Search

We study the flavor-changing couplings of the Higgs-boson with the top-quark using the processes: (a) pp --> tt, (b) pp --> t_bar j, and, (c) pp --> t_bar j h at the LHC in light of current discovery of a 126 GeV Higgs-Boson. Sensitivities for the flavor-changing couplings are estimated using the LHC data that was collected until spring 2013. It is found that the process (c) is the most capable of yielding the best upper bound on the flavor-changing couplings with 2 sigma level sensitivities of {|xi_{tc}^2 + xi_{tu}^2|}^{1/2} <= 4.2 x 10^{-3} and <= 1.7 x 10^{-3} resulting from t --> b l nu_l, h --> jj with the 7 TeV and 8 TeV centre-of-mass energies respectively using existing data from the LHC. The corresponding bounds from h --> b b_bar are worse by a factor of about 1.8., Comment: 19 Latex Pages, 2 Figures, 6 Tables, More SM backgrounds, corrected some typos and errors, added h->2j detection mode, further improvements and a new subsection on 14 TeV was added. More refs. were incorporated

We study the connection between the same sign top (SST) and the top quark forward-backward asymmetry $A^t_{FB}$. We find that a large class of new physics models that have been proposed to account for the $A^t_{FB}$ lead to SST quark production rate much larger than the observed rate at the LHC and consequently are severely constrained or ruled out. Our model independent, general, operator analysis shows that none of the tree-level flavor-changing operators are able to explain $A^t_{FB}$ and simultaneously remain consistent with the same-sign top-quark production constraints from the LHC data., Comment: 19 LaTeX pages, 3 Tables and 4 png Figures, accepted version for publication in JHEP

The recent evidence of large direct CP violation in D0 decay at LHCb suggests that such CP studies may become an important avenue for understanding CP. In this paper, we make several suggestions to try to clarify the role of new physics in these results. We propose that the enhancement needed in the Standard Model to attribute the observed CP violation in D to two pseudoscalar modes may not operate for inclusive final states where asymmetries will likely approximate the quark level expectation. Experimentally testing this principle requires a search for CP asymmetries in final states containing K and K-bar with a total energy of less than M_D. We also propose that CP asymmetries may be enhanced in modes where the tree is color suppressed. In particular, the final state rho0 rho0 is of special interest; similarly Ds-> rho0 K+ and rho0 K*+ likewise appear interesting. We discuss how isospin symmetry yields observables sensitive to certain classes of new physics and suppressed in the Standard Model. Some modes considered in this context are D-> pi pi, rho pi, rho rho as well as Ds-> K* pi. We also consider how such analysis may eventually be supplemented by information about the weak phases in D0 decay. In order to obtain this information experimentally, we consider various methods for preparing an initial state which is a quantum mechanical mixture of D0 and D0-bar. This may be done through the use of natural D0 D0-bar oscillations; observing D0-mesons which arise from Bd or Bs mesons which themselves are oscillating or from quantum correlations in D0 pairs which arise from either psi" decay or B-meson decay. Observing CP violation in the magnitudes of decay amplitudes should be within the capability of experiments in the near future however obtaining the weak phases through the methods we discuss will likely require future generations of machines., Comment: 21 pages, 4 figures, 1 table; Version to appear in journal

We consider the phenomenology of the fourth generation heavy quarks which would be pair produced at the LHC. We show that if such a quark with a mass in the phenomenologically interesting range of 400 GeV--600 GeV decays to a light quark and a W-boson, it will produce a signal in a number of channels which can be seen above the background from the three generