking to $2\\leftrightarrow 3$ symmetry $\\times Z_3$, which leads us to $2\\leftrightarrow 3$ symmetric mass matrix with vanishing (1,1) component. Thus the $3\\times 3$ mass matrix model with $2\\leftrightarrow 3$ symmetry and vanishing (1,1) component has the group theoretical background as the symmetry in GUT model.

  18. Non-minimally flavour violating dark matter

    Blanke, Monika

    2015-01-01

    Flavour symmetries provide an appealing mechanism to stabilize the dark matter particle. I present a simple model of quark flavoured dark matter that goes beyond the framework of minimal flavour violation. I discuss the phenomenological implications for direct and indirect dark matter detection experiments, high energy collider searches as well as flavour violating precision data.

  19. Flavour reformulation and flavour stability

    Yang, Ni

    2012-01-01

    ABSTRACT This project addressed two areas in the flavour industry – flavour reformulation required as a consequence of ingredient changes and flavour stability in solid food products. The aim of the flavour reformulation study was to evaluate both instrumental and modelling approaches to reformulate commercial flavourings for food products of different fat contents. A strawberry flavouring was chosen, which delivered an acceptable flavour in pectin jelly (0% fat) but did not perform so...

  20. The CP violating phase $\\delta_{13}$ and the quark mixing angles $\\theta_{13}, \\theta_{23}$ and $\\theta_{12}$ from flavour permutational symmetry breaking

    Mondragón, A

    2000-01-01

    We show that the theoretical mixing matrix V^{th} derived from the breaking of the flavour permutational symmetry and the standard parametrization V^{PDG} advocated by the Particle Data Group are equivalent, up to a redefinition of the unobservable phases of the quark fields in the mass representation. From here, we derive exact explicit expressions for the three mixing angles in terms of the quark mass ratios (m_{u}/m_{t}, m_{c}/m_{t}, m_{d}/m_{b}, m_{s}/m_{b}) and the parameters Z^{*1/2} and \\Phi* characterizing the preferred symmetry breaking pattern. The predicted values for the CP violating phase and the mixing angles are: \\delta*_{13}=72 degrees, \\sin(\\theta*_{12})=0.220817, almost exactly with the central values of the experimentally determined quantities.

  1. Non-zero $\\theta_{13}$ and leptonic CP phase with $A_4$ Symmetry

    M., Sruthilaya

    2016-01-01

    We consider a model based on $A_4$ symmetry to explain lepton mixing. The spontaneous symmetry breaking of $A_4$ symmetry leads to a co-bimaximal mixing matrix. We add a $Z_2\\times Z_2$ invariant perturbation in the charged lepton sector to make the predicted mixing angles compatible with the recent results from neutrino oscillation experiments. We find that the mixing angles obtained in this approach come well within the $3\\sigma$ ranges of their experimental values. We also study the implications of this model on the other phenomenological observables, such as CP violating phase, Jarlskog invariant and the effective Majorana mass $|M_{ee}|$.

  2. Phenomenological aspects of flavoured dark matter

    Blanke, Monika

    2015-01-01

    Flavour symmetries in the dark sector are a theoretically motivated and phenomenologically appealing concept. The dark matter particle can be stabilised with the help of flavour symmetries, without the need to introduce an additional discrete symmetry by hand. Apart from the usual searches in direct and indirect detection experiments and high energy colliders, flavoured dark matter generally also gives rise to new flavour violating interactions leading to interesting signatures in rare meson decays. This proceedings article reviews a simplified model of flavoured dark matter in which the dark matter coupling to quarks constitutes a new source of flavour violation, so that the model goes beyond Minimal Flavour Violation. Particular emphasis is put on the discussion of its phenomenological implications in flavour, collider and direct detection experiments.

  3. The neutron anomaly in the gamma N --> eta N cross section through the looking glass of the flavour SU(3) symmetry

    Boika, T; Polyakov, M V

    2014-01-01

    We study the implications of the flavour SU(3) symmetry for various interpretations of the neutron anomaly in the $\\gamma N\\to\\eta N$ cross section. We show that the explanation of the neutron anomaly due to interference of known N(1535) and N(1650) resonances implies that N(1650) resonance should have a huge coupling to $\\phi$-meson -- at least 5 times larger than the corresponding $\\rho^0$ coupling. In terms of quark degrees of freedom this means that the well-known N(1650) resonance must be a "cryptoexotic pentaquark"-- its wave function should contain predominantly an $s\\bar s$ component. It turns out that the "conventional" interpretation of the neutron anomaly by the interference of known resonances metamorphoses into unconventional physics picture of N(1650).

  4. $A_4$ and CP symmetry and a model with maximal CP violation

    Li, Cai-Chang; Ding, Gui-Jun

    2016-01-01

    We study a second CP symmetry compatible with the $A_4$ flavor group, which interchanges the representations $\\mathbf{1}'$ and $\\mathbf{1}"$. We analyze the lepton mixing patterns arising from the $A_4$ and CP symmetry broken to residual subgroups $Z_3$ and $Z_2\\times CP$ in the charged lepton and neutrino sectors respectively. One phenomenologically viable mixing pattern is found, and it predicts maximal atmospheric mixing angle as well as maximal Dirac CP phase, trivial Majorana phase and the correlation $\\sin^2\\theta_{12}\\cos^2\\theta_{13}=1/3$. We construct a concrete model based on the $A_4$ and CP symmetry, the above interesting mixing pattern is achieved, the observed charged lepton mass hierarchy is reproduced, and the reactor mixing angle $\\theta_{13}$ is of the correct order.

  5. Flavoured Dark Matter Beyond MFV

    Blanke, Monika

    2014-01-01

    We review a model of quark flavoured dark matter with new flavour violating interactions. This simplified model describes Dirac fermionic dark matter that is charged under a new U(3) flavour symmetry and couples to right-handed down quarks via a scalar mediator. The corresponding coupling matrix is assumed to be the only new source of flavour violation, which we refer to as the Dark Minimal Flavour Violation (DMFV) hypothesis. This ansatz ensures the stability of dark matter. We discuss the phenomenology of the simplest DMFV model in flavour violating observables, LHC searches, and direct dark matter detection experiments. Especially interesting is the non-trivial interplay between the constraints from the different sectors.

  6. New and trivial C P symmetry for extended A4 flavor

    Nishi, C. C.

    2016-05-01

    The combination of νμ-ντ exchange together with C P conjugation in the neutrino sector (known as CPμ τ symmetry or μ τ reflection) is known to predict the viable pattern θ23=4 5 ° , a maximal Dirac C P phase, and trivial Majorana phases. We implement such a C P symmetry as a new C P symmetry in theories with A4 flavor. The implementation in a complete renormalizable model leads to a new form for the neutrino mass matrix that leads to further predictions: a normal hierarchical spectrum with a lightest mass and mβ β (0 ν 2 β ) of only few meV, and either ν1 or ν2 has opposite C P parity. An approximate Lμ-Lτ symmetry arises naturally and controls the flavor structure of the model. The light neutrino masses are generated by the extended seesaw mechanism with six right-handed neutrinos (RHNs). The requirement of negligible one-loop corrections to light neutrino masses, the validity of the extended seesaw approximation, and not too long-lived beyond-the-Standard-Model states to comply with big bang nucleosynthesis essentially restricts the parameters of the model to a small region: three relatively light right-handed neutrinos at the GeV scale, heavier neutrinos at the electroweak scale, and Yukawa couplings smaller than the electron Yukawa. Such small Yukawa couplings render these RHNs unobservable in terrestrial experiments.

  7. The role of flavon cross couplings in leptonic flavour mixing

    Pascoli, Silvia

    2016-01-01

    In models with discrete flavour symmetries, flavons are critical to realise specific flavour structures. Leptonic flavour mixing originates from the misalignment of flavon vacuum expectation values which respect different residual symmetries in the charged lepton and neutrino sectors. Flavon cross couplings are usually forbidden, in order to protect these symmetries. Contrary to this approach, we show that cross couplings can play a key role and give raise to necessary corrections to flavour-mixing patterns, including a non-zero value for the reactor angle and CP violation. For definiteness, we present two models based on $A_4$. In the first model, all flavons are assumed to be real or pseudo-real, with 7 real degrees of freedom in the flavon sector in total. A sizable reactor angle associated with nearly maximal CP violation is achieved, and, as both originate from the same cross coupling, a sum rule results with a precise prediction for the value of the Dirac CP-violating phase. In the second model, the fla...

  8. Neutrino and Changed Lepton Flavour Today

    Alonso, R; Hernandez, D; Merlo, L; Rigolin, S

    2013-01-01

    Flavour physics is a priceless window on physics beyond the Standard Model. In particular, flavour violation in the lepton sector looks very promising, as high precision measurements are prospected in future experiments investigating on $\\mu\\rightarrow e$ conversion in atomic nuclei: the predictions for this observable are analysed in the context of the type I Seesaw mechanism. Furthermore, new ideas to explain the Flavour Puzzle recently appeared, mainly based on a possible dynamical origin of the Yukawa couplings and on flavour symmetries. The focus of this proceeding will be set on the Minimal Flavour Violation ansatz and on the role of the neutrino Majorana character: when an $O(2)_{N}$ flavour symmetry acts on the right-handed neutrino sector, the minimum of the scalar potential allows for large mixing angles -in contrast to the simplest quark case- and predicts a maximal Majorana phase. This leads to a strong correlation between neutrino mass hierarchy and mixing pattern.

  9. Meat flavour

    For the consumer, meat is characterized by a certain number of organoleptic qualities; among them, flavour -that is to say the association of both odour and taste- plays a leading part. This property is based upon a great number of chemical components: some volatile components are responsible for the aroma and some non-volatile ones for the taste. These substances are either made or released during the heating of the meat on account of components called precursors which are produced during the aging of the meat. The two main reactions which preside over the elaboration of flavour are: the Maillard's reaction and the autooxidation reactions. Meat flavour is associated with the animal characteristics; it is influenced by the ante- and post mortem treatments as well as by the technological treatments for storing it. The use of synthetical flavours is to be considered as possible in the future

  10. Spontaneous CP violation and neutral flavour conservation

    The conditions for one-loop stability of neutral flavour conservation in SU(2)LxU(1) models with spontaneous CP violation are analysed. In addition to previously known cases there is an essentially unique two-generation model with two Higgs doublets where neutral flavour conservation is guaranteed to all orders by a non-standard CP symmetry. (orig.)

  11. Two-Higgs-doublet models with Minimal Flavour Violation

    Carlucci, Maria Valentina

    2010-01-01

    The tree-level flavour-changing neutral currents in the two-Higgs-doublet models can be suppressed by protecting the breaking of either flavour or flavour-blind symmetries, but only the first choice, implemented by the application of the Minimal Flavour Violation hypothesis, is stable under quantum corrections. Moreover, a two-Higgs-doublet model with Minimal Flavour Violation enriched with flavour-blind phases can explain the anomalies recently found in the Delta F = 2 transitions, namely the large CP-violating phase in B_s mixing and the tension between epsilon_K and S_\\psi_K.

  12. Compatibility of theta13 and the Type I Seesaw Model with A4 Symmetry

    Chen, Mu-Chun; O'Bryan, Jon-Michael; Wijangco, Alexander M; Yu, Felix

    2012-01-01

    We derive formulae for neutrino masses and mixing angles in a type I seesaw framework with an underlying A4 flavor symmetry. In particular, the Majorana neutrino mass matrix includes contributions from an A4 triplet, 1, 1', and 1" flavon fields. Using these formulae, we constrain the general A4 parameter space using the updated global fits on neutrino mixing angles and mass squared differences, including results from the Daya Bay and RENO experiments, and we find predictive relations among the mixing parameters for certain choices of the triplet vacuum expectation value. In the normal hierarchy case, sizable deviation from maximal atmospheric mixing is predicted, and such deviation is strongly correlated with the value of theta13 in the range of ~ (8-10) degrees. On the other hand, such deviation is negligible and insensitive to theta13 in the inverted mass hierarchy case. We also show expectations for the Dirac CP phase resulting from the parameter scan. Future refined measurements of neutrino mixing angles ...

  13. Flavour Behavior

    奎斯特国际有限公司

    2004-01-01

    @@ A good flavour must taste realistic and natural as well as performing under tough conditions, says Mairi Coia. In conjunction with texture or mouthfeel, flavour is the most important aspect of food. It is the one thing can bring consumers back to a product again and again - or not, as the case may be. In short, taste is the number one attribute in food and that is why the global fiavour business is worth A5 billion every year as manufacturers strive to make food taste better and fresher for longer.

  14. Heavy flavours

    Buras, Andrzej J

    1992-01-01

    This volume is a collection of review articles on the most outstanding topics in heavy flavour physics. All the authors have made significant contributions to this field. The book reviews in detail the theoretical structure of heavy flavour physics within the Standard Model and its confrontation with existing experimental data. The physics of the top quark and of the Higgs play an important role in this volume. Beginning with radiative electroweak corrections and their impressive tests at LEP and hadron colliders, the book summarizes the present status of quark mixing, CP violation and rare de

  15. Heavy flavours

    Buras, Andrzej J

    1998-01-01

    This volume is a collection of review articles on the most outstanding topics in heavy flavour physics. All the authors have made significant contributions to this field. The book reviews in detail the theoretical structure of heavy flavour physics and confronts the Standard Model and some of its extensions with existing experimental data.This new edition covers new trends and ideas and includes the latest experimental information. Compared to the previous edition interesting new activities are included and some of the key contributions are updated. Particular attention is paid to the discover

  16. Toward minimal renormalizable SUSY SU(5) Grand Unified Model with tribimaximal mixing from A4 Flavor symmetry

    Ciafaloni, Paolo; Torrente-Lujan, Emilio; Urbano, Alfredo

    2009-01-01

    We address the problem of rationalizing the pattern of fermion masses and mixings by adding a nonabelian flavor symmetry in a grand unified framework. With this purpose, we include an A4 flavor symmetry into a unified renormalizable SUSY GUT SU(5) model. With the help of the "Type II Seesaw" mechanism we are able to obtain the pattern of observed neutrino mixings in a natural way, through the so called tribimaximal matrix.

  17. Flavour Visions

    Buras, Andrzej J

    2011-01-01

    This decade will allow to improve the resolution of the short distance scales by at least an order of magnitude, extending the picture of fundamental physics down to scales $5\\cdot 10^{-20}$m with the help of the LHC. Further resolution down to scales as short as $10^{-21}$m should be possible with the help of high precision experiments in which flavour violating processes will play a prominent role. Will this increase in resolution allow us to see new particles (new animalcula) similarly to what Antoni van Leeuvenhoek saw by discovering bacteria in 1676? The basic question for particle physics is how these new animalcula will look like and which difficulties of the Standard Model (SM) they will help us to solve and which new puzzles and problems they will bring with them. I will describe what role flavour physics will play in these exciting times provided this new world is animalculated.

  18. Neutrino masses and tribimaximal mixing in Minimal renormalizable SUSY SU(5) Grand Unified Model with A4 Flavor symmetry

    Ciafaloni, Paolo; Torrente-Lujan, Emilio; Urbano, Alfredo

    2009-01-01

    We analyze all possible extensions of the recently proposed minimal renormalizable SUSY SU(5) grand unified model with the inclusion of an additional A4 flavor symmetry. We find that there are 5 possible Cases but only one of them is phenomenologically interesting. We develop in detail such Case and we show how the fermion masses and mixing angles come out. As prediction we obtain the neutrino masses of order of 0.1 eV with an inverted hierarchy.

  19. Ab initio Calculations of Charge Symmetry Breaking in the A =4 Hypernuclei

    Gazda, Daniel; Gal, Avraham

    2016-03-01

    We report on ab initio no-core shell model calculations of the mirror Λ hypernuclei H4Λ and He4Λ , using the Bonn-Jülich leading-order chiral effective field theory hyperon-nucleon potentials plus a charge symmetry breaking Λ -Σ0 mixing vertex. In addition to reproducing rather well the 0g.s . + and 1exc+ binding energies, these four-body calculations demonstrate for the first time that the observed charge symmetry breaking splitting of mirror levels, reaching hundreds of keV for 0g.s . +, can be reproduced using realistic theoretical interaction models, although with a non-negligible momentum cutoff dependence. Our results are discussed in relation to recent measurements of the H4Λ(0g.s . +) binding energy at the Mainz Microtron [A. Esser et al. (A1 Collaboration), Phys. Rev. Lett. 114, 232501 (2015)] and the He4Λ(1exc+) excitation energy [T.O. Yamamoto et al. (J-PARC E13 Collaboration), Phys. Rev. Lett. 115, 222501 (2015)].

  20. Ab-initio calculations of charge symmetry breaking in the A=4 hypernuclei

    Gazda, Daniel

    2015-01-01

    We report on ab-initio NCSM calculations of the A=4 mirror Lambda hypernuclei Lambda-4H and Lambda-4He, using the Bonn-Juelich LO chiral EFT YN potentials plus a CSB Lambda0--Sigma0 mixing vertex. In addition to reproducing rather well the 0+ (g.s.) and 1+ (exc.) binding energies, these four-body calculations demonstrate for the first time that the observed CSB splitting of mirror levels, reaching hundreds of keV for 0+ (g.s.), can be reproduced using realistic theoretical interaction models, although with a non-negligible momentum cutoff dependence. Our results are discussed in relation to recent measurements of the Lambda-4H (0+ g.s.) binding energy [MAMI A1 Collaboration, Phys. Rev. Lett. 114, 232501 (2015)] and the Lambda-4He (1+ exc.) excitation energy [J-PARC E13 Collaboration, Phys. Rev. Lett. 115, 222501 (2015)].

  1. Deviation from tri-bimaximal mixing and flavor symmetry breaking in a seesaw type A4 model

    We have studied the contribution of higher order corrections of the flavor symmetry breaking in the A4 seesaw model with the supersymmetry. Taking account of possible higher dimensional mass operators, we predict the deviation from the tri-bimaximal lepton mixing for both normal hierarchy and inverted hierarchy of neutrino masses. We have found that the value of sin22θ23 is larger than 0.96 and the upper bound of sin2θ13 is 0.01. We have also examined the flavor changing neutral current of leptons from the soft SUSY breaking in slepton masses and A-terms within the framework of supergravity theory. Those magnitudes are enough suppressed to be consistent with experimental constraints.

  2. A to Z of Flavour with Pati-Salam

    King, Stephen F.

    2014-08-01

    We propose an elegant theory of flavour based on A 4 × Z 5 family symmetry with Pati-Salam unification which provides an excellent description of quark and lepton masses, mixing and CP violation. The A 4 symmetry unifies the left-handed families and its vacuum alignment determines the columns of Yukawa matrices. The Z 5 symmetry distinguishes the right-handed families and its breaking controls CP violation in both the quark and lepton sectors. The Pati-Salam symmetry relates the quark and lepton Yukawa matrices, with Y u = Y ν and Y d ~ Y e . Using the see-saw mechanism with very hierarchical right-handed neutrinos and CSD4 vacuum alignment, the model predicts the entire PMNS mixing matrix and gives a Cabibbo angle θ C ≈ 1/4. In particular, for a discrete choice of Z 5 phases, it predicts maximal atmospheric mixing, θ {23/ l } = 45° ± 0.5° and leptonic CP violating phase δ l = 260° ± 5°. The reactor angle prediction is θ {13/ l } = 9° ± 0.5°, while the solar angle is 34° ≳ θ {12/ l } ≳ 31°, for a lightest neutrino mass in the range 0 ≲ m 1 ≲ 0.5 meV, corresponding to a normal neutrino mass hierarchy and a very small rate for neutrinoless double beta decay.

  3. Lepton flavour violation in composite Higgs models

    Feruglio, Ferruccio, E-mail: feruglio@pd.infn.it; Paradisi, Paride, E-mail: paride.paradisi@pd.infn.it [Sezione di Padova, Dipartimento di Fisica e Astronomia ‘G. Galilei’, INFN, Università di Padova, Via Marzolo 8, 35131, Padua (Italy); Pattori, Andrea, E-mail: pattori@physik.uzh.ch [Physik-Institut, Universität Zürich, 8057, Zurich (Switzerland)

    2015-12-08

    We discuss in detail the constraints on the partial compositeness coming from flavour and CP violation in the leptonic sector. In the first part we present a formulation of partial compositeness in terms of a flavour symmetry group and a set of spurions, whose background values specify the symmetry breaking pattern. In such a framework we construct the complete set of dimension-six operators describing lepton flavour violation and CP violation. By exploiting the existing bounds, we derive limits on the compositeness scale in different scenarios, characterised by increasing restrictions on the spurion properties. We confirm that in the most general case the compositeness scale should lie well above 10 TeV. However, if in the composite sector the mass parameters and Yukawa couplings are universal, such a bound can be significantly lowered, without necessarily reproducing the case of minimal flavour violation. The most sensitive processes are decays of charged leptons either of radiative type or into three charged leptons, μ→e conversion in nuclei and the electric dipole moment of the electron. In the second part we explicitly compute the Wilson coefficients of the relevant dimension-six operators in the so-called two-site model, embodying the symmetry breaking pattern discussed in our first part, and we compare the results with those of the general spurion analysis.

  4. Lepton flavour violation in composite Higgs models

    Feruglio, Ferruccio; Paradisi, Paride [Universita di Padova, Dipartimento di Fisica e Astronomia ' G. Galilei' , Padua (Italy); INFN, Padua (Italy); Pattori, Andrea [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland)

    2015-12-15

    We discuss in detail the constraints on the partial compositeness coming from flavour and CP violation in the leptonic sector. In the first part we present a formulation of partial compositeness in terms of a flavour symmetry group and a set of spurions, whose background values specify the symmetry breaking pattern. In such a framework we construct the complete set of dimension-six operators describing lepton flavour violation and CP violation. By exploiting the existing bounds, we derive limits on the compositeness scale in different scenarios, characterised by increasing restrictions on the spurion properties. We confirm that in the most general case the compositeness scale should lie well above 10 TeV. However, if in the composite sector the mass parameters and Yukawa couplings are universal, such a bound can be significantly lowered, without necessarily reproducing the case of minimal flavour violation. The most sensitive processes are decays of charged leptons either of radiative type or into three charged leptons, μ → e conversion in nuclei and the electric dipole moment of the electron. In the second part we explicitly compute the Wilson coefficients of the relevant dimension-six operators in the so-called two-site model, embodying the symmetry breaking pattern discussed in our first part, and we compare the results with those of the general spurion analysis. (orig.) 7.

  5. New Physics in the Flavour Sector

    Crivellin, Andreas

    2016-01-01

    Several experiments observed deviations from the Standard Model (SM) in the flavour sector: LHCb found a $4-5\\,\\sigma$ discrepancy compared to the SM in $b\\to s\\mu^+\\mu^-$ transitions (recently supported by an Belle analysis) and CMS reported a non-zero measurement of $h\\to\\mu\\tau$ with a significance of $2.4\\,\\sigma$. Furthermore, BELLE, BABAR and LHCb founds hints for the violation of flavour universality in $B\\to D^{(*)}\\tau\

  6. Embedding A4 into SU(3)xU(1) flavor symmetry: Large neutrino mixing and fermion mass hierarchy in SO(10) GUT

    Bazzocchi, F; Picariello, M; Torrente-Lujan, E

    2008-01-01

    We present a common explanation of the fermion mass hierarchy and the large lepton mixing angles in the context of a grand unified flavor and gauge theory (GUTF). Our starting point is a SU(3)xU(1) flavor symmetry and a SO(10) GUT, a basic ingredient of our theory which plays a major role is that two different breaking pattern of the flavor symmetry are at work. On one side, the dynamical breaking of SU(3)xU(1) flavor symmetry into U(2)xZ_3 explains why one family is much heavier than the others. On the other side, an explicit symmetry breaking of SU(3) into a discrete flavor symmetry leads to the observed tribimaximal mixing for the leptons. We write an explicit model where this discrete symmetry group is A4. Naturalness of the charged fermion mass hierarchy appears as a consequence of the continuous SU(3) flavor symmetry. Moreover, the same discrete A4-GUT invariant operators are the root of the large lepton mixing, small Cabibbo angle, and neutrino masses.

  7. Minimal flavour violation and neutrino masses without R-parity

    Arcadi, G.; Di Luzio, L.; Nardecchia, M.

    2012-01-01

    symmetry breaking all the couplings of the superpotential including the R-parity violating ones. If R-parity violation is responsible for neutrino masses, our setup can be seen as an extension of MFV to the lepton sector. We analyze two patterns based on the non-abelian flavour symmetries SU(3)(4) circle...

  8. Dark matter and observable Lepton Flavour Violation

    Heurtier, Lucien; Teresi, Daniele

    2016-01-01

    Seesaw models with leptonic symmetries allow right-handed (RH) neutrino masses at the electroweak scale, or even lower, at the same time having large Yukawa couplings with the Standard Model leptons, thus yielding observable effects at current or near-future lepton-flavour-violation (LFV) experiments. These models have been previously considered also in connection to low-scale leptogenesis, but the combination of observable LFV and successful leptogenesis has appeared to be difficult to achie...

  9. Flavour Tagging at LHCb

    Grabalosa Gandara, M

    2009-01-01

    To do precise CP violation measurements, the most possible accurate knowledge of the flavour at production of the reconstructed B meson is required. This poster summarizes the flavour tagging performances for the LHCb experiment. We use same side an opposite side algorithms to establish wheter the meson contained a b or a b\\bar quark. The final decision is obtained through a combination of several methods. The use of control channels, decays to a flavour specific final state, will allow to determine the wrong tag fraction \\omega (the probability of a tag to be wrong), which can be used as input for the determination of CKM unitary triangle angles.

  10. Heavy flavour in ALICE

    Pillot, Philippe

    2008-01-01

    Open heavy flavours and heavy quarkonium states are expected to provide essential informa- tion on the properties of the strongly interacting system fo rmed in the early stages of heavy-ion collisions at very high energy density. Such probes are espe cially promising at LHC energies where heavy quarks (both c and b) are copiously produced. The ALICE detector shall measure the production of open heavy flavours and heavy quarkonium st ates in both proton-proton and heavy-ion collisions at the LHC. The expected performances of ALICE for heavy flavour physics is discussed based on the results of simulation studies on a s election of benchmark channels

  11. Supersymmetric Radiative Flavour

    Conlon, Joseph P.; Pedro, Francisco G.

    2011-01-01

    We examine possibilities for the radiative generation of the Yukawa couplings and flavour structure in supersymmetric models in the supersymmetric phase. Not withstanding the non-renormalisation of the Wilsonian superpotential, this can occur through the 2-loop vertex renormalisation of the physical 1PI couplings. We describe this effect and construct models in which this occurs. For models attempting to reproduce the full flavour structure of the Standard Model, we analyse the tension betwee...

  12. Two approaches towards the flavour puzzle. Dynamical minimal flavour violation and warped extra dimensions

    Albrecht, Michaela E.

    2010-08-16

    The minimal-flavour-violating (MFV) hypothesis considers the Standard Model (SM) Yukawa matrices as the only source of flavour violation. In this work, we promote their entries to dynamical scalar spurion fields, using an effective field theory approach, such that the maximal flavour symmetry (FS) of the SM gauge sector is formally restored at high energy scales. The non-vanishing vacuum expectation values of the spurions induce a sequence of FS breaking and generate the observed hierarchy in the SM quark masses and mixings. The fact that there exists no explanation for it in the SM is known as the flavour puzzle. Gauging the non-abelian subgroup of the spontaneously broken FS, we interpret the associated Goldstone bosons as the longitudinal degrees of freedom of the corresponding massive gauge bosons. Integrating out the heavy Higgs modes in the Yukawa spurions leads directly to flavour-changing neutral currents (FCNCs) at tree level. The coefficients of the effective four-quark operators, resulting from the exchange of heavy flavoured gauge bosons, strictly follow the MFV principle. On the other hand, the Goldstone bosons associated with the global abelian symmetry group behave as weakly coupled axions which can be used to solve the strong CP problem within a modified Peccei-Quinn formalism. Models with a warped fifth dimension contain five-dimensional (5D) fermion bulk mass matrices in addition to their 5D Yukawa matrices, which thus represent an additional source of flavour violation beyond MFV. They can address the flavour puzzle since their eigenvalues allow for a different localisation of the fermion zero mode profiles along the extra dimension which leads to a hierarchy in the effective four-dimensional (4D) Yukawa matrices. At the same time, the fermion splitting introduces non-universal fermion couplings to Kaluza-Klein (KK) gauge boson modes, inducing tree-level FCNCs. Within a Randall-Sundrum model with custodial protection (RSc model) we carefully work

  13. Two approaches towards the flavour puzzle. Dynamical minimal flavour violation and warped extra dimensions

    The minimal-flavour-violating (MFV) hypothesis considers the Standard Model (SM) Yukawa matrices as the only source of flavour violation. In this work, we promote their entries to dynamical scalar spurion fields, using an effective field theory approach, such that the maximal flavour symmetry (FS) of the SM gauge sector is formally restored at high energy scales. The non-vanishing vacuum expectation values of the spurions induce a sequence of FS breaking and generate the observed hierarchy in the SM quark masses and mixings. The fact that there exists no explanation for it in the SM is known as the flavour puzzle. Gauging the non-abelian subgroup of the spontaneously broken FS, we interpret the associated Goldstone bosons as the longitudinal degrees of freedom of the corresponding massive gauge bosons. Integrating out the heavy Higgs modes in the Yukawa spurions leads directly to flavour-changing neutral currents (FCNCs) at tree level. The coefficients of the effective four-quark operators, resulting from the exchange of heavy flavoured gauge bosons, strictly follow the MFV principle. On the other hand, the Goldstone bosons associated with the global abelian symmetry group behave as weakly coupled axions which can be used to solve the strong CP problem within a modified Peccei-Quinn formalism. Models with a warped fifth dimension contain five-dimensional (5D) fermion bulk mass matrices in addition to their 5D Yukawa matrices, which thus represent an additional source of flavour violation beyond MFV. They can address the flavour puzzle since their eigenvalues allow for a different localisation of the fermion zero mode profiles along the extra dimension which leads to a hierarchy in the effective four-dimensional (4D) Yukawa matrices. At the same time, the fermion splitting introduces non-universal fermion couplings to Kaluza-Klein (KK) gauge boson modes, inducing tree-level FCNCs. Within a Randall-Sundrum model with custodial protection (RSc model) we carefully work

  14. Searches for Lepton Flavour Violation and Lepton Number Violation in Hadron Decays

    Seyfert, P

    2012-01-01

    In the Standard Model of particle physics, lepton flavour and lepton number are conserved quantities although no fundamental symmetry demands their conservation. I present recent results of searches for lepton flavour and lepton number violating hadron decays measured at the B factories and LHCb. In addition, the LHCb collaboration has recently performed a search for the lepton flavour violating decay $\\tau^- \\mu^- \\mu^- \\mu^+$ The obtained upper exclusion limit, that has been presented in this talk for the first time, is of the same order of magnitude as those observed at the B factories. This is the first search for a lepton flavour violating $\\tau$ decay at a hadron collider.

  15. Revisiting Lepton Flavour Universality in B Decays

    Feruglio, Ferruccio; Pattori, Andrea

    2016-01-01

    Lepton flavour universality (LFU) in B-decays is revisited in a model-independent way by considering semileptonic operators defined at a scale Lambda above the electroweak scale v. The importance of quantum effects, so far neglected in the literature, is emphasised. We construct the low-energy effective Lagrangian taking into account the running effects from Lambda down to v through the one-loop renormalization group equations (RGE) in the limit of exact electroweak symmetry and QED RGEs from v down to the 1 GeV scale. The most important quantum effects turn out to be the modification of the leptonic couplings of the vector boson Z and the generation of a purely leptonic effective Lagrangian. Large LFU breaking effects in Z and tau decays and visible lepton flavour violating (LFV) effects in the processes tau -> mu ll, tau -> mu rho, tau -> mu pi and tau -> mu eta^(') are induced.

  16. Leptonic Dirac CP violation predictions from residual discrete symmetries

    I. Girardi

    2016-01-01

    Full Text Available Assuming that the observed pattern of 3-neutrino mixing is related to the existence of a (lepton flavour symmetry, corresponding to a non-Abelian discrete symmetry group Gf, and that Gf is broken to specific residual symmetries Ge and Gν of the charged lepton and neutrino mass terms, we derive sum rules for the cosine of the Dirac phase δ of the neutrino mixing matrix U. The residual symmetries considered are: i Ge=Z2 and Gν=Zn, n>2 or Zn×Zm, n,m≥2; ii Ge=Zn, n>2 or Zn×Zm, n,m≥2 and Gν=Z2; iii Ge=Z2 and Gν=Z2; iv Ge is fully broken and Gν=Zn, n>2 or Zn×Zm, n,m≥2; and v Ge=Zn, n>2 or Zn×Zm, n,m≥2 and Gν is fully broken. For given Ge and Gν, the sum rules for cos⁡δ thus derived are exact, within the approach employed, and are valid, in particular, for any Gf containing Ge and Gν as subgroups. We identify the cases when the value of cos⁡δ cannot be determined, or cannot be uniquely determined, without making additional assumptions on unconstrained parameters. In a large class of cases considered the value of cos⁡δ can be unambiguously predicted once the flavour symmetry Gf is fixed. We present predictions for cos⁡δ in these cases for the flavour symmetry groups Gf=S4, A4, T′ and A5, requiring that the measured values of the 3-neutrino mixing parameters sin2⁡θ12, sin2⁡θ13 and sin2⁡θ23, taking into account their respective 3σ uncertainties, are successfully reproduced.

  17. Implication of Higgs mediated Flavour Changing Neutral Currents with Minimal Flavour Violation

    Rebelo, M N

    2015-01-01

    We analise phenomenological implications of two Higgs doublet models with Higgs flavour changing neutral currents suppressed in the quark sector by small entries of the Cabibbo-Kokayashi-Maskawa matrix. This suppression occurs in a natural way since it is the result of a symmetry applied to the Lagrangian. These type of models were proposed some time ago by Branco Grimus and Lavoura. Our results clearly show that these class of models allow for new physical scalars, with masses which are reachable at the LHC. The imposed symmetry severely reduces the number of free parameters and allows for predictions. Therefore these models can eventually be proved right or eliminated experimentally.

  18. Flavour Compounds in Fungi

    Ravasio, Davide Antonio

    Fungi produce a variety of volatile organic compounds (VOCs) during their primary or secondary metabolism and with a wide range of functions. The main focus of this research work has been put on flavour molecules that are produced during fermentation processes, mainly esters and alcohols derived...

  19. KLOE results in flavour physics and prospects for KLOE-2

    A review of the most recent results in flavour physics obtained by the KLOE experiment at DAΦNE collider together with prospects for kaon physics at KLOE-2 is presented. A brief description of KS meson lifetime measurement and determination of upper limit for BR(Ks→3π0) are discussed. In addition a CPT symmetry test in the Standard Model Extension framework and study of the Dalitz plot of η→π+π−π0 are reported. Last two sections are devoted to the KLOE-2 project and prospects in flavour physics

  20. KLOE results in flavour physics and prospects for KLOE-2

    Czerwiński, E., E-mail: eryk.czerwinski@uj.edu.pl [Institute of Physics, Jagiellonian University, Cracow (Poland); Babusci, D.; Badoni, D.; Balwierz, I.; Bencivenni, G.; Bini, C.; Bloise, C.; Bocci, V.; Bossi, F.; Branchini, P.; Budano, A.; Caldeira Balkeståhl, L.; Capon, G.; Ceradini, F.; Ciambrone, P.; Czerwiński, E.; Dané, E.; De Lucia, E.; De Robertis, G.; De Santis, A.; and others

    2013-08-15

    A review of the most recent results in flavour physics obtained by the KLOE experiment at DAΦNE collider together with prospects for kaon physics at KLOE-2 is presented. A brief description of K{sub S} meson lifetime measurement and determination of upper limit for BR(K{sub s}→3π{sup 0}) are discussed. In addition a CPT symmetry test in the Standard Model Extension framework and study of the Dalitz plot of η→π{sup +}π{sup −}π{sup 0} are reported. Last two sections are devoted to the KLOE-2 project and prospects in flavour physics.

  1. Gauge Invariants and Correlators in Flavoured Quiver Gauge Theories

    Mattioli, Paolo

    2016-01-01

    In this paper we study the construction of holomorphic gauge invariant operators for general quiver gauge theories with flavour symmetries. Using a characterisation of the gauge invariants in terms of equivalence classes generated by permutation actions, along with representation theory results in symmetric groups and unitary groups, we give a diagonal basis for the 2-point functions of holomorphic and anti-holomorphic operators. This involves a generalisation of the previously constructed Quiver Restricted Schur operators to the flavoured case. The 3-point functions are derived and shown to be given in terms of networks of symmetric group branching coefficients. The networks are constructed through cutting and gluing operations on the quivers.

  2. Charged-lepton flavour physics

    Andreas Hoecker

    2012-11-01

    This write-up on a talk at the 2011 Lepton–Photon symposium in Mumbai, India, summarizes recent results in the charged-lepton flavour sector. Searches for charged-lepton flavour violation, lepton electric dipole moments and flavour-conserving CP violation are reviewed here. Recent progress in -lepton physics and in the Standard Model prediction of the muon anomalous magnetic moment is also discussed.

  3. Flavour Tagging with the LHCb experiment

    Birnkraut, Alex

    2015-01-01

    Measurements of flavour oscillations and time-dependent CP asymmetries in neutral B meson systems require knowledge of the b quark production flavour. This identification is performed by the Flavour Tagging.

  4. Flavour-changing Higgs couplings in a class of two Higgs doublet models

    Botella, F.J. [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Branco, G.C. [Universitat de Valencia-CSIC, Departament de Fisica Teorica y IFIC, Burjassot (Spain); Instituto Superior Tecnico (IST), Lisboa Univ., Departamento de Fisica and Centro de Fisica Teorica de Particulas (CFTP), Lisbon (Portugal); Nebot, M. [Instituto Superior Tecnico (IST), Lisboa Univ., Centro de Fisica Teorica de Particulas (CFTP), Lisbon (Portugal); Rebelo, M.N. [Instituto Superior Tecnico (IST), Lisboa Univ., Departamento de Fisica and Centro de Fisica Teorica de Particulas (CFTP), Lisbon (Portugal)

    2016-03-15

    We analyse various flavour-changing processes like t → hu, hc, h → τe, τμ as well as hadronic decays h @→ bs, bd, in the framework of a class of two Higgs doublet models where there are flavour-changing neutral scalar currents at tree level. These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as tan β. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and there fore it is natural and stable under the renormalisation group. We show that in some of the models the rates of the above flavour-changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular μ @→ eγ. (orig.)

  5. Flavour Changing Higgs Couplings in a Class of Two Higgs Doublet Models

    Botella, F J; Nebot, M; Rebelo, M N

    2015-01-01

    We analyse various flavour changing processes like $t\\to hu,hc$, $h\\to \\tau e,\\tau\\mu$ as well as hadronic decays $h\\to bs,bd$, in the framework of a class of two Higgs doublet models where there are flavour changing neutral scalar currents at tree level. These models have the remarkable feature of having these flavour-violating couplings entirely determined by the CKM and PMNS matrices as well as $\\tan\\beta$. The flavour structure of these scalar currents results from a symmetry of the Lagrangian and therefore it is natural and stable under the renormalization group. We show that in some of the models the rates of the above flavour changing processes can reach the discovery level at the LHC at 13 TeV even taking into account the stringent bounds on low energy processes, in particular $\\mu\\to e\\gamma$.

  6. Symmetries, Symmetry Breaking, Gauge Symmetries

    Strocchi, Franco

    2015-01-01

    The concepts of symmetry, symmetry breaking and gauge symmetries are discussed, their operational meaning being displayed by the observables {\\em and} the (physical) states. For infinitely extended systems the states fall into physically disjoint {\\em phases} characterized by their behavior at infinity or boundary conditions, encoded in the ground state, which provide the cause of symmetry breaking without contradicting Curie Principle. Global gauge symmetries, not seen by the observables, are nevertheless displayed by detectable properties of the states (superselected quantum numbers and parastatistics). Local gauge symmetries are not seen also by the physical states; they appear only in non-positive representations of field algebras. Their role at the Lagrangian level is merely to ensure the validity on the physical states of local Gauss laws, obeyed by the currents which generate the corresponding global gauge symmetries; they are responsible for most distinctive physical properties of gauge quantum field ...

  7. Flavour Physics and CP Violation

    Pich, Antonio

    2013-01-01

    An introductory overview of the Standard Model description of flavour is presented. The main emphasis is put on present tests of the quark-mixing matrix structure and the phenomenological determination of its parameters. Special attention is given to the experimental evidences of CP violation and their important role in our understanding of flavour dynamics.

  8. Anarchic Yukawas and top partial compositeness: the flavour of a successful marriage

    Cacciapaglia, Giacomo; Flacke, Thomas; Lee, Seung J; Parolini, Alberto; Serôdio, Hugo

    2015-01-01

    The top quark can be naturally singled out from other fermions in the Standard Model due to its large mass, of the order of the electroweak scale. We follow this reasoning in models of pseudo Nambu Goldstone Boson composite Higgs, which may derive from an underlying confining dynamics. We consider a new class of flavour models, where the top quark obtains its mass via partial compositeness, while the lighter fermions acquire their masses by a deformation of the dynamics generated at a high flavour scale. One interesting feature of such scenario is that it can avoid all the flavour constraints without the need of flavour symmetries, since the flavour scale can be pushed high enough. We show that both flavour conserving and violating constraints can be satisfied with top partial compositeness without invoking any flavour symmetry for the up-type sector, in the case of the minimal SO(5)/SO(4) coset with top partners in the four-plet and singlet of SO(4). In the down-type sector, some degree of alignment is requi...

  9. Anarchic Yukawas and top partial compositeness: the flavour of a successful marriage

    Cacciapaglia, Giacomo; Cai, Haiying; Flacke, Thomas; Lee, Seung J.; Parolini, Alberto; Serôdio, Hugo

    2015-06-01

    The top quark can be naturally singled out from other fermions in the Standard Model due to its large mass, of the order of the electroweak scale. We follow this reasoning in models of pseudo Nambu Goldstone Boson composite Higgs, which may derive from an underlying confining dynamics. We consider a new class of flavour models, where the top quark obtains its mass via partial compositeness, while the lighter fermions acquire their masses by a deformation of the dynamics generated at a high flavour scale. One interesting feature of such scenario is that it can avoid all the flavour constraints without the need of flavour symmetries, since the flavour scale can be pushed high enough. We show that both flavour conserving and violating constraints can be satisfied with top partial compositeness without invoking any flavour symmetry for the up-type sector, in the case of the minimal SO(5)/SO(4) coset with top partners in the four-plet and singlet of SO(4). In the down-type sector, some degree of alignment is required if all down-type quarks are elementary. We show that taking the bottom quark partially composite provides a dynamical explanation for the hierarchy causing this alignment. We present explicit realisations of this mechanism which do not require to include additional bottom partner fields. Finally, these conclusions are generalised to scenarios with non-minimal cosets and top partners in larger representations.

  10. Food contact materials, flavouring substances and smoke flavourings

    Engel K-H

    2012-10-01

    Full Text Available

    The EFSA Panel on Food Additives, Flavourings, Processing Aids and Materials in Contact with Food (AFC Panel and the subsequent Panel on Food Contact Materials, Enzymes, Flavourings and Processing Aids (CEF Panel have undertaken evaluations of the safety of flavourings (both chemically defined substances and mixtures such as smoke flavourings and food contact materials (FCM, as well as assessments on other substances used in food. The major progress in methodologies for the evaluation of the safety of these substances is highlighted in this article. By December 2011, scientific opinions had been adopted for 247 substances for food contact materials, mainly plastics. Adoption of a series of opinions on active and/or intelligent packaging substances and on recycling processes of plastics is planned between July 2012 and December 2013. Panel opinions, EFSA statements/reports and guidance documents were published on specific issues and on substances for which there was an urgent request for safety evaluation (for example isopropylthioxanthone (ITX, bisphenol A (BPA, phthalates, epoxidised soybean oil (ESBO, benzophenone and 4-methylbenzophenone. By 2009, the AFC and CEF Panels had completed the safety review of 2 067 flavourings substances used in the EU. Additional data, which were requested for 404 substances, are currently under evaluation or have been generated. Eleven smoke flavourings have been evaluated, and the CEF Panel has prepared a guidance document on the future data required for the evaluation of flavourings.

  11. Dark matter and observable Lepton Flavour Violation

    Heurtier, Lucien

    2016-01-01

    Seesaw models with leptonic symmetries allow right-handed (RH) neutrino masses at the electroweak scale, or even lower, at the same time having large Yukawa couplings with the Standard Model leptons, thus yielding observable effects at current or near-future lepton-flavour-violation (LFV) experiments. These models have been previously considered also in connection to low-scale leptogenesis, but the combination of observable LFV and successful leptogenesis has appeared to be difficult to achieve unless the leptonic symmetry is embedded into a larger one. In this paper, instead, we follow a different route and consider a possible connection between large LFV rates and Dark Matter (DM). We present a model in which the same leptonic symmetry responsible for the large Yukawa couplings guarantees the stability of the DM candidate, identified as the lightest of the RH neutrinos. The spontaneous breaking of this symmetry, caused by a Majoron-like field, also provides a mechanism to produce the observed relic density ...

  12. Quark Yukawa pattern from spontaneous breaking of flavour $SU(3)^3$

    Nardi, Enrico

    2015-01-01

    A $SU(3)_Q \\times SU(3)_u \\times SU(3)_d$ invariant scalar potential breaking spontaneously the quark flavour symmetry can explain the standard model flavour puzzle. The approximate alignment in flavour space of the vacuum expectation values of the up and down `Yukawa fields' results as a dynamical effect. The observed quark mixing angles, the weak CP violating phase, and hierarchical quark masses can be all reproduced at the cost of introducing additional (auxiliary) scalar multiplets, but without the need of introducing hierarchical parameters.

  13. Lepton Flavour Violation in a Left-Right Symmetric Model

    Pastor, S; Valle, José W F; Pastor, Sergio; Rindani, Saurabh D.; Valle, Jose W.F.

    1999-01-01

    We consider in this paper a Left-Right symmetric gauge model in which a global lepton-number-like symmetry is introduced and broken spontaneously at a scale that could be as low as 10^4 GeV or so. The corresponding physical Nambu-Goldstone boson, which we call majoron and denote J, can have tree-level flavour-violating couplings to the charged fermions, leading to sizeable majoron-emitting lepton-flavour-violating weak decays. We consider explicitly a leptonic variant of the model and show that the branching ratios for \\mu -> e+J, \\tau -> e+J and \\tau -> \\mu+J decays can be large enough to fall within the sensitivities of future \\mu and \\tau factories. On the other hand the left-right gauge symmetry breaking scale may be as low as few TeV.

  14. Neutrino mass and mixing with discrete symmetry

    King, Stephen F.; Luhn, Christoph

    2013-05-01

    This is a review paper about neutrino mass and mixing and flavour model building strategies based on discrete family symmetry. After a pedagogical introduction and overview of the whole of neutrino physics, we focus on the PMNS mixing matrix and the latest global fits following the Daya Bay and RENO experiments which measure the reactor angle. We then describe the simple bimaximal, tri-bimaximal and golden ratio patterns of lepton mixing and the deviations required for a non-zero reactor angle, with solar or atmospheric mixing sum rules resulting from charged lepton corrections or residual trimaximal mixing. The different types of see-saw mechanism are then reviewed as well as the sequential dominance mechanism. We then give a mini-review of finite group theory, which may be used as a discrete family symmetry broken by flavons either completely, or with different subgroups preserved in the neutrino and charged lepton sectors. These two approaches are then reviewed in detail in separate chapters including mechanisms for flavon vacuum alignment and different model building strategies that have been proposed to generate the reactor angle. We then briefly review grand unified theories (GUTs) and how they may be combined with discrete family symmetry to describe all quark and lepton masses and mixing. Finally, we discuss three model examples which combine an SU(5) GUT with the discrete family symmetries A4, S4 and Δ(96).

  15. Flavour in supersymmetric Grand Unification a democratic approach

    Barbieri, Riccardo; Dvali, Gia; Hall, L; Strumia, A

    1994-01-01

    We consider the flavour problem in a supersymmetric Grand Unified theory with gauged SU(6) group, where the Higgs doublets are understood as pseudo-Goldstone bosons of a larger $\\SU(6)\\otimes\\SU(6)$ global symmetry of the Higgs superpotential. A key element of this work is that we never appeal to any flavour symmetry. One main interesting feature emerges: only one of the light fermions, an up-type quark, to be identified with the top, can get a Yukawa coupling at renormalizable level. This fact, together with bottom-tau Yukawa unification, also implied in our scheme, gives rise to a characteristic correlation between the top and the Higgs mass. By including a flavour-blind discrete symmetry and requiring that all higher dimensional operators be mediated by the exchange of appropriate heavy multiplets, it is possible to give an approximate description of all masses and mixing angles in term of a hierarchy of grand unified scales. A special ``texture'' arises, implying a relation between the top mass and the th...

  16. Flavour chemicals in electronic cigarette fluids

    Tierney, Peyton A; Karpinski, Clarissa D; Jessica E Brown; Luo, Wentai; Pankow, James F.

    2015-01-01

    Background Most e-cigarette liquids contain flavour chemicals. Flavour chemicals certified as safe for ingestion by the Flavor Extracts Manufacturers Association may not be safe for use in e-cigarettes. This study identified and measured flavour chemicals in 30 e-cigarette fluids. Methods Two brands of single-use e-cigarettes were selected and their fluids in multiple flavour types analysed by gas chromatography/mass spectrometry. For the same flavour types, and for selected confectionary fla...

  17. Critical Number of Flavours in QED

    Bashir, A; Gutiérrez-Guerrero, L X; Tejeda-Yeomans, M E

    2011-01-01

    We demonstrate that in unquenched quantum electrodynamics (QED), chiral symmetry breaking ceases to exist above a critical number of fermion flavours $N_f$. This is a necessary and sufficient consequence of the fact that there exists a critical value of electromagnetic coupling $\\alpha$ beyond which dynamical mass generation gets triggered. We employ a multiplicatively renormalizable photon propagator involving leading logarithms to all orders in $\\alpha$ to illustrate this. We study the flavour and coupling dependence of the dynamically generated mass analytically as well as numerically. We also derive the scaling laws for the dynamical mass as a function of $\\alpha$ and $N_f$. Up to a multiplicative constant, these scaling laws are related through $(\\alpha, \\alpha_c) \\leftrightarrow (1/N_f, 1/N_f^c)$. Calculation of the mass anomalous dimension $\\gamma_m$ shows that it is always greater than its value in the quenched case. We also evaluate the $\\beta$-function. The criticality plane is drawn in the $(\\alpha...

  18. B decays and lepton flavour (universality) violation

    Crivellin, A.

    2016-07-01

    LHCb found hints for physics beyond the standard model in Bto K^*μ^+μ^- , Bto K^*μ^+μ^-/Bto K^*e^+e^- and B_stoφμ^+μ^- . In addition, the BABAR results for Bto D^{(*)}τν and the CMS excess in htoτ^±μ^∓ also point towards lepton flavour (universality) violating new physics. While Bto D^{(*)}τν and htoτ^±μ^∓ can be naturally explained by an extended Higgs sector, the probably most promising explanation for the bto sμμ anomalies is a Z' boson. Furthermore, combining a 2HDM with a gauged L_μ-L_τ symmetry allows for explaining the bto sμ^+μ^- anomalies and htoτ^±μ^∓ simultaneously, with interesting correlations to τto3μ . In the light of these deviations from the SM we also discuss the possibilities of observing lepton flavour violating B decays ( e.g. Bto K^{(*)}τ^±μ^∓ and B_stoτ^±μ^∓ in Z^' models.

  19. Heavy Flavour Production at HERA

    ZEUS and H1 results on heavy quark production using the HERA data from 1995 to 2000 are summarised with emphasis on unresolved problems. The HERA upgrade and its impact on future heavy flavour measurements is briefly discussed

  20. CP violation versus flavour in supersymmetric theories

    Abel, S.; Branco, G. C.; Khalil, S.

    2003-09-01

    We show that the quark flavour structure and CP violating phenomena are strongly correlated in supersymmetric theories. For a generic pattern of supersymmetry breaking the two broad categories of Yukawa couplings, democratic and hierarchical textures, have entirely different phenomenological implications. With hierarchical Yukawas, the rephasing invariant phase, arg(VusVcbVcb∗Vcs∗), in the CKM mixing matrix has to be of order unity, while the SUSY CP violating phases are severely constrained by electric dipole moments, giving rise to the so-called SUSY CP problem. With democratic Yukawas, all experimental CP results can be accommodated with small values for the CKM and SUSY CP violating phases (i.e., CP can be considered as an approximate symmetry at the high energy scale). We also show that within this scenario, an entirely real CKM matrix in supersymmetric models is still allowed by the present experimental results.

  1. CP violation versus flavour in supersymmetric theories

    Abel, S A; Khalil, S

    2003-01-01

    We show that the quark flavour structure and CP violating phenomena are strongly correlated in supersymmetric theories. For a generic pattern of supersymmetry breaking the two broad categories of Yukawa couplings, democratic and hierarchical textures, have entirely different phenomenological implications. With hierarchical Yukawas, the rephasing invariant phase, arg(V_us V_cb V_cb^* V_cs^*), in the CKM mixing matrix has to be of order unity, while the SUSY CP violating phases are severely constrained by electric dipole moments, giving rise to the so-called SUSY CP problem. With democratic Yukawas, all experimental CP results can be accommodated with small values for the CKM and SUSY CP violating phases (i.e., CP can be considered as an approximate symmetry at the high energy scale). We also show that within this scenario, an entirely real CKM matrix in supersymmetric models is still allowed by the present experimental results.

  2. A 125 GeV composite Higgs boson versus flavour and electroweak precision tests

    Barbieri, Riccardo; Sala, Filippo; Straub, David M; Tesi, Andrea

    2012-01-01

    A composite Higgs boson of 125 GeV mass, only mildly fine-tuned, requires top partners with a semi-perturbative coupling and a mass not greater than about a TeV. We analyze the strong constraints on such picture arising from flavour and electroweak precision tests in models of partial compositeness. We consider different representations for the composite fermions and compare the case of an anarchic flavour structure to models with a U(3)^3 and U(2)^3 flavour symmetry. Although non trivially, some models emerge that look capable of accommodating a 125 GeV Higgs boson with top partners in an interesting mass range for discovery at the LHC as well as associated flavour signals.

  3. Radiatively induced flavour violation in the general two-Higgs doublet model with Yukawa alignment

    The most general two-Higgs doublet model contains new sources of flavour violation that are usually in conflict with the experimental constraints. One possibility to suppress the exotic contribution to the flavour changing neutral currents consists on imposing the alignment of the Yukawa couplings. This condition presumably holds at a high-energy scale and is spoiled by the radiative corrections. We compute in this Letter the size of the radiatively induced flavour violating Higgs couplings at the electroweak scale. These also yield the absolute lower bound on the size of the exotic contributions to the flavour changing neutral currents in any two-Higgs doublet model, barring cancellations and the existence of discrete symmetries. We show that these contributions are well below the experimental bounds in large regions of the parameter space.

  4. A Grand Delta(96) x SU(5) Flavour Model

    King, Stephen F; Stuart, Alexander J

    2012-01-01

    Recent results from the Daya Bay and RENO reactor experiments have measured the smallest lepton mixing angle and found it to have a value of theta_13 approximately 9 degrees. This result presents a new challenge for the existing paradigms of discrete flavour symmetries which attempt to describe all quark and lepton masses and mixing angles. Here we propose a Supersymmetric Grand Unified Theory of Flavour based on Delta(96) x SU(5), together with a U(1) x Z3 symmetry, including a full discussion of Delta(96) in a convenient basis. The Grand Delta(96) x SU(5) Flavour Model relates the quark mixing angles and masses in the form of the Gatto-Sartori-Tonin relation and realises the Georgi-Jarlskog mass relations between the charged leptons and down-type quarks. We predict a Bi-trimaximal (not Tri-bimaximal) form of neutrino mixing matrix, which, after including charged lepton corrections with zero phase, leads to the following GUT scale predictions for the atmospheric, solar, and reactor mixing angles: theta_23=36...

  5. Flavour Physics of Leptons and Dipole Moments.

    Raidal, M.; van der Schaaf, A.; Bigi, I.; Mangano, M.L.; Semertzidis, Y.; Abel, S.; Albino, S.; Antusch, S.; Arganda, E.; Bajc, B.; Banerjee, S.; Biggio, C.; Blanke, M.; W. Bonivento; Branco, G. C.

    2008-01-01

    This chapter of the report of the ``Flavour in the era of the LHC'' Workshop discusses the theoretical, phenomenological and experimental issues related to flavour phenomena in the charged lepton sector and in flavour-conserving CP-violating processes. We review the current experimental limits and the main theoretical models for the flavour structure of fundamental particles. We analyze the phenomenological consequences of the available data, setting constraints on explicit models beyond the ...

  6. Light third-generation squarks from flavour gauge messengers

    We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3)F symmetry acting on the quark superfields. If SU(3)F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3)F breaking

  7. Light third-generation squarks from flavour gauge messengers

    We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3)F symmetry acting on the quark superfields. If SU(3)F is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3)F breaking.

  8. Higgs and flavour as doors to new physics

    Sala, Filippo

    2016-04-01

    A natural solution to the hierarchy problem of the Fermi scale motivates signals of New Physics at current and near-future experiments. After a critical synthesis of this general motivation, we concentrate our attention on the interplay between LHC searches for new resonances, and precision measurements of both Higgs couplings and flavour violating observables. We do so for i) the Higgs sectors of the NMSSM and MSSM, as paradigmatic examples of theories providing extra scalars, and for ii) CKM-like flavour symmetries, with a focus on U(2)3. This article is mainly based on several papers by the author, but it also reviews other recent related results. Its goal is to provide a synthetic, yet comprehensive, orientation on these subjects, at the dawn of several (ATLAS and CMS, LHCb, NA62, etc.) forthcoming experimental results.

  9. Light third-generation squarks from flavour gauge messengers

    Bruemmer, Felix [International School for Advanced Studies, Trieste (Italy); Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); McGarrie, Moritz [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Univ. of the Witwatersrand, Johannesburg (South Africa). School of Physics and Centre for Theoretical Physics; Weiler, Andreas [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); CERN - European Organization for Nuclear Research, Geneva (Switzerland). Theory Div.

    2014-04-15

    We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3){sub F} symmetry acting on the quark superfields. If SU(3){sub F} is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3){sub F} breaking.

  10. Light third-generation squarks from flavour gauge messengers

    Brümmer, Felix [SISSA/ISAS,Via Bonomea 265, Trieste I-34136 (Italy); Deutsches Elektronen-Synchrotron DESY,Notkestrasse 85, D-22607 Hamburg (Germany); McGarrie, Moritz [Deutsches Elektronen-Synchrotron DESY,Notkestrasse 85, D-22607 Hamburg (Germany); National Institute for Theoretical Physics, School of Physics,and Centre for Theoretical Physics, University of the Witwatersrand,Johannesburg, WITS 2050 (South Africa); Weiler, Andreas [Deutsches Elektronen-Synchrotron DESY,Notkestrasse 85, D-22607 Hamburg (Germany); CERN Theory Division,CH-1211 Geneva 23 (Switzerland)

    2014-04-10

    We study models of gauge-mediated supersymmetry breaking with a gauged horizontal SU(3){sub F} symmetry acting on the quark superfields. If SU(3){sub F} is broken non-supersymmetrically by F-term vacuum expectation values, the massive gauge bosons and gauginos become messengers for SUSY breaking mediation. These gauge messenger fields induce a flavour-dependent, negative contribution to the soft masses of the squarks at one loop. In combination with the soft terms from standard gauge mediation, one obtains large and degenerate first- and second-generation squark masses, while the stops and sbottoms are light. We discuss the implications of this mechanism for the superparticle spectrum and for flavour precision observables. We also provide an explicit realization in a model with simultaneous SUSY and SU(3){sub F} breaking.

  11. Non-universal Z' models with protected flavour-changing interactions

    Jung, Martin

    2016-01-01

    We define a new class of Z' models with neutral flavour-changing interactions at tree level in the down-quark sector. They are related in an exact way to elements of the quark mixing matrix due to an underlying flavoured U(1)' gauge symmetry, rendering these models particularly predictive. The same symmetry implies lepton-flavour non-universal couplings, fully determined by the gauge structure of the model. Our models allow to address several presently observed deviations from the SM and specific correlations among the new physics contributions to the Wilson coefficients C9,10(l) can be tested in b->sll transitions. We furthermore predict lepton-universality violations in Z' decays, testable at the LHC.

  12. Natural suppression of flavour-changing neutral currents in supersymmetric gauge theories

    Induced flavour-changing neutral currents (FCNC) in supersymmetric unified theories are investigated both in models with the standard SU(2)sub(L) x U(1) gauge symmetry and in models with an extra U tilde(1) gauge symmetry. Supersymmetric extension of the natural flavour conservation laws for neutral currents is obtained by adding a condition regarding the assumed type of supersymmetry breaking. This condition ensures no direct flavour-changing couplings of neutral gauge-Higgs fermions and at the same time is necessary and sufficient for the natural suppression of the induced FCNC. It is found that in the class of models satisfying the new condition the contribution of the scalar partners of quarks to the induced strangeness-changing neutral current is comparable to that of the quarks in K sub(L) → μantiμ, while it is negligibly small in K sub(L)-K sub(S) mass difference. (author)

  13. Heavy flavour at the Large Hadron Collider

    Gibson, V

    2013-01-01

    Heavy flavour physics provides a crucial role in the validation of the Standard Model of particle physics and in the search for new phenomena beyond. This review provides a personal summary of the headline results as of May 2013 from the LHC heavy flavour community in the subject areas of heavy flavour production and spectroscopy, mixing and CP violation and rare decays.

  14. Flavour-active wine yeasts

    Cordente, Antonio G.; Curtin, Christopher D.; Varela, Cristian; Pretorius, Isak S.

    2012-01-01

    The flavour of fermented beverages such as beer, cider, saké and wine owe much to the primary fermentation yeast used in their production, Saccharomyces cerevisiae. Where once the role of yeast in fermented beverage flavour was thought to be limited to a small number of volatile esters and higher alcohols, the discovery that wine yeast release highly potent sulfur compounds from non-volatile precursors found in grapes has driven researchers to look more closely at how choice of yeast can infl...

  15. Dynamical generation of flavour

    Charanjit Kaur Khosa

    2016-02-01

    We propose the generation of Standard Model fermion hierarchy by the extension of renormalizable SO(10) GUT with O(Ng) family gauge symmetry. In this scenario, Higgs representations of SO(10) also carry family indices and are called Yukawons. Vacuum expectation values of these Yukawon fields break GUT and family symmetry and generate MSSM Yukawa couplings dynamically. We have demonstrated this idea using $10 \\oplus 210 \\oplus 126 \\oplus \\overline{126}$ Higgs irrep, ignoring the contribution of 120-plet which is, however, required for complete fitting of fermion mass-mixing data. The effective MSSM matter fermion couplings to the light Higgs pair are determined by the null eigenvectors of the MSSM-type Higgs doublet superfield mass matrix $\\mathcal{H}$. A consistency condition on the doublet ([1, 2,±1]) mass matrix (Det($\\mathcal{H}$) = 0) is required to keep one pair of Higgs doublets light in the effective MSSM. We show that the Yukawa structure generated by null eigenvectors of $\\mathcal{H}$ are of generic kind required by the MSSM. A hidden sector with a pair of (Sab; ab) fields breaks supersymmetry and facilitates DO(Ng) = 0. SUSY breaking is communicated via supergravity. In this scenario, matter fermion Yukawa couplings are reduced from 15 to just 3 parameters in MSGUT with three generations.

  16. Heavy flavours: working group summary

    Ali, Ahmed [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Gladilin, Leonid [Moscow State Univ. (Russian Federation). Scobeltsyn Inst. of Nuclear Physics; Tonelli, Diego [Fermi National Accelerator Lab., Batavia, IL (United States)

    2009-07-15

    The talks presented in the working group ''Heavy flavours'' of the DIS 2009 workshop are summarised. New and recently updated results from theory, proton antiproton and heavy ion colliders, as well from HERA and e{sup +}e{sup -} colliders are discussed. (orig.)

  17. Symmetries and Symmetry Breaking

    Van Oers, W T H

    2003-01-01

    In understanding the world of matter, the introduction of symmetry principles following experimentation or using the predictive power of symmetry principles to guide experimentation is most profound. The conservation of energy, linear momentum, angular momentum, charge, and CPT involve fundamental symmetries. All other conservation laws are valid within a restricted subspace of the four interactions: the strong, the electromagnetic, the weak, and the gravitational interaction. In this paper comments are made regarding parity violation in hadronic systems, charge symmetry breaking in two nucleon and few nucleon systems, and time-reversal-invariance in hadronic systems.

  18. Flavour physics and CP violation

    Rukmani Mohanta; Anjan Kumar Giri

    2010-05-01

    It is well known that the study of flavour physics and CP violation is very important to critically test the Standard Model and to look for possible signature of new physics beyond it. The observation of CP violation in kaon system in 1964 has ignited a lot of experimental and theoretical efforts to understand its origin and to look for CP violation effects in other systems besides the neutral kaons. The two -factories BABAR and BELLE, along with other experiments, in the last decade or so made studies in flavour physics and CP violation a very interesting one. In this article we discuss the status and prospectives of the flavour physics associated with the strange, charm and bottom sectors of the Standard Model. The important results in kaon sector will be briefly discussed. Recently, mixing in the charm system has been observed, which was being pursued for quite some time without any success. The smallness of the mixing parameters in the charm system is due to the hierarchical structure of the CKM matrix. Interestingly, so far we have not found CP violation in the charm system but in the future, with more dedicated experiments at charm threshold, the situation could change. Many interesting observations have been made in the case of bottom mesons and some of them show some kind of deviations from that of the Standard Model expectations which are mainly associated with the → flavour changing neutral current transitions. It is long believed that the system could be the harbinger of new physics since it is a system in which both bottom and strange quarks are the constituents. Recently, D0 and CDF announced their result for the mixing which is claimed to be the first possible new physics signature in the flavour sector. We plan to touch upon all important issues pointing out both theoretical and experimental developments and future prospects in this review article.

  19. Relating quarks and leptons with the T7 flavour group

    Cesar Bonilla

    2015-03-01

    Full Text Available In this letter we present a model for quarks and leptons based on T7 as flavour symmetry, predicting a canonical mass relation between charged leptons and down-type quarks proposed earlier. Neutrino masses are generated through a Type-I seesaw mechanism, with predicted correlations between the atmospheric mixing angle and neutrino masses. Compatibility with oscillation results leads to lower bounds for the lightest neutrino mass as well as for the neutrinoless double beta decay rates, even for normal neutrino mass hierarchy.

  20. Flavour alignment in physics beyond the standard model

    There are numerous reasons to think that the Standard Model of physics is not the ultimate theory of nature on very small scales. However, attempts to construct theories that go beyond the Standard Model generically lead to high rates of flavour changing neutral processes that are in conflict with experiment: Quarks are the fundamental constituents of protons and neutrons. Together with electrons they form the visible matter of the universe1. They come in three generations or ''flavours''. In interactions, quarks of different generations can mix, i.e. a quark of one flavour can transform into a quark of another flavour. In the Standard Model, at first order in perturbation theory, such processes occur only via the exchange of a charged particle. Flavour changing neutral processes can only arise in processes involving loops of charged particles. This is due to the fact that all couplings of two quarks to a neutral particle are diagonal in the basis of the mass eigenstates of the quarks. There is thus no mixing of quarks of different flavour at first order. Since the loop processes are suppressed by a loop factor, the Standard Model predicts very low rates for neutral processes that change the flavour of quarks. So far, this is in agreement with experiment. In extensions of the Standard Model, new couplings to the quarks are usually introduced. In general there is no reason why the new coupling matrices should be diagonal in the mass basis of the quarks. These models therefore predict high rates for processes that mix quarks of different flavour. Extensions of the Standard Model must therefore have a non-trivial flavour structure. A possibility to avoid flavour violation is to assume that the new couplings are aligned with the mass matrices of the quarks, i.e. diagonal in the same basis. This alignment could be due to a flavour symmetry. In this thesis, two extensions of the Standard Model with alignment are studied. The first is a simple extension of the Standard

  1. Flavour alignment in physics beyond the standard model

    Braeuninger, Carolin Barbara

    2012-11-21

    There are numerous reasons to think that the Standard Model of physics is not the ultimate theory of nature on very small scales. However, attempts to construct theories that go beyond the Standard Model generically lead to high rates of flavour changing neutral processes that are in conflict with experiment: Quarks are the fundamental constituents of protons and neutrons. Together with electrons they form the visible matter of the universe1. They come in three generations or ''flavours''. In interactions, quarks of different generations can mix, i.e. a quark of one flavour can transform into a quark of another flavour. In the Standard Model, at first order in perturbation theory, such processes occur only via the exchange of a charged particle. Flavour changing neutral processes can only arise in processes involving loops of charged particles. This is due to the fact that all couplings of two quarks to a neutral particle are diagonal in the basis of the mass eigenstates of the quarks. There is thus no mixing of quarks of different flavour at first order. Since the loop processes are suppressed by a loop factor, the Standard Model predicts very low rates for neutral processes that change the flavour of quarks. So far, this is in agreement with experiment. In extensions of the Standard Model, new couplings to the quarks are usually introduced. In general there is no reason why the new coupling matrices should be diagonal in the mass basis of the quarks. These models therefore predict high rates for processes that mix quarks of different flavour. Extensions of the Standard Model must therefore have a non-trivial flavour structure. A possibility to avoid flavour violation is to assume that the new couplings are aligned with the mass matrices of the quarks, i.e. diagonal in the same basis. This alignment could be due to a flavour symmetry. In this thesis, two extensions of the Standard Model with alignment are studied. The first is a simple

  2. Chiral order and fluctuations in multi-flavour QCD

    Descotes-Genon, S; Stern, J

    2003-01-01

    Multi-flavour (N_f>=3) Chiral Perturbation Theory (ChPT) may exhibit instabilities due to vacuum fluctuations of sea q-bar q pairs. Keeping the fluctuations small would require a very precise fine-tuning of the low-energy constants L_4 and L_6 to L_4[crit](M_rho) = - 0.51 * 10^(-3), and L_6[crit](M_rho) = - 0.26 * 10^(-3). A small deviation from these critical values -- like the one suggested by the phenomenology of OZI-rule violation in the scalar channel -- is amplified by huge numerical factors inducing large effects of vacuum fluctuations. This would lead in particular to a strong N_f-dependence of chiral symmetry breaking and a suppression of multi-flavour chiral order parameters. A simple resummation is shown to cure the instability of N_f>=3 ChPT, but it modifies the standard expressions of some O(p^2) and O(p^4) low-energy parameters in terms of observables. On the other hand, for r=m_s/m > 15, the two-flavour condensate is not suppressed, due to the contribution induced by massive vacuum s-bar s pair...

  3. B-anomalies related to leptons and lepton flavour universality violation

    Crivellin, Andreas

    2016-01-01

    Several experiments observed deviations from the Standard Model (SM) in the flavour sector: LHCb found a $4-5\\,\\sigma$ discrepancy compared to the SM in $b\\to s\\mu^+\\mu^-$ transitions (recently supported by an Belle analysis) and CMS reported a non-zero measurement of $h\\to\\mu\\tau$ with a significance of $2.4\\,\\sigma$. Furthermore, BELLE, BABAR and LHCb founds hints for the violation of flavour universality in $B\\to D^{(*)}\\tau\

  4. The STAR Heavy Flavour Tracker

    In order to understand the partonic EOS of matter created at RHIC, one needs to study both the collectivity of the produced matter and the degree of thermalization. We propose to address this physics through the study of heavy flavour hadrons in high-energy nuclear collisions at RHIC. The heavy flavour tracker (HFT), a tracking upgrade of the STAR experiment, is being designed to provide an unambiguous measurement of charm hadrons through the direct reconstruction of hadronic decays. These measurements require high accuracy space points near the collision vertex. The current design of our detector uses a novel CMOS-based sensor, allowing for a low-mass and high-resolution detector element. We provide rate estimations for D0 v2 measurements in Au+Au collisions at 200 GeV

  5. The flavour of natural SUSY

    Bruemmer, Felix [SISSA/ISAS, Trieste (Italy); Kraml, Sabine; Kulkarni, Suchita; Smith, Christopher [Universite Grenoble-Alpes, CNRS/IN2P3, Laboratoire de Physique Subatomique et de Cosmologie, Grenoble Cedex (France)

    2014-09-15

    An inverted mass hierarchy in the squark sector, as in so-called ''natural supersymmetry'', requires non-universal boundary conditions at the mediation scale of supersymmetry breaking. We propose a formalism to define such boundary conditions in a basis-independent manner and apply it to generic scenarios where the third-generation squarks are light, while the first two-generation squarks are heavy and near-degenerate. We show that not only is our formalism particularly well suited to study such hierarchical squark mass patterns, but in addition the resulting soft terms at the TeV scale are manifestly compatible with the principle of minimal flavour violation, and thus automatically obey constraints from flavour physics. (orig.)

  6. Linking Natural Supersymmetry to Flavour Physics

    Dudas, Emilian; Pokorski, Stefan; Ziegler, Robert

    2013-01-01

    With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G \\times U(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit to the fermion masses and mixing is obtained with the same U(1) charges for the left- and right- handed quarks of the first two families and the right-handed bottom quark, and with zero charge for the left-handed top-bottom doublet and the the right handed top. The model shows an interesting indirect correlation between the correct prediction for the V_{ub}/V_{cb} ratio and large right-handed rotations in the (s,b) sector, required to diagonalise the Yukawa matrix. For the squarks, one obtains almost degenerate first two generations. The main source of the FCNC and CP violation effects is the splitting between the first two families and the right-handed sbottom determined by the relative size of F-term and D-term supersymmetry breaking. The presence of the larg...

  7. Flavour Physics with High-Luminosity Experiments

    2016-01-01

    With the first dedicated B-factory experiments BaBar (USA) and BELLE (Japan) Flavour Physics has entered the phase of precision physics. LHCb (CERN) and the high luminosity extension of KEK-B together with the state of the art BELLE II detector will further push this precision frontier. Progress in this field always relied on close cooperation between experiment and theory, as extraction of fundamental parameters often is very indirect. To extract the full physics information from existing and future data, this cooperation must be further intensified. This MIAPP programme aims in particular to prepare for this task by joining experimentalists and theorists in the various relevant fields, with the goal to build the necessary tools in face of the challenge of new large data sets. The programme will begin with a focus on physics with non-leptonic final states, continued by semileptonic B meson decays and Tau decays, and on various aspects of CP symmetry violation closer to the end. In addition, in the final ...

  8. Linking natural supersymmetry to flavour physics

    With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G×U(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry breaking. A good fit to the fermion masses and mixing is obtained with the same U(1) charges for the left- and right- handed quarks of the first two families and the right-handed bottom quark, and with zero charge for the left-handed top-bottom doublet and the the right handed top. The model shows an interesting indirect correlation between the correct prediction for the Vub/Vcb ratio and large right-handed rotations in the (s,b) sector, required to diagonalise the Yukawa matrix. For the squarks, one obtains almost degenerate first two generations. The main source of the FCNC and CP violation effects is the splitting between the first two families and the right-handed sbottom determined by the relative size of F-term and D-term supersymmetry breaking. The presence of the large right-handed rotation implies that the bounds on the masses of the first two families of squarks and the right handed sbottom are in a few to a few tens TeV range. The picture that emerges is light stops and left handed sbottom and much heavier other squarks

  9. Flavour Chemistry of Chicken Meat: A Review

    Jayasena, Dinesh D.; Ahn, Dong Uk; Nam, Ki Chang; Jo, Cheorun

    2013-01-01

    Flavour comprises mainly of taste and aroma and is involved in consumers’ meat-buying behavior and preferences. Chicken meat flavour is supposed to be affected by a number of ante- and post-mortem factors, including breed, diet, post-mortem ageing, method of cooking, etc. Additionally, chicken meat is more susceptible to quality deterioration mainly due to lipid oxidation with resulting off-flavours. Therefore, the intent of this paper is to highlight the mechanisms and chemical compounds res...

  10. Flavour perception: aroma, taste and texture interactions

    Tournier, Carole; Sulmont-Rossé, Claire; Guichard, Elisabeth

    2007-01-01

    Flavour perception is determinant for the acceptability of food products by consumers. Aroma and taste play an important role in flavour perception and it is well known that the chemical composition of the matrix and consequently its structure influences release and perception of flavour. However, from simultaneous measurements of human perception and physical concentration in vivo, texture – aroma and texture – taste interactions are not always explained by physico-chemical mechanisms. Moreo...

  11. Approaching Minimal Flavour Violation from an S4 x SU(5) SUSY GUT

    Dimou, Maria; Luhn, Christoph

    2015-01-01

    We show how approximate Minimal Flavour Violation (MFV) can emerge from an SU(5) Supersymmetric Grand Unified Theory (SUSY GUT) supplemented by an S4 x U(1) family symmetry, which provides a good description of all quark and lepton (including neutrino) masses, mixings and CP violation. Assuming a SUSY breaking mechanism which respects the family symmetry, we calculate in full explicit detail the low energy mass insertion parameters in the super-CKM basis, including the effects of canonical normalisation and renormalisation group running. We find that the very simple family symmetry S4 x U(1) is sufficient to approximately reproduce the effects of low energy MFV.

  12. Definitions of minimal flavour violation for leptons

    Neutrino masses imply the violation of lepton flavour and new physics beyond the Standard Model. However, flavour change has only been observed in oscillations. In analogy with the quark sector, we could deduce the existence of a principle of Minimal Flavour Violation also for Leptons (MFVL). Such an extension is not straightforward, since the mechanisms generating neutrino masses are unknown and many scenarios can be envisaged. Thus, we explore some possible definitions of MFVL and propose a notion that can include many models. We show, furthermore, that flavour violating processes are not necessarily controlled by the PMNS mixing matrix. (author)

  13. Flavour and Higgs physics near the Fermi scale

    Sala, Filippo

    2013-01-01

    After a discussion of the hierarchy problem of the Fermi scale, we study the flavour and Higgs boson(s) phenomenology of new physics close to it, both in general and in the specific cases of Supersymmetry and composite Higgs models. First, we promote the approximate U(2)^3 symmetry exhibited by the quark sector of the Standard Model to be a more fundamental symmetry of Nature, and explore its phenomenological consequences from an effective field theory point of view. We also study the embedding of natural Supersymmetry within the U(2)^3 framework, focusing in particular on the pattern of flavour and CP violation in B decays. Then we consider the CP-even scalar sector of the next-to-minimal supersymmetric Standard Model. We quantify the impact of current and foreseen measurements of the Higgs boson signal strengths on the physical parameters, deriving analytical relations for this purpose, and we outline a possible overall strategy to search for the other Higgs scalars. Finally we analyze the constraints from ...

  14. pi-pi and pi-K scatterings in three-flavour resummed chiral perturbation theory

    Descotes-Genon, S

    2008-01-01

    The (light but not-so-light) strange quark may play a special role in the low-energy dynamics of QCD. The presence of strange quark pairs in the sea may have a significant impact of the pattern of chiral symmetry breaking : in particular large differences can occur between the chiral limits of two and three massless flavours (i.e., whether m_s is kept at its physical value or sent to zero). This may induce problems of convergence in three-flavour chiral expansions. To cope with such difficulties, we introduce a new framework, called Resummed Chiral Perturbation Theory. We exploit it to analyse pi-pi and pi-K scatterings and match them with dispersive results in a frequentist framework. Constraints on three-flavour chiral order parameters are derived.

  15. Quark flavour observables in the Littlest Higgs model with T-parity after LHC Run 1

    Blanke, Monika; Recksiegel, Stefan

    2016-01-01

    The Littlest Higgs Model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. We present a new analysis of quark observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare $K$ and $B$ decays are still allowed to depart from their SM values. This includes $K^+\\to\\pi^+\

  16. Phenomenological Implications of an S4 x SU(5) SUSY GUT of Flavour

    Dimou, Maria; Luhn, Christoph

    2015-01-01

    We discuss the low energy phenomenological implications of an SU(5) Supersymmetric Grand Unified Theory (SUSY GUT) whose flavour structure is controlled by the family symmetry S4 x U(1), which provides a good description of all quark and lepton masses, mixings as well as CP violation. Although the model closely mimics Minimal Flavour Violation (MFV) as shown in arXiv:1511.07886, here we focus on the differences. We first present numerical estimates of the low energy mass insertion parameters, including canonical normalisation and renormalisation group running, for well-defined ranges of SUSY parameters and compare the naive model expectations to the numerical scans and the experimental bounds. Our results are then used to estimate the predictions for Electric Dipole Moments (EDMs), Lepton Flavour Violation (LFV), B and K meson mixing as well as rare B decays. The largest observable deviations from MFV come from the LFV process mu --> e gamma and the EDMs.

  17. Heavy flavour production at CMS

    Negro, Giulia

    2016-01-01

    Three recent results in heavy flavour production at the CMS experiment are addressed in this report. Measurements of the differential production cross sections of B hadron and quarkonium states in pp collisions at $\\sqrt{s} = 13$ TeV are presented. These are important tools to investigate heavy-quark production mechanisms in QCD. The dependences on transverse momentum and rapidity are investigated and comparisons with theory expectations and among different collision energies are provided. Also the new observation of $\\Upsilon(1S)\\Upsilon(1S)$ production is reported.

  18. Charged Lepton Flavour Violation in Supersymmetric Low-Scale Seesaw Models

    Ilakovac, Amon; Popov, Luka

    2013-01-01

    We study charged lepton flavour violation in low-scale seesaw models of minimal supergravity, which realize large neutrino Yukawa couplings thanks to approximate lepton-number symmetries. There are two dominant sources of lepton flavour violation in such models. The first source originates from the usual soft supersymmetry-breaking sector, whilst the second one is entirely supersymmetric and comes from the supersymmetric neutrino Yukawa sector. Within the framework of minimal supergravity, we consider both sources of lepton flavour violation, soft and supersymmetric, and calculate a number of possible lepton-flavour-violating transitions, such as the photonic decays of muons and taus, mu -> e gamma, tau -> e gamma and tau -> mu gamma, their neutrinoless three-body decays, mu -> e e e, tau -> e e e, tau -> mu mu mu, tau -> e e mu and tau -> e mu mu, and the coherent mu -> e conversion in nuclei. After taking into account the exclusion bounds placed by present experiments of lepton flavour violation, we derive ...

  19. Lepton flavour violation searches at the LHC

    Dawe, Edmund; The ATLAS collaboration

    2015-01-01

    Recent results from searches for lepton flavour violation performed by ATLAS and CMS in the $\\sqrt{s}=8~\\text{TeV}$ data are presented. The search for $Z\\rightarrow e\\mu$ and lepton flavour violating heavy neutral particle decays are summarized before covering the search for $H\\rightarrow \\mu \\tau$ in greater detail.

  20. Production of Japanese Soy-Sauce Flavours

    Sluis, van der C.

    2001-01-01

    The salt-tolerant yeasts Zygosaccharomyces rouxii and Candida versatilis are important for the formation of flavour in Japanese soy-sauce processes. In these processes Z. rouxii produces the flavour components ethanol, higher alcohols and 4-hydroxyfuranones, while C. versatilis is responsible for th

  1. Recent studies on the biogeneration of flavours

    Fuganti, Claudio; Zucchi, Gioia [CNR, Milan (Italy). Dipt. di Chimica del Politecnico

    1997-07-01

    The requirements by the flavour industry for large quantities of natural flavouring compounds, has stimulated the research for enzymatic procedures enabling the access from extractive precursor to rare odorants not accessible by extraction, including alcohols, aldehyde, lactones and sulfurated compounds. The ability of the SNIF-NMR technique in the authentication of the products is discussed.

  2. Flavour physics and CP-violation

    An introductory overview of the Standard Model description of flavour is presented. The main emphasis is put on present tests of the quark-mixing matrix structure and the phenomenological determination of its parameters. Special attention is given to the experimental evidence for CP-violation and its important role in our understanding of flavour dynamics. (author)

  3. Precision physics with heavy-flavoured hadrons

    Koppenburg, Patrick

    2015-01-01

    The understanding of flavour dynamics is one of the key aims of elementary particle physics. The last 15 years have witnessed the triumph of the Kobayashi-Maskawa mechanism, which describes all flavour changing transitions of quarks in the Standard Model. This important milestone has been reached owing to a series of experiments, in particular to those operating at the so-called $B$ factories, at the Tevatron, and now at the LHC. We briefly review status and perspectives of flavour physics, highlighting the results where the LHC has given the most significant contributions, notably including the recent observation of the $B_s^0\\to\\mu^+\\mu^-$ decay.

  4. Flavour Physics and Implication for New Phenomena

    Isidori, Gino

    2015-01-01

    Flavour physics represents one of the most interesting and, at the same time, less understood sector of the Standard Theory. On the one hand, the peculiar pattern of quark and lepton masses, and their mixing angles, may be the clue to some new dynamics occurring at high-energy scales. On the other hand, the strong suppression of flavour-changing neutral-current processes, predicted by the Standard Theory and confirmed by experiments, represents a serious challenge to extend the Theory. This article reviews both these aspects of flavour physics from a theoretical perspective.

  5. Selected topics in heavy flavour physics

    We review the status of flavour physics in spring 2014. The numerous accurate new measurements of flavour experiments have enabled us to test our theoretical understanding of flavour processes with an unprecedented precision. At first sight the dominant amount of measurements seems to be standard model like. Having a closer look one finds, however, that in most of the observables there is still some considerable space for new effects. In addition many discrepancies are still not yet settled. For further investigations and definite conclusions an improvement of the theoretical precision as well as the experimental one is mandatory. Communicated by Professor Alan Martin (topical review)

  6. Novel structured emulsions for delivering of food flavours

    Mao, Like

    2014-01-01

    Flavour release from food is determined by the binding of flavours to other food ingredients and the partition of flavour molecules among different phases. Food emulsions are used as delivery systems for food flavours, and tailored structuring in emulsions provides novel means to better control flavour release. The current study investigated four structured oil-in-water emulsions with structuring in the oil phase, oil-water interface, and water phase. Oil phase structuring was achieved by the...

  7. Strong color fields and heavy flavour production

    The clustering of color sources provides a natural framework of partonic interactions producing strong color fields. We study the consequences of these color fields in the production of heavy flavour and in the behavior of the nuclear modified factor.

  8. Flavour models with Dirac and fake gluinos

    In the context of supersymmetric models where the gauginos may have both Majorana and Dirac masses we investigate the general constraints from flavour-changing processes on the scalar mass matrices. One finds that the chirality-flip suppression of flavour-changing effects usually invoked in the pure Dirac case holds in the mass insertion approximation but not in the general case, and fails in particular for inverted hierarchy models. We quantify the constraints in several flavour models which correlate fermion and scalar superpartner masses. We also discuss the limit of very large Majorana gaugino masses compared to the chiral adjoint and Dirac masses, where the remaining light eigenstate is the “fake” gaugino, including the consequences of suppressed couplings to quarks beyond flavour constraints

  9. Heavy flavour hadron spectroscopy: An overview

    P C Vinodkumar

    2014-11-01

    A comprehensive overview and some of the theoretical attempts towards understanding heavy flavour hadron spectroscopy are presented. Apart from the conventional quark structure (quark, antiquarks structure for the mesons and three-quarks structure of baryons) of hadrons, multiquark hadrons the hadron molecular states etc., also will be reviewed. Various issues and challenges in understanding the physics and dynamics of the quarks at the hadronic dimensions are highlighted. Looking into the present and future experimental prospects at different heavy flavour laboratories like BES-III, CLEO-c, BaBar, Belle, LHC etc., the scope for theoretical extensions of the present knowledge of heavy flavour physics would be very demanding. In this context, many relevant contributions from the forthcoming PANDA Facility are expected. Scopes and outlook of the hadron physics at the heavy flavour sector in view of the future experimental facilities are highlighted.

  10. Dynamics of Non-supersymmetric Flavours

    Alam, M Sohaib; Kundu, Arnab; Kundu, Sandipan

    2013-01-01

    We continue investigating the effect of the back-reaction by non-supersymmetric probes in the Kuperstein-Sonnenschein model. In the limit when the back-reaction is small, we discuss physical properties of the back-reacted geometry. We further introduce additional probe flavours in this back-reacted geometry and study in detail the phase structure of this sector when a constant electromagnetic field or a chemical potential are present. We find that the Landau pole, which serves as the UV cut-off of the background geometry, also serves as an important scale in the corresponding thermodynamics of the additional flavour sector. We note that since this additional probe flavours are indistinguishable from the back-reacting flavours, the results we obtain point to a much richer phase structure of the system.

  11. b-flavour tagging in pp collisions

    Birnkraut, Alex

    2015-01-01

    An essential ingredient of all time-dependent CP violation studies of B mesons is the ability to tag the initial flavour of the B meson. The harsh environment of 7 and 8 TeV pp collisions makes this a particularly difficult enterprise. We report progresses in the flavour tagging of B0 and Bs mesons, including developments of novel techniques like the use of an opposite side charm tagger.

  12. Flavour Violation in Anomaly Mediated Supersymmetry Breaking

    Allanach, B. C.; Hiller, G; Jones, D. R. T.; Slavich, P.(LPTHE, UPMC Univ. Paris 06, Sorbonne Universités, 4 Place Jussieu, 75252, Paris, France)

    2009-01-01

    32 pages, 8 figures International audience We study squark flavour violation in the anomaly mediated supersymmetry broken (AMSB) minimal supersymmetric standard model. Analytical expressions for the three-generational squark mass matrices are derived. We show that the anomaly-induced soft breaking terms have a decreasing amount of squark flavour violation when running from the GUT to the weak scale. Taking into account inter-generational squark mixing, we work out non-trivial constraint...

  13. Spontaneous CP symmetry violation in electroweak theories

    The phenomenon of CP symmetry violation is reviewed with reference to the neutral kaon systems and its realization as manifest, or a spontaneous breaking in the context of electroweak gauge theories is discussed. It is shown that, as in the standard electroweak model, spontaneous CP violation can be achieved in the left-right symmetric and partially ununified models through extension of the Higgs sector and inclusion of an appropriate discrete symmetry. The experimental constraints on flavour changing neutral current in these models are also discussed. (author). 25 refs., 2 figs

  14. Thermodynamics of lattice QCD with 3 flavours of colour-sextet quarks

    Kogut, J B

    2011-01-01

    We have been studying QCD with 2 flavours of colour-sextet quarks to distinguish whether it is QCD-like or conformal. For comparison we are now studying QCD with 3 flavours of colour-sextet quarks, which is believed to be conformal in the chiral limit. Here we present the results of simulations of lattice QCD with 3 colour-sextet quarks at finite temperatures on lattices of temporal extent $N_t=4$ and 6, with masses small enough to yield access to the chiral limit. As for the 2-flavour case, we find well-separated deconfinement and chiral-symmetry restoration transitions, both of which move to appreciably weaker couplings as $N_t$ is increased from 4 to 6. If this theory is conformal, we would expect there to be a bulk chiral transition at a fixed coupling. For this reason we conclude that for $N_t=4$ and 6, the chiral and hence the deconfinement transitions are in the strong-coupling domain where the theory is essentially quenched. The similarity between the behaviours of the 2 and 3 flavour theories suggest...

  15. Heavy Flavour production in ATLAS

    ATLAS prepared a program for measurements of production cross sections both of b-hadrons and Onia in central proton-proton collisions at new energy 14 TeV of LHC. Dedicated triggers based on muon, di-muon or electron signatures are designed to accommodate large statistics with already first several months. Starting from semi-inclusive measurements for very early stage exclusive channels will soon dominate measurements, allowing tests of QCD in Heavy Flavour sector already with 10 pb-1. With larger statistics production polarization measurements are being prepared for J/ψ and Λb. It is expected that 30 fb-1 collected at 1033cm-2 s-1 will allow specific measurements not accessible with limited statistics of Tevatron. In particular b polarization measurement can be achieved using Λb → J/ψ Λ decay. In J/ψ a polarization measurement will allow to confirm or exclude model predictions within large interval of transverse momenta. (author)

  16. Seiberg duality versus hidden local symmetry

    Abel, Steven

    2012-01-01

    It is widely believed that the emergent magnetic gauge symmetry of SQCD is analogous to a hidden local symmetry (HLS). We explore this idea in detail, deriving the entire (spontaneously broken) magnetic theory by applying the HLS formalism to spontaneously broken SU(N) SQCD. We deduce the K\\"ahler potential in the HLS description, and show that gauge and flavour symmetry are smoothly restored along certain scaling directions in moduli space. We propose that it is these symmetry restoring directions, associated with the R-symmetry of the theory, that allow full Seiberg duality. Reconsidering the origin of the magnetic gauge bosons as the rho-mesons of the electric theory, colour-flavour locking allows a simple determination of the parameter "a". Its value continuously interpolates between a=2 on the baryonic branch of moduli space - corresponding to "vector meson dominance" - and a=1 on the mesonic branch. Both limiting values are consistent with previous results in the literature. The HLS formalism is further...

  17. Release of peppermint flavour compounds from chewing gum: effect of oral functions

    Haahr, Anne-Mette; Bardow, A.; Thomsen, C.E.;

    2004-01-01

    During chewing, the oral cavity functions like a bellow, forcing volatile flavour compounds into the exhaling air to the nasal compartment. Accordingly, we hypothesised that flavour release from chewing gum is predominantly governed by chewing frequency (CF), although other oral functions, like...... masseter muscle activity (MMA), chewing force (CFO), and saliva flow rate (SFR), may also play a role. In 10 healthy young males, the retronasal expired air of menthol and menthone from peppermint-flavoured (2%) chewing gum was determined as functions of CF, SFR, MMA, and CFO. The experimental setup...... comprised three separate series of a 4-min chewing period. These series differed only with respect to CF, i.e., habitual frequency, and 60 and 88 strokes/min. Results showed that more than 50% of the released menthol and menthone could be retrieved in the expired air and saliva. After 2-min of chewing, the...

  18. The supersymmetric flavour problem in 5D GUTs and its consequences for LHC phenomenology

    We study supersymmetric models with a GUT-sized extra dimension, where both the Higgs fields and the SUSY breaking hidden sector are localized on a 4D brane. Exponential wave function profiles of the matter fields give rise to hierarchical structures in the Yukawa couplings and soft terms. Such structures can naturally explain hierarchical fermion masses and mixings, while at the same time alleviating the supersymmetric flavour problem. We discuss two sources of supersymmetry breaking, radion mediation and brane fields, and perform a detailed numerical analysis, thoroughly taking into account the proliferation of unknown O(1) coefficients that occurs in this class of models. It turns out that additional assumptions on supersymmetry breaking are necessary to evade the stringent experimental bounds on lepton flavour violation. The favourable regions of parameter space are then examined with regards to their LHC phenomenology. They generically feature heavy gluinos and squarks beyond current bounds. Lepton flavour violation in SUSY cascade decays can give interesting signatures. (orig.)

  19. The supersymmetric flavour problem in 5D GUTs and its consequences for LHC phenomenology

    Bruemmer, F. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Fichet, S.; Kraml, S. [CNRS/IN2P3, Grenoble (France). Lab. de Physique Subatomique et de Cosmologie

    2011-09-15

    We study supersymmetric models with a GUT-sized extra dimension, where both the Higgs fields and the SUSY breaking hidden sector are localized on a 4D brane. Exponential wave function profiles of the matter fields give rise to hierarchical structures in the Yukawa couplings and soft terms. Such structures can naturally explain hierarchical fermion masses and mixings, while at the same time alleviating the supersymmetric flavour problem. We discuss two sources of supersymmetry breaking, radion mediation and brane fields, and perform a detailed numerical analysis, thoroughly taking into account the proliferation of unknown O(1) coefficients that occurs in this class of models. It turns out that additional assumptions on supersymmetry breaking are necessary to evade the stringent experimental bounds on lepton flavour violation. The favourable regions of parameter space are then examined with regards to their LHC phenomenology. They generically feature heavy gluinos and squarks beyond current bounds. Lepton flavour violation in SUSY cascade decays can give interesting signatures. (orig.)

  20. A Grand {Delta}(96) Multiplication-Sign SU(5) Flavour Model

    King, Stephen F., E-mail: king@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom); Luhn, Christoph, E-mail: christoph.luhn@durham.ac.uk [Institute for Particle Physics Phenomenology, University of Durham, Durham, DH1 3LE (United Kingdom); Stuart, Alexander J., E-mail: a.stuart@soton.ac.uk [School of Physics and Astronomy, University of Southampton, Southampton, SO17 1BJ (United Kingdom)

    2013-02-11

    Recent results from the Daya Bay and RENO reactor experiments have measured the smallest lepton mixing angle and found it to have a value of {theta}{sub 13} Almost-Equal-To 9 Degree-Sign . This result presents a new challenge for the existing paradigms of discrete flavour symmetries which attempt to describe all quark and lepton masses and mixing angles. Here we propose a Supersymmetric Grand Unified Theory of Flavour based on {Delta}(96) Multiplication-Sign SU(5), together with a U(1) Multiplication-Sign Z{sub 3} symmetry, including a full discussion of {Delta}(96) in a convenient basis. The Grand {Delta}(96) Multiplication-Sign SU(5) Flavour Model relates the quark mixing angles and masses in the form of the Gatto-Sartori-Tonin relation and realises the Georgi-Jarlskog mass relations between the charged leptons and down-type quarks. We predict a Bi-trimaximal (not Tri-bimaximal) form of neutrino mixing matrix, which, after including charged lepton corrections with zero phase, leads to the following GUT scale predictions for the atmospheric, solar, and reactor mixing angles: {theta}{sub 23} Almost-Equal-To 36.9 Degree-Sign , {theta}{sub 12} Almost-Equal-To 32.7 Degree-Sign and {theta}{sub 13} Almost-Equal-To 9.6 Degree-Sign , in good agreement with recent global fits, and a zero Dirac CP phase {delta} Almost-Equal-To 0.

  1. Flavour in the era of the LHC

    2006-01-01

    The 4th meeting of the 'Flavour in the era of the LHC'workshop will take place at CERN on 9-11 October, 2006. The goal of this workshop is to outline and document a programme for flavour physics for the next decade, addressing in particular the complementarity and synergy between the discoveries we expect to emerge from the LHC and the potential for accurate measurements of future flavour factories. Over 150 physicists will join in the discussions of the three working groups dedicated to 'Flavour physics at high Q', 'B/D/K decays'and 'Flavour in the lepton sector, EDM's, g-2, etc'. The previous meetings took place in November 2005, and in February and May this year. In addition to the working group sessions, a special miniworkshop dedicated to future prospects for electric dipole moment (EDM) searches and g-2 measurements will be held on 9-10 October. Sensitive EDM and g-2 experiments probe physics in an integral way, and in many cases their physics reach is much higher than the spectrometer searches at th...

  2. Flavour in the era of the LHC

    2006-01-01

    The 4th meeting of the 'Flavour in the era of the LHC' workshop will take place at CERN on 9-11 October, 2006. The goal of this workshop is to outline and document a programme for flavour physics for the next decade, addressing in particular the complementarity and synergy between the discoveries we expect to emerge from the LHC and the potential for accurate measurements of future flavour factories. Over 150 physicists will join in the discussions of the three working groups dedicated to 'Flavour physics at high Q', 'B/D/K decays' and 'Flavour in the lepton sector, EDM's, g-2, etc'. The previous meetings took place in November 2005, and in February and May this year. In addition to the working group sessions, a special miniworkshop dedicated to future prospects for electric dipole moment (EDM) searches and g-2 measurements will be held on 9-10 October. Sensitive EDM and g-2 experiments probe physics in an integral way, and in many cases their physics reach is much higher than the spectrometer searches at th...

  3. Minimal flavour violation and SU(5)-unification

    Barbieri, Riccardo, E-mail: barbieri@sns.it; Senia, Fabrizio, E-mail: fabrizio.senia@sns.it [Scuola Normale Superiore and INFN, Piazza dei Cavalieri 7, 56126, Pisa (Italy)

    2015-12-17

    Minimal flavour violation in its strong or weak versions, based on U(3){sup 3} and U(2){sup 3}, respectively, allows suitable extensions of the standard model at the TeV scale to comply with current flavour constraints in the quark sector. Here we discuss considerations analogous to minimal flavour violation (MFV) in the context of SU(5)-unification, showing the new effects/constraints that arise both in the quark and in the lepton sector, where quantitative statements can be made controlled by the CKM matrix elements. The case of supersymmetry is examined in detail as a particularly motivated example. Third generation sleptons and neutralinos in the few hundred GeV range are shown to be compatible with current constraints.

  4. Minimal flavour violation and SU(5)-unification

    Barbieri, Riccardo; Senia, Fabrizio [Scuola Normale Superiore, Pisa (Italy); INFN, Pisa (Italy)

    2015-12-15

    Minimal flavour violation in its strong or weak versions, based on U(3){sup 3} and U(2){sup 3}, respectively, allows suitable extensions of the standard model at the TeV scale to comply with current flavour constraints in the quark sector. Here we discuss considerations analogous to minimal flavour violation (MFV) in the context of SU(5)-unification, showing the new effects/constraints that arise both in the quark and in the lepton sector, where quantitative statements can be made controlled by the CKM matrix elements. The case of supersymmetry is examined in detail as a particularly motivated example. Third generation sleptons and neutralinos in the few hundred GeV range are shown to be compatible with current constraints. (orig.)

  5. Minimal flavour violation and SU(5)-unification

    Minimal flavour violation in its strong or weak versions, based on U(3)3 and U(2)3, respectively, allows suitable extensions of the standard model at the TeV scale to comply with current flavour constraints in the quark sector. Here we discuss considerations analogous to minimal flavour violation (MFV) in the context of SU(5)-unification, showing the new effects/constraints that arise both in the quark and in the lepton sector, where quantitative statements can be made controlled by the CKM matrix elements. The case of supersymmetry is examined in detail as a particularly motivated example. Third generation sleptons and neutralinos in the few hundred GeV range are shown to be compatible with current constraints. (orig.)

  6. Study of baryon number and lepton flavour violation in the new minimal supersymmetric SO(10)GUT

    Kaur, Charanjit

    2015-01-01

    We study the so-called new minimal supersymmetric SO(10) GUT(NMSGUT) where explicit spontaneous symmetry breaking allows determination of superheavy spectrum and thus threshold corrections to the effective MSSM couplings. This provides a generic mechanism to resolve the long standing super fast proton decay in Susy GUTs. We estimate lepton flavor violation associated with realistic charged fermion and (Type I seesaw) neutrino fit and show compatibility with baryon number and lepton flavour violation limits. We improve NMSGUT fits by including important loop corrections to sparticle spectra. Our fits use 5 GUT compatible soft supersymmetry breaking parameters of the Supergravity with Non-Universal Higgs Masses(SUGRY-NUHM) type. We calculate the full two loop NMSGUT gauge-Yukawa beta functions to study feasibility of the NUHM parameters via strong renormalization of SO(10) Higgs soft masses. Focus on MSSM Higgs allows formulation of a "Yukawonification" strategy for gauged flavour unification.

  7. Generalised geometrical CP violation in a T′ lepton flavour model

    We analyse the interplay of generalised CP transformations and the non-Abelian discrete group T′ and use the semi-direct product Gf=T′⋊HCP, as family symmetry acting in the lepton sector. The family symmetry is shown to be spontaneously broken in a geometrical manner. In the resulting flavour model, naturally small Majorana neutrino masses for the light active neutrinos are obtained through the type I see-saw mechanism. The known masses of the charged leptons, lepton mixing angles and the two neutrino mass squared differences are reproduced by the model with a good accuracy. The model allows for two neutrino mass spectra with normal ordering (NO) and one with inverted ordering (IO). For each of the three spectra the absolute scale of neutrino masses is predicted with relatively small uncertainty. The value of the Dirac CP violation (CPV) phase δ in the lepton mixing matrix is predicted to be δ≅π/2 or 3π/2. Thus, the CP violating effects in neutrino oscillations are predicted to be maximal (given the values of the neutrino mixing angles) and experimentally observable. We present also predictions for the sum of the neutrino masses, for the Majorana CPV phases and for the effective Majorana mass in neutrinoless double beta decay. The predictions of the model can be tested in a variety of ongoing and future planned neutrino experiments

  8. LHCb New algorithms for Flavour Tagging at the LHCb experiment

    Fazzini, Davide

    2016-01-01

    The Flavour Tagging technique allows to identify the B initial flavour, required in the measurements of flavour oscillations and time-dependent CP asymmetries in neutral B meson systems. The identification performances at LHCb are further enhanced thanks to the contribution of new algorithms.

  9. Heavy Flavour Production and Decay at ATLAS

    Jones, RWL; The ATLAS collaboration

    2013-01-01

    ATLAS is taking advantage of its large integrated luminosity band sophisticated muon and dimuon triggers to make competitive measurements of heavy flavour production and decay. Inclusive production and heavy flavour jet production is discussed before turning to charm and onium production. The production and decay of individual B hadron species is then addressed, including the current best measurement of the Λb lifetime. A much improved analysis of CP related quantities in Bs decays is presented, before turning to recent results and prospects for rare B decays.

  10. SU(3) flavour breaking and baryon structure

    Cooke, A.N.; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe, Hyogo (Japan); Pleiter, D. [Forschungszentrum Juelich GmbH (Germany). Juelich Supercomputing Centre (JSC); Regensburg Univ. (Germany). Institut fuer Theoretische Physik; Rakow, P.E.L. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Shanahan, P.; Zanotti, J.M. [Adelaide Univ., SA (Australia). CSSM, School of Chemistry and Physics; Schierholz, G. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Stueben, H. [Hamburg Univ. (Germany). Regionales Rechenzentrum; Collaboration: QCDSF/UKQCD Collaboration

    2013-11-15

    We present results from the QCDSF/UKQCD collaboration for hyperon electromagnetic form factors and axial charges obtained from simulations using N{sub f}=2+1 flavours of O(a)-improved Wilson fermions. We also consider matrix elements relevant for hyperon semileptonic decays. We find flavour-breaking effects in hyperon magnetic moments which are consistent with experiment, while our results for the connected quark spin content indicates that quarks contribute more to the spin of the {Xi} baryon than they do to the proton.

  11. Higgs-mediated FCNCs: Natural Flavour Conservation vs. Minimal Flavour Violation

    Buras, Andrzej J; Gori, Stefania; Isidori, Gino

    2010-01-01

    We compare the effectiveness of two hypotheses, Natural Flavour Conservation (NFC) and Minimal Flavour Violation (MFV), in suppressing the strength of flavour-changing neutral-currents (FCNCs) in models with more than one Higgs doublet. We show that the MFV hypothesis, in its general formulation, is more stable in suppressing FCNCs than the hypothesis of NFC alone when quantum corrections are taken into account. The phenomenological implications of the two scenarios are discussed analysing meson-antimeson mixing observables and the rare decays B -> mu+ mu-. We demonstrate that, introducing flavour-blind CP phases, two-Higgs doublet models respecting the MFV hypothesis can accommodate a large CP-violating phase in Bs mixing, as hinted by CDF and D0 data and, without extra free parameters, soften significantly in a correlated manner the observed anomaly in the relation between epsilon_K and S_psi_K.

  12. General squark flavour mixing: constraints, phenomenology and benchmarks

    De Causmaecker, Karen; Herrmann, Bjoern; Mahmoudi, Farvah; O'Leary, Ben; Porod, Werner; Sekmen, Sezen; Strobbe, Nadja

    2015-01-01

    We present an extensive study of non-minimal flavour violation in the squark sector in the framework of the Minimal Supersymmetric Standard Model. We investigate the effects of multiple non-vanishing flavour-violating elements in the squark mass matrices by means of a Markov Chain Monte Carlo scanning technique and identify parameter combinations that are favoured by both current data and theoretical constraints. We then detail the resulting distributions of the flavour-conserving and flavour-violating model parameters. Based on this analysis, we propose a set of benchmark scenarios relevant for future studies of non-minimal flavour violation in the Minimal Supersymmetric Standard Model.

  13. Sweetness flavour interactions in soft drinks.

    Nahon, D.F.; Roozen, J.P.; Graaf, de C.

    1996-01-01

    Sucrose can be substituted by intense sweeteners to lower the calorie content of soft drinks. Although the sweetness is kept at the same level as much as possible, the flavour of the product often changes. This change could be due to both the mechanism of sensory perception and interactive effects o

  14. Heavy flavour physics at the LHC

    A summary of results in heavy flavour physics from Run 1 of the LHC is presented. Topics discussed include spectroscopy, mixing, CP violation and rare decays of charmed and beauty hadrons. The results are consistent with Standard Model predictions, although several puzzles and hints of discrepancies demand further investigation with larger data samples

  15. Working group report: Collider and flavour physics

    Debajyoti Choudhury; Asesh K Datta; Anirban Kundu

    2009-01-01

    The activities of the working group took place under two broad subgroups: Collider Physics subgroup and Flavour Physics subgroup. Reports on some of the projects undertaken are included. Also, some of the leading discussions organized by the working group are summarized.

  16. Search for new flavour production at PETRA

    The topological distribution of hadrons from the reaction e+e- → multihadrons has been studied at PETRA energies between √ s = 22 and 31.6 GeV. No evidence is seen for spherical events which would be expected if massive particles bearing new flavours were produced. (orig.)

  17. Minimal flavour violation and beyond: Towards a flavour code for short distance dynamics

    Buras, Andrzej J

    2010-01-01

    This decade should provide the first definitive signals of New Physics (NP) beyond the Standard Model (SM) and the goal of these lectures is a review of flavour physics in various extensions of the SM that have been popular in the last ten years. After an overture, two pilot sections and a brief summary of the structure of flavour violation and CP violation in the SM, we will present the theoretical framework for weak decays that will allow us to distinguish between different NP scenarios. Subsequently we will present twelve concrete BSM models summarizing the patterns of flavour violation characteristic for each model. In addition to models with minimal flavour violation (MFV) accompanied by flavour blind phases we will discuss a number of extensions containing non-MFV sources of flavour and CP violation and, in particular, new local operators originating in right-handed charged currents and scalar currents. Next we will address various anomalies in the data as seen from the point of view of the SM that appe...

  18. Cern Academic Training programme 2011 - Flavour Physics and CP Violation

    PH Department

    2011-01-01

    LECTURE SERIES   4, 5, 6 and 7 April 2011 Flavour Physics and CP Violation Dr. Yosef Nir (Weizmann Institute of Science, Rehovot, Israel 11:00-12:00 - 4, 6 and 7 April - Bldg. 222-R-001 - Filtration Plant 5 April - Bldg. 80-1-001 - Globe 1st Floor   The B-factories have led to significant progress in our understanding of CP violation and of flavour physics. Yet, two flavour puzzles remain. The standard model flavour puzzle is the question of why there is smallness and hierarchy in the flavour parameters. The new physics flavour puzzle is the question of why TeV-scale new physics was not signalled in flavour changing neutral current processes. The high pT experiments, ATLAS and CMS, are likely to shed light on these puzzles. As concerns CP violation, the LHC will lead to progress on the puzzle of the baryon asymmetry as well.  

  19. A flavour physics scenario for the 750 GeV diphoton anomaly

    Bonilla, Cesar; Srivastava, Rahul; Valle, Jose W F

    2016-01-01

    A simple variant of a realistic flavour symmetry scheme for fermion masses and mixings provides a possible interpretation of the diphoton anomaly as an electroweak singlet "flavon". The existence of TeV scale vector-like T-quarks required to provide adequate values for CKM parameters can also naturally account for the diphoton anomaly. Correlations between $V_{ub}$ and $V_{cb}$ with the vector-like T-quark mass can be predicted. Should the diphoton anomaly survive in a future Run, our proposed interpretation can also be tested in upcoming B and LHC studies.

  20. Relic neutrino decoupling including flavour oscillations

    Mangano, Gianpiero [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Department of Physics, Syracuse University, Syracuse, NY 13244-1130 (United States); Miele, Gennaro [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Pastor, Sergio [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Ed. Institutos de Investigacion, Apdo. 22085, E-46071 Valencia (Spain)]. E-mail: pastor@ific.uv.es; Pinto, Teguayco [Instituto de Fisica Corpuscular (CSIC-Universitat de Valencia), Ed. Institutos de Investigacion, Apdo. 22085, E-46071 Valencia (Spain); Pisanti, Ofelia [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II and INFN, Sezione di Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Naples (Italy); Serpico, Pasquale D. [Max-Planck-Institut fuer Physik (Werner-Heisenberg-Institut), Foehringer Ring 6, D-80805 Munich (Germany)

    2005-11-21

    In the early universe, neutrinos are slightly coupled when electron-positron pairs annihilate transferring their entropy to photons. This process originates non-thermal distortions on the neutrino spectra which depend on neutrino flavour, larger for {nu}{sub e} than for {nu}{sub {mu}} or {nu}{sub {tau}}. We study the effect of three-neutrino flavour oscillations on the process of neutrino decoupling by solving the momentum-dependent kinetic equations for the neutrino spectra. We find that oscillations do not essentially modify the total change in the neutrino energy density, giving N{sub eff}=3.046 in terms of the effective number of neutrinos, while the small effect over the production of primordial {sup 4}He is increased by O(20%), up to 2.1x10{sup -4}. These results are stable within the presently favoured region of neutrino mixing parameters.

  1. Neutrino observables from predictive flavour patterns

    Cebola, Luis M.; Emmanuel-Costa, David [Universidade de Lisboa, Departamento de Fisica and Centro de Fisica Teorica de Particulas - CFTP, Instituto Superior Tecnico, Lisboa (Portugal); Felipe, Ricardo Gonzalez [Universidade de Lisboa, Departamento de Fisica and Centro de Fisica Teorica de Particulas - CFTP, Instituto Superior Tecnico, Lisboa (Portugal); ISEL - Instituto Superior de Engenharia de Lisboa, Instituto Politecnico de Lisboa, Lisboa (Portugal)

    2016-03-15

    We look for predictive flavour patterns of the effective Majorana neutrino mass matrix that are compatible with current neutrino oscillation data. Our search is based on the assumption that the neutrino mass matrix contains equal elements and a minimal number of parameters, in the flavour basis where the charged lepton mass matrix is diagonal and real. Three unique patterns that can successfully explain neutrino observables at the 3σ confidence level with just three physical parameters are presented. Neutrino textures described by four and five parameters are also studied. The predictions for the lightest neutrino mass, the effective mass parameter in neutrinoless double beta decays and for the CP-violating phases in the leptonic mixing are given. (orig.)

  2. Neutrino observables from predictive flavour patterns

    Cebola, Luis M; Felipe, Ricardo Gonzalez

    2016-01-01

    We look for predictive flavour patterns of the effective Majorana neutrino mass matrix that are compatible with current neutrino oscillation data. Our search is based on the assumption that the neutrino mass matrix contains equal elements and a minimal number of parameters, in the flavour basis where the charged lepton mass matrix is diagonal and real. Three unique patterns that can successfully explain neutrino observables at the $3\\sigma$ confidence level with just three physical parameters are presented. Neutrino textures described by four and five parameters are also studied. The predictions for the lightest neutrino mass, the effective mass parameter in neutrinoless double beta decays and the CP-violating phases in the leptonic mixing are given.

  3. Heavy flavour physics from top to bottom

    Paulini, M. [Lawrence Berkeley National Lab., CA (United States); CDF and D0 Collaborations

    1997-01-01

    We review the status of heavy flavour physics at the Fermilab Tevatron collider by summarizing recent top quark and B physics results from CDF and D0. In particular we discuss the measurement of the top quark mass and top production cross section as well as B meson lifetimes and time dependent B{bar B} mixing results. An outlook of perspectives for top and B physics in Run II starting in 1999 is also given. 38 refs., 23 figs., 8 tabs.

  4. Flavour democracy calls for the fourth generation

    It is argued with the help of an illustrative mode, that the inter species hierarchy among the fermion masses and the quark mixing angles can be accommodated naturally in the standard model with (approximate) flavour democracy provided there are four families of sequential quark-leptons with all members of the fourth family having roughly equal masses. The special problem of light neutrino masses (if any) and possible solutions are also discussed. (author). 15 refs

  5. Flavour of fundamental particles and prime numbers

    The discreteness and continuity as described by the ratio of the discreteness of the n's and the continuous spread of n/2n, which is directly connected with the width and lifetimes of fundamental particles, the flavours of fundamental particles can be directly obtained. The behaviour of beta decay and the energy levels of light nuclei can also be predicted. The appearance of primes also seems to suggest that further application of reductionism to fundamental particles is not possible

  6. Some theoretical issues in heavy flavour physics

    Amol Dighe

    2012-11-01

    Some of the recent developments in heavy flavour physics will be reviewed. This will include an update on some of the Standard Model predictions, and a summary of recent measurements that may indicate the presence of new physics (NP). The focus will be on selected models of NP that are indicated by the anomalies in the current data. Observables that can potentially yield signatures of specific physics beyond the Standard Model will be pointed out.

  7. Creating innovative flavour and texture experiences

    Edwards-Stuart, Rachel

    2009-01-01

    The work presented in this thesis describes the use of scientific research in the development of novel texture and flavour experiences and their potential for use in fine gastronomy. In order to create an interesting textural experience, modified celluloses were investigated. Their unique property is that they have the ability to gel at high temperatures, but return to the solution state upon cooling. This phenomena was used to test the hypothesis that hot gels made from these materials could...

  8. Including heavy flavour production in PDF fits

    A.M. Cooper-Sarkar

    2007-01-01

    AT HERA heavy quarks may contribute up to 30% of the structure function $F_2$. The introduction of heavy quarks requires an extension of the DGLAP formalism. The effect of using different heavy flavour number schemes, and different approaches to the running of $\\alpha_s$, are compared using the ZEUS PDF fit formalism. The potential of including charm data in the fit is explored, using $D^*$ double differential cross-sections rather than the inclusive quantity $F_2^{c\\bar{c}}$.

  9. Effects of flavour absorption on foods and their packaging materials

    Willige, van, R.W.G.

    2002-01-01

    Keywords: flavour absorption, scalping, packaging, food matrix, lldpe, ldpe, pp, pc, pet, pen,b-lactoglobulin, casein, pectin, cmc, lactose, saccharose, oil, modelling, storage, oxygen permeability, taste perception, sensory quality.Absorption of flavour compounds by linear low-density polyethylene (LLDPE) was studied in model systems representing differences in composition of the food matrix. Proteins,b-lactoglobuline and casein, were able to bind flavours, resulting in suppression of absorp...

  10. Inherited Symmetry

    Attanucci, Frank J.; Losse, John

    2008-01-01

    In a first calculus course, it is not unusual for students to encounter the theorems which state: If f is an even (odd) differentiable function, then its derivative is odd (even). In our paper, we prove some theorems which show how the symmetry of a continuous function f with respect to (i) the vertical line: x = a or (ii) with respect to the…

  11. Chiral symmetry

    We present many varied chiral symmetry models at the quark level which consistently describe strong interaction hadron dynamics. The pattern that emerges is a nonstrange current quark mass scale mcur ≅ (34-69) MeV and a current quark mass ratio (ms/m)cur ≅ 5-6 along with no strange quark content in nucleons. (orig./WL)

  12. Flavour tagging of $b$ mesons in $pp$ collisions at LHCb

    Mueller, Vanessa

    2016-01-01

    Flavour tagging, i.e. the inference of the production flavour of reconstructed $b$ hadrons, is essential for precision measurements of decay time-dependent $CP$ violation and of mixing parameters in the the neutral $B$ meson systems. LHC's $pp$ collisions with their high track multiplicities constitute a challenging environment for flavour tagging and demand for new and improved strategies. We present recent progress and new developments in flavour tagging at the LHCb experiment, which will allow for a further improvement of $CP$ violation measurements in decays of $B^0$ and $B_s^0$ mesons.

  13. Leptonic minimal flavour violation in warped extra dimensions

    Abhishek M Iyer; Sudhir K Vempati

    2012-10-01

    Lepton mass hierarchies and lepton flavour violation are revisited in the framework of Randall–Sundrum models. Models with Dirac-type as well as Majorana-type neutrinos are considered. The five-dimensional -parameters are fit to the charged lepton and neutrino masses and mixings using 2 minimization. Leptonic flavour violation is shown to be large in these cases. Schemes of minimal flavour violation are considered for the cases of an effective LLHH operator and Dirac neutrinos and are shown to significantly reduce the limits from lepton flavour violation.

  14. LIE SYMMETRIES AND NOETHER SYMMETRIES

    PGL Leach

    2012-10-01

    Full Text Available We demonstrate that so-called nonnoetherian symmetries with which a known first integral is associated of a differential equation derived from a Lagrangian are in fact noetherian. The source of the misunderstanding lies in the nonuniqueness of the Lagrangian.

  15. Symmetry, Symmetry Breaking and Topology

    Siddhartha Sen

    2010-07-01

    Full Text Available The ground state of a system with symmetry can be described by a group G. This symmetry group G can be discrete or continuous. Thus for a crystal G is a finite group while for the vacuum state of a grand unified theory G is a continuous Lie group. The ground state symmetry described by G can change spontaneously from G to one of its subgroups H as the external parameters of the system are modified. Such a macroscopic change of the ground state symmetry of a system from G to H correspond to a “phase transition”. Such phase transitions have been extensively studied within a framework due to Landau. A vast range of systems can be described using Landau’s approach, however there are also systems where the framework does not work. Recently there has been growing interest in looking at such non-Landau type of phase transitions. For instance there are several “quantum phase transitions” that are not of the Landau type. In this short review we first describe a refined version of Landau’s approach in which topological ideas are used together with group theory. The combined use of group theory and topological arguments allows us to determine selection rule which forbid transitions from G to certain of its subgroups. We end by making a few brief remarks about non-Landau type of phase transition.

  16. Universe symmetries

    The sky uniformity can be noticed in studying the repartition of objects far enough. The sky isotropy description uses space rotations. The group theory elements will allow to give a meaning at the same time precise and general to the word a ''symmetry''. Universe models are reviewed, which must have both of the following qualities: - conformity with the physic known laws; - rigorous symmetry following one of the permitted groups. Each of the models foresees that universe evolution obeys an evolution equation. Expansion and big-bang theory are recalled. Is universe an open or closed space. Universe is also electrically neutral. That leads to a work hypothesis: the existing matter is not given data of universe but it appeared by evolution from nothing. Problem of matter and antimatter is then raised up together with its place in universe

  17. Flavouring compounds in Indian potato snacks.

    Raigond, Pinky; Singh, Brajesh; Dhulia, Akshita; Chopra, Shelly; Dutt, Som

    2015-12-01

    Market for processed potato products is rising day by day. Flavour plays important role in decision making by consumers due to their preferences for better tasting food. In potato and potato products, glutamic acid, aspartic acid, guanosine 5'-monophosphate (GMP) and adenosine 5'-monophosphate (AMP) are the major umami compounds which contribute towards flavour. Therefore, umami 5' nucleotides (AMP+GMP) were estimated from local potato products available as common fried products in the Indian markets and processed potato products being sold by the retailers. The analysis was also carried in raw, microwaved and pressure cooked tubers of forty seven Indian potato cultivars. Umami 5' nucleotide content ranged from 2.63 (Aloo seekh) to 8.26 μg/g FW (fried lachcha) in local potato products. In processed potato products, the content ranged from 2.72 μg/g FW (Smiles) to 14.75 μg/g FW (Aloo Bhujia). Along with aloo bhujia, umami 5' nucleotides were also high in dehydrated aloo lachcha (11.14 μg/g FW) and dehydrated potato chips (10.13 μg/g FW) and low in Smiles (2.72 μg/g FW) and Potato Shortz (3.40 μg/g FW). The study suggests that the potato products prepared solely from potato contained higher levels of umami 5' nucleotides compared to other products prepared by mixing potato with other cereals and vegetables. In Indian potato cultivars overall there was 14 % increase on microwave cooking and 31 % increase in flavouring compounds on pressure cooking. This type of study enabled in identifying better tasting cultivars for further product development and also to develop products with less addition of salt. PMID:26604408

  18. Flavour perception of oxidation in beef.

    Campo, M M; Nute, G R; Hughes, S I; Enser, M; Wood, J D; Richardson, R I

    2006-02-01

    Lipid oxidation is a major factor in meat quality. In order to relate human perceptions of lipid oxidation, as determined by a trained taste panel, to a chemical measurement of oxidation, we studied meat from animals with a wide range of potential oxidation through differences in their PUFA composition and by displaying the meat in high oxygen modified atmosphere packs for varying lengths of time. Meat was obtained from 73 Angus- and Charolais-cross steers from different trials that had been raised on 10 different diets: grass silage (high in C18:3, n-3), cereal concentrate (high in C18:2, n-6), three diets with 3% added fat consisting of three levels of protected lipid supplement (high in C18:2, n-6 and C18:3, n-3, ratio 1:1), a control with Megalac(®) (relatively saturated), three diets with three levels of inclusion of protected fish oil (high in C20:5 n-3 and C22:6 n-3) plus a constant amount of unprotected fish oil and a final diet with an unprotected fish oil control. The longissimus dorsi muscle was excised from the left carcass side, aged vacuum packaged for 10-13 days depending on the projects and frozen for less than eight months. TBARS and sensory analyses were performed on steaks displayed for 0, 4 or 9 days under simulated retail conditions, exposed to light in modified atmosphere packaging (CO(2):O(2); 25:75). Meat oxidation increased throughout display for each of the diets, as shown by a rise in TBARS values. This increase was not linear, differences between 0 and 4 days of display were smaller than between 4 and 9 days of display. The lowest TBARS and lowest increment occurred in the two control diets and the grass-fed animals, probably due to the more saturated fat of meat from animals fed the control diets and the higher content of vitamin E. Sensory attributes were also influenced by time of display. Positive attributes, such as beef flavour or overall liking, decreased throughout display, whereas negative attributes, such as abnormal and

  19. Heavy flavour decay properties with ATLAS

    Carli, Ina; The ATLAS collaboration

    2016-01-01

    We present the results on CP-violation searches in the Bs system, studied in the decay into J/psi phi, and the Bd system through the comparison of the decay time distributions in the flavour specific state J/psi K* and in the CP eigenstate J/psi KS. We additionally present new results in the search for the rare decays of Bs and Bd into mu+mu-. These searches are based on the full sample of data collected by ATLAS at 7 and 8 TeV collision energy. The consistency with the SM and with other available measurements is discussed.

  20. New Physics Search in Flavour Physics

    Hurth, Tobias

    2006-01-01

    With the running B, kaon and neutrino physics experiments, flavour physics takes centre stage within today's particle physics. We discuss the opportunities offered by these experiments in our search for new physics beyond the SM and discuss their complementarity to collider physics. We focus on rare B and kaon decays, highlighting specific observables in an exemplary mode. We also comment on the so-called B --> pi pi and B --> K pi puzzles. Moreover, we briefly discuss the restrictive role of long-distance strong interactions and some new tools such as QCD factorization and SCET to handle them.

  1. Heavy flavour production in 13 TeV pp collisions

    Braun, Svende Annelies

    2015-01-01

    This summer first data at the unprecedented energy of 13 TeV is collected at the LHC. This opens a new era in searches for new particles and precision tests of the Standard Model. Heavy flavour production plays an important role both as precision QCD test and as backgrounds for new particles. The first measurements of heavy flavour production are presented.

  2. Flavour democracy and the lepton-quark hierarchy

    The mass hierarchy of the leptons and quarks is interpreted as a consequence of a coherent state phenomenon ('flavour democracy'). It is emphasized that particular forms of the mass matrices can arise from the coherent state basis. The violations of the 'flavour democracy' turn out to be relatively large. Numerical examples are presented. (orig.)

  3. Exclusive search for supersymmetry with same-flavour di-lepton final states with the ATLAS detector

    Supersymmetry (SUSY) is one of the most promising extensions of the Standard Model of particle physics. It introduces a new symmetry between fermions and bosons by adding a bosonic superpartner to each SM fermion and a fermionic one to a each SM boson. If an excess of SUSY like signal is observed, SUSY particle properties (e.g. masses or mass differences) must be measured in order to determine the underlying SUSY parameters. Therefore, exclusive SUSY decay cascades with two leptons in the final state are isolated by the flavour subtraction method, in order to fit the endpoint of the invariant mass distribution of these leptons and determine SUSY particle mass differences. This analysis uses a data sample collected during the first half of 2011, corresponding to an integrated luminosity of 1 fb-1 of √(s)=7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Since no significant same flavour excess is observed, the variable S, which is the measure of a same-flavour excess, is used to determine model-independent and model-dependent limits for different SUSY scenarios. The tightest limits can be set for models expecting exactly two opposite-sign same-flavour leptons and missing transverse momentum larger than 250 GeV. Assuming no combinatorial SUSY background events from different decay chains (ll'), models with di-lepton decays (ll) with SUSY same-flavour excess Ss ≥4.5 can be excluded at 95% CL. Considering a combinatorial SUSY background contribution with a ratio BR(ll')/BR(ll)=50% (100%) models with Ss≥5.5(6.7) can be excluded at 95% CL. For the GMSB model with a slepton NLSP, this translates into a limit of the GMSB parameter Λ=40 TeV exceeding the current LEP limits.

  4. Exclusive search for supersymmetry with same-flavour di-lepton final states with the ATLAS detector

    Boehler, Michael

    2012-06-15

    Supersymmetry (SUSY) is one of the most promising extensions of the Standard Model of particle physics. It introduces a new symmetry between fermions and bosons by adding a bosonic superpartner to each SM fermion and a fermionic one to a each SM boson. If an excess of SUSY like signal is observed, SUSY particle properties (e.g. masses or mass differences) must be measured in order to determine the underlying SUSY parameters. Therefore, exclusive SUSY decay cascades with two leptons in the final state are isolated by the flavour subtraction method, in order to fit the endpoint of the invariant mass distribution of these leptons and determine SUSY particle mass differences. This analysis uses a data sample collected during the first half of 2011, corresponding to an integrated luminosity of 1 fb{sup -1} of {radical}(s)=7 TeV proton-proton collisions recorded with the ATLAS detector at the Large Hadron Collider. Since no significant same flavour excess is observed, the variable S, which is the measure of a same-flavour excess, is used to determine model-independent and model-dependent limits for different SUSY scenarios. The tightest limits can be set for models expecting exactly two opposite-sign same-flavour leptons and missing transverse momentum larger than 250 GeV. Assuming no combinatorial SUSY background events from different decay chains (ll'), models with di-lepton decays (ll) with SUSY same-flavour excess S{sub s} {>=}4.5 can be excluded at 95% CL. Considering a combinatorial SUSY background contribution with a ratio BR(ll')/BR(ll)=50% (100%) models with S{sub s}{>=}5.5(6.7) can be excluded at 95% CL. For the GMSB model with a slepton NLSP, this translates into a limit of the GMSB parameter {lambda}=40 TeV exceeding the current LEP limits.

  5. The supersymmetric flavour problem in 5D GUTs and its consequences for LHC phenomenology

    Brummer, Felix; Kraml, Sabine

    2011-01-01

    We study supersymmetric models with a GUT-sized extra dimension, where both the Higgs fields and the SUSY breaking hidden sector are localized on a 4D brane. Exponential wave function profiles of the matter fields give rise to hierarchical structures in the Yukawa couplings and soft terms. Such structures can naturally explain hierarchical fermion masses and mixings, while at the same time alleviating the supersymmetric flavour problem. We discuss two sources of supersymmetry breaking, radion mediation and brane fields, and perform a detailed numerical analysis, thoroughly taking into account the proliferation of unknown O(1) coefficients that occurs in this class of models. It turns out that additional assumptions on supersymmetry breaking are necessary to evade the stringent experimental bounds on lepton flavour violation. The favourable regions of parameter space are then examined with regards to their LHC phenomenology. They generically feature heavy gluinos and squarks beyond current bounds. Lepton flavo...

  6. On the Physics Case of a Super Flavour Factory

    Browder, T; Gershon, T; Hazumi, M; Hurth, Tobias; Okada, Y; Stocchi, A

    2008-01-01

    We summarize the physics case of a high-luminosity e+e- flavour factory collecting an integrated luminosity of 50-75 ab^(-1). Many New Physics sensitive measurements involving B and D mesons and tau leptons, unique to a Super Flavour Factory, can be performed with excellent sensitivity to new particles with masses up to ~100 (or even ~1000 TeV). Flavour- and CP-violating couplings of new particles that may be discovered at the LHC can be measured in most scenarios, even in unfavourable cases assuming minimal flavour violation. Together with the LHC, a Super Flavour Factory, following either the SuperKEKB or the SuperB proposal, could be soon starting the project of reconstructing the New Physics Lagrangian.

  7. Flavour constraints on multi-Higgs-doublet models: Yukawa alignment

    Pich, Antonio

    2010-01-01

    In multi-Higgs-doublet models, the alignment in flavour space of all Yukawa matrices coupling to a given right-handed fermion guarantees the absence of tree-level flavour-changing neutral couplings, while introducing new sources of CP violation. With N Higgs doublets (and no right-handed neutrinos) the Yukawa Lagrangian is characterized by the fermion masses, the CKM quark mixing matrix and 3(N-1) complex couplings. Quantum corrections break the alignment, generating a minimal-flavour-violation structure with flavour-blind phases. The aligned multi-Higgs-doublet models lead to a rich and viable phenomenology with an interesting hierarchy of flavour-changing neutral current effects, suppressing them in light-quark systems while allowing potentially relevant signals in heavy-quark transitions.

  8. Quark flavour observables in the Littlest Higgs model with T-parity after LHC Run 1

    Blanke, Monika; Buras, Andrzej J.; Recksiegel, Stefan

    2016-04-01

    The Littlest Higgs model with T-parity (LHT) belongs to the simplest new physics scenarios with new sources of flavour and CP violation. The latter originate in the interactions of ordinary quarks and leptons with heavy mirror quarks and leptons that are mediated by new heavy gauge bosons. Also a heavy fermionic top partner is present in this model which communicates with the SM fermions by means of standard W^± and Z^0 gauge bosons. We present a new analysis of quark flavour observables in the LHT model in view of the oncoming flavour precision era. We use all available information on the CKM parameters, lattice QCD input and experimental data on quark flavour observables and corresponding theoretical calculations, taking into account new lower bounds on the symmetry breaking scale and the mirror quark masses from the LHC. We investigate by how much the branching ratios for a number of rare K and B decays are still allowed to depart from their SM values. This includes K^+→ π ^+ν bar{ν }, KL→ π ^0ν bar{ν }, K_L→ μ ^+μ ^-, B→ X_sγ , B_{s,d}→ μ ^+μ ^-, B→ K^{(*)}ℓ ^+ℓ ^-, B→ K^{(*)}ν bar{ν }, and \\varepsilon '/\\varepsilon . Taking into account the constraints from Δ F=2 processes, significant departures from the SM predictions for K^+→ π ^+ν bar{ν } and KL→ π ^0ν bar{ν } are possible, while the effects in B decays are much smaller. In particular, the LHT model favours B(Bs→ μ ^+μ ^-) ≥ B(Bs→ μ ^+μ ^-)_SM, which is not supported by the data, and the present anomalies in B→ K^{(*)}ℓ ^+ℓ ^- decays cannot be explained in this model. With the recent lattice and large N input the imposition of the \\varepsilon '/\\varepsilon constraint implies a significant suppression of the branching ratio for KL→ π ^0ν bar{ν } with respect to its SM value while allowing only for small modifications of K^+→ π ^+ν bar{ν }. Finally, we investigate how the LHT physics could be distinguished from other models by means of

  9. Symmetry limit properties of a priori mixing amplitudes for non-leptonic and weak radiative decays of hyperons

    We show that, even if a priori mixings of positive-parity but flavour-violating eigenstates are allowed in physical hadrons, in the strong flavour symmetry limit the mixing angle will drop out of the matrix elements of the Yukawa and electromagnetic Hamiltonians that lead to non-leptonic and weak radiative decays of hyperons in this scheme. We compare this result with related theorems for the same W-mediated decays and give a concrete example of this behaviour by considering the U-spin symmetry of baryons and the U-doublet formed by p andΣ+. (author)

  10. Breaking Symmetries

    Peters, Kirstin

    2010-01-01

    A well-known result by Palamidessi tells us that {\\pi}mix (the {\\pi}-calculus with mixed choice) is more expressive than {\\pi}sep (its subset with only separate choice). The proof of this result argues with their different expressive power concerning leader election in symmetric networks. Later on, Gorla of- fered an arguably simpler proof that, instead of leader election in symmetric networks, employed the reducibility of "incestual" processes (mixed choices that include both enabled senders and receivers for the same channel) when running two copies in parallel. In both proofs, the role of breaking (ini- tial) symmetries is more or less apparent. In this paper, we shed more light on this role by re-proving the above result-based on a proper formalization of what it means to break symmetries-without referring to another layer of the distinguishing problem domain of leader election. Both Palamidessi and Gorla rephrased their results by stating that there is no uniform and reason- able encoding from {\\pi}mix i...

  11. Modelling the effect of oil/fat content in food systems on flavour absorption by LLDPE.

    Dekker, M.; Willige, van R.W.G.; Linssen, J.P.H.; Voragen, A.G.J.

    2003-01-01

    One of the phenomena in food packaging interactions is flavour absorption. Absorption of flavour compounds from food products into food-packaging materials can result in loss of flavour compounds or an unbalance in the flavour profile changing a product's quality. The food matrix influences the amou

  12. Flavour-changing neutral currents in the flavour-blind MSSM at large tanβ

    A popular way to avoid too large FCNC in supersymmetric models is the assumption of minimal flavour violation (MFV), where SUSY is broken by a flavour-blind mechanism. We study how loop effects which are enhanced at large tanβ can circumvent the MFV constraint to generate new FCNCs. We show that these effects can be resummed to all orders in perturbation theory in analogy to the tanβ-enhanced corrections to the bottom mass. This procedure yields new Feynman rules which automatically contain the enhanced effects without resorting to the decoupling limit. We also include the enhanced bottom-mass corrections and clarify their dependence on the input scheme. Finally, we study contributions to FCNC observables in B physics resulting from the new Feynman rules

  13. The Strong Interactions, Flavour Physics and Beyond

    Zuberi, Saba

    In this thesis we use effective field theories of the strong interactions to improve our understanding of several quantities in the Standard Model of particle physics (SM). We also examine constraints on an extension of the SM scalar sector and study the implications for the Higgs mass. We first examine an approach to extracting the Cabibbo-Kobayashi-Maskawa matrix element |Vub| via the relationship between the B meson decays B → X uℓnul and B → Xsgamma, where Xi is any final state hadron containing a quark of flavour i. Model dependence is reduced in this approach since the non-perturbative shape function at leading order is universal and drops out; however the perturbative expansion at next-to-leading order is found to be poorly behaved. We carry out a renormalon analysis of the relationship between these spectra to examine higher order perturbative corrections and compare the fixed-order and log expansions. Our analysis can be used to estimate the perturbative uncertainty in the extraction of |Vub|, which we show to be relatively small. Next we take a step towards the broader goal of summing large phase space logarithms from a variety of jet algorithms using Soft Collinear Effective Theory (SCET). We develop a consistent approach to implementing arbitrary phase space constraints in SCET and demonstrate the connection between cutoffs in SCET and phase space limits. By considering several jet algorithms at next-to-leading order, we gain some insight into factorization of final state jets. In particular, we point out the connection between the ultraviolet regulator and factorization. Finally we consider a scalar sector that contains a colour-octet electroweak-doublet scalar, in addition to the SM Higgs. This extension contains the only scalar representations that Yukawa-couple to quarks and are consistent with minimal flavour violation. We examine constraints from electroweak precision data, direct production from LEPII and the Tevatron, and from flavour

  14. Search for lepton flavour violation at HERA

    Hennekemper, E; Contreras, J G; Bruncko, D; Henderson, R C W; Martyn, H U; Rostovtsev, A; Olsson, J E; Feltesse, J; Buschhorn, G; Bozovic-Jelisavcic, I; Patel, G D; Pandurovic, M; Picuric, I; Staykova, Z; Povh, B; Campbell, A J; Backovic, S; Nowak, G; Ceccopieri, F; Fischer, D J; Kogler, R; Raicevic, N; Nowak, K; Polifka, R; Cvach, J; Huber, F; Lendermann, V; Mehta, A; Hildebrandt, M; Barrelet, E; Sauvan, E; Bizot, J C; Eisen, E; Sauter, M; Dobre, M; Schoeffel, L; Wunsch, E; Steder, M; Muller, K; Alexa, C; Henschel, H; Kleinwort, C; Papadopoulou, T; Pascaud, C; Pahl, P; Wegener, D; Boudry, V; Zacek, J; Turnau, J; Gogitidze, N; Robmann, R; Cerny, V; Niebuhr, C; Zomer, E; De Wolf, E A; Malinovski, E; Brinkmann, M; Fedotov, A; Schultz-Coulon, H C; Greenshaw, T; Horisberger, R; Mikocki, S; Chekelian, V; Gabathuler, E; Dodonov, V; Morris, J V; Valkarova, A; Glazov, A; Newman, P R; Salek, D; Sefkow, E; Lastovicka-Medin, G; Grab, C; Haidt, D; Grell, B R; Tseepeldorj, B; Toll, T; Van Mechelen, P; Goerlich, L; Bystritskaya, L; Ghazaryan, S; Specka, A; Spaskov, V; Laycock, R; Kluge, T; Fleischer, M; Rotaru, M; Vazdik, Y; von den Driesch, M V; Baghdasaryan, A; Pokorny, B; Panagoulias, I; Andreev, V; Zhang, Z; Felst, R; Lipka, K; Sankey, D P C; Baghdasaryan, S; Tsakov, I; Delcourt, B; Shushkevich, S; Kenyon, I R; Hreus, T; Lebedev, A; Aaron, F D; Habib, S; Coughlan, J A; Vallee, C; Shtarkov, L N; Herbst, M; Dubak, A; Schoning, A; Zhokin, A; Stella, B; Ferencei, J; Rusakov, S; Brisson, V; Osman, S; Favart, L; Dainton, J B; Belov, P; Schmitt, S; Sopicki, P; Soloviev, Y; Zohrabyan, H; Smiljanic, I; List, B; Perez, E; Tran, T H; Milcewicz-Mika, I; List, J; Bracinik, J; Dossanov, A; Traynor, D; Diaconu, C; Klein, M; Kraemer, M; Jung, H; Eckerlin, G; Pitzl, D; Petrukhin, A; Landon, M P J; Gayler, J; Jacquet, M; Delvax, J; Jonsson, L; Grindhammer, G; Bunyatyan, A; Helebrant, C; Hiller, K H; Sykora, T; Placakyte, R; Sloan, T; Cerny, K; Ravdandorj, T; Palichik, V; Fomenko, A; Kostka, P; Truol, P; Kapichine, M; Kretzschmar, J; Marage, P; Tabasco, J E R; Morozov, A; Brandt, G; Meyer, A B; Nikitin, D; Kruger, K; Naumann, T; Janssen, X; Daum, K; Stoicea, G; Zalesak, J; Britzger, D; Meyer, J; Meyer, H; Mudrinic, M; Straumann, U; Moreau, E; Bartel, W; Reimer, P; Kiesling, C; Avila, K B C; South, D; Eliseev, A; Roosen, R; Pirumov, H; Maxfield, S J; Grebenyuk, A; Belousov, A; Makankine, A; Ozerov, D; Hoffmann, D; Urban, K; Thompson, P D; Begzsuren, K; Lange, W; Egli, S; Gouzevitch, M; Levonian, S; Radescu, V; Piec, S; Lubimov, V

    2011-01-01

    A search for second and third generation scalar and vector leptoquarks produced in ep collisions via the lepton flavour violating processes ep -> mu X and ep -> tau X is performed by the H1 experiment at HERA. The full data sample taken at a centre-of-mass energy root s = 319 GeV is used for the analysis, corresponding to an integrated luminosity of 245 pb(-1) of e(+)p and 166 pb(-1) of e(-)p collision data. No evidence for the production of such leptoquarks is observed in the H1 data. Leptoquarks produced in e(+/-)p collisions with a coupling strength of lambda = 0.3 and decaying with the same coupling strength to a muon-quark pair or a tau-quark pair are excluded at 95\\% confidence level up to leptoquark masses of 712 GeV and 479 GeV, respectively.

  15. Flavour physics, supersymmetry and grand unification

    Nierste, Ulrich

    2011-01-01

    A global fit to quark flavour-physics data disfavours the Standard Model with 3.6 standard deviations and points towards new CP-violating physics in meson-antimeson mixing amplitudes. Tevatron data call for a new Bs-Bs-bar mixing phase and new physics in Bd-Bd-bar mixing alleviates the tension on the unitarity triangle driven by B(B-> tau nu). In supersymmetric GUT models the large atmospheric neutrino mixing angle can influence b -> s transitions. I present the results of a recent analysis in an SO(10) GUT model which accomodates the large Bs-Bs-bar mixing phase while simultaneously obeying all other experimental constraints.

  16. On the Isomorphic Description of Chiral Symmetry Breaking by Non-Unitary Lie Groups

    Bietenholz, Wolfgang

    2009-01-01

    It is well-known that chiral symmetry breaking ($\\chi$SB) in QCD with $N_{f}=2$ light quark flavours can be described by orthogonal groups as $O(4) \\to O(3)$, due to local isomorphisms. Here we discuss the question how specific this property is. We consider generalised forms of $\\chi$SB involving an arbitrary number of light flavours of continuum or lattice fermions, in various representations. We search systematically for isomorphic descriptions by non-unitary, compact Lie groups. It turns o...

  17. Fermion scattering in a gravitational background: electroweak corrections and flavour transitions

    We investigate the role of the electroweak corrections to the scattering cross section of Standard Model fermions with gravity. We use both an approach of scattering off an external potential, where the gravitational field is treated as a classical background generated by a heavy source, and the usual interaction based on the one-graviton-exchange. In the potential appoach we consider the fields both of a localized and of a distributed gravitational source of spherical symmetry and uniform density, separating the cases of interactions taking place both in the inner and external regions of the source. This allows to make a distinction between interactions involving neutrinos and dark matter particles with a realistic gravity source, which cover the inner region, and the rest of the Standard model fermions. The role of the gravitationally induced flavour-changing transitions, as well as the flavour diagonal ones, are investigated in the limit of both large and small momentum transfers, deriving the structure of the corresponding Hamiltonian

  18. The energy levels of the heavy flavour baryons in the topological soliton model

    The energy levels of the charm and bottom as well as the mixed flavour hyperons are calculated with the model in which the hyperons are described as bound states of a topological SU(2) soliton and K-, D- and B-mesons. The spectra are obtained in a modified version of the Skyrme model where the chiral symmetry breaking term in the Lagrangian density is modified so as to incorporate the different values of the decay constants of the mesons of different flavour. The predicted strange and charmed hyperon spectra are in very good agreement with the empirical values, while the bottom hyperon energies that are more sensitive to the short range dynamics are somewhat below the empirical values. The predicted hyperfine spectra are remarkably close to those obtained with the constituent quark model, more or less independently of the short-distance properties of the effective Lagrangian. We suggest that this feature reflects the presence of an induced nonabelian gauge potential generated by the interplay between 'fast' and 'slow' degrees of freedom in the meson-soliton system. (orig.)

  19. Risk assessment of flavouring substances used in foods

    Norby, Karin; Beltoft, Vibe Meister; Greve, Krestine;

    2006-01-01

    The aim of the present project, the FLAVIS project, is to perform risk assessment of chemically defined flavouring substances. The evaluations are then presented to the European Food Safety Authority (EFSA) for final adoption in its Scientific Panel on food additives, flavourings, processing aids...... EU. In application of this Regulation, a Register of about 2800 flavouring substances used in or on foodstuffs in the EU Member States was adopted and are currently being evaluated according to the evaluation programme laid down by Commission Regulation. The EU Safety Evaluation Procedure is derived...... not to present a safety concern, have been specified. In the project a very comprehensive database (the FLAVIS database) has been developed for the evaluation. It compiles information on the about 2800 flavouring substances used in Europe: specifications, structural class, food categories used in...

  20. Euroopa Liidu 7. Raamprogrammi projekt FLAVOURE / Marge Malbe

    Malbe, Marge, 1968-

    2011-01-01

    2009. a sai Eesti Maaviljeluse Instituut 843,270.00 € suuruse Euroopa Liidu finantseeringu 3 aastat kestva projekti FLAVOURE (Food and Feed Laboratory of Varied and Outstanding Research in Estonia) läbiviimiseks ja koordineerimiseks

  1. Two-point functions for flavour changing currents in QCD

    We complete the calculations of two-point functions in QCD by presenting the results for the flavour changing vector current, including perturbative and non-perturbative contributions (to first ordern in αsub(s)). (orig.)

  2. Open heavy flavour production: conceptual framework and implementation issues

    Heavy flavour production is an important quantum chromodynamics (QCD) process both in its own right and as a key component of precision global QCD analysis. Apparent disagreements between fixed-flavour scheme calculations of b-production rate with experimental measurements in hadro-, lepto- and photo-production provide new impetus for a thorough examination of the theory and phenomenology of this process. We review existing methods of calculation and place them in the context of the general perturbative QCD framework of Collins. A distinction is drawn between scheme dependence and implementation issues related to quark mass effects near threshold. We point out a so far overlooked kinematic constraint on the threshold behaviour, which greatly simplifies the variable flavour number scheme. This obviates the need for the elaborate existing prescriptions and leads to robust predictions. It can facilitate the study of current issues on heavy flavour production as well as precision global QCD analysis. (author)

  3. Flavour-changing neutral currents in models with extra ' boson

    S Sahoo; L Maharana

    2004-09-01

    New neutral gauge bosons ' are the features of many models addressing the physics beyond the standard model. Together with the existence of new neutral gauge bosons, models based on extended gauge groups (rank > 4) often predict new charged fermions also. A mixing of the known fermions with new states, with exotic weak-isospin assignments (left-handed singlets and right-handed doublets) will induce tree-level flavour-changing neutral interactions mediated by exchange, while if the mixing is only with new states with ordinary weak-isospin assignments, the flavour-changing neutral currents are mainly due to the exchange of the new neutral gauge boson '. We review flavour-changing neutral currents in models with extra ' boson. Then we discuss some flavour-changing processes forbidden in the standard model and new contributions to standard model processes.

  4. Risk assessment of flavouring substances used in foods

    Norby, Karin; Beltoft, Vibe Meister; Greve, Krestine; Reffstrup, Trine Klein; Gry, Jørn

    2006-01-01

    not to present a safety concern, have been specified. In the project a very comprehensive database (the FLAVIS database) has been developed for the evaluation. It compiles information on the about 2800 flavouring substances used in Europe: specifications, structural class, food categories used in......The aim of the present project, the FLAVIS project, is to perform risk assessment of chemically defined flavouring substances. The evaluations are then presented to the European Food Safety Authority (EFSA) for final adoption in its Scientific Panel on food additives, flavourings, processing aids...... and materials in contact with food. The regulatory background for the work is found in the European Parliament and Council Regulation No. 2232/96 laying down a procedure for the establishment of a list of flavouring substances the use of which will be authorised to the exclusion of all others in the...

  5. CP and other Symmetries of Symmetries

    Trautner, Andreas

    2016-01-01

    Outer automorphisms of symmetries ("symmetries of symmetries") in relativistic quantum field theories are studied, including charge conjugation (C), space-reflection (P) , and time-reversal (T) transformations. The group theory of outer automorphisms is pedagogically introduced and it is shown that CP transformations are special outer automorphisms of the global, local, and space-time symmetries of a theory. It is shown that certain discrete groups allow for a group theoretical prediction of parameter independent CP violating complex phases with fixed geometrical values. The remainder of this thesis pioneers the study of outer automorphisms which are not related to C, P, or T. It is shown how outer automorphisms, in general, relate symmetry invariants and, in theories with spontaneous symmetry breaking, imply relations between different vacuum expectation values. Thereby, outer automorphisms can give rise to emergent symmetries. An example model with a discrete symmetry and three copies of the Standard Model ...

  6. The negative binomial distribution in quark jets with fixed flavour

    Alberto GiovanniniTurin U. & INFN, Turin; Sergio Lupia(Munich, Max Planck Inst.); Roberto Ugoccioni(Lund U.)

    2015-01-01

    We show that both the multiplicity distribution and the ratio of factorial cumulants over factorial moments for 2-jet events in e+e- annihilation at the Z^0 peak can be well reproduced by the weighted superposition of two negative binomial distributions, associated to the contribution of $b\\bar b$ and light flavoured events respectively. The negative binomial distribution is then suggested to describe the multiplicity distribution of 2-jet events with fixed flavour.

  7. Formation of Amino Acid Derived Cheese Flavour Compounds

    Smit, B.A.

    2004-01-01

    Lactic acid bacteria (LAB), among them Lactococcus lactis, are often used for the fermentation of milk into various products, such as cheeses. For their growth and maintenance LAB metabolise milk sugar, protein and fat into various low molecular compounds, which sometimes have strong flavour characteristics. This thesis focuses on the production of one class of these compounds as a model system: aldehydes, in particular the key-flavour compounds 3-methylbutanal and 2-methyl propanal, which ar...

  8. Theory of electric dipole moments and lepton flavour violation

    Jung, Martin

    2016-01-01

    Electric dipole moments and charged-lepton flavour-violating processes are extremely sensitive probes for new physics, complementary to direct searches as well as flavour-changing processes in the quark sector. Beyond the "smoking-gun" feature of a potential significant measurement, however, it is crucial to understand their implications for new physics models quantitatively. The corresponding multi-scale problem of relating the existing high-precision measurements to fundamental parameters c...

  9. Relationship between texture of gels and flavour release

    Koliandris, Andreas

    2009-01-01

    To provide further insight into the relationship between the structure of hydrocolloid solutions and gels and perception of taste and flavour, solutions of gelatin and locust bean gum, and gels prepared from mixtures of (a) high acyl and low acyl gellan (b) carrageenan and locust bean gum were studied. Both solutions contained sodium chloride and the gels were flavoured with ethyl butyrate. The gels were classified from rheological measurements into 3 categories: strong/brittle, intermedi...

  10. Impact on odorant partition coefficients and flavour perception

    Rusu, Manuela

    2007-01-01

    Foods are complex multi-component systems which are composed of volatile and non-volatile substances. The flavour profile of a food is an important criterion for the selection of our foodstuffs. The main objective of this study was the clarification of the complex relationships of the flavour release as a function of the composition of the food matrix at molecular level. Therefore the influence of matrix effects onto the partition coefficients, odour activity values and sens...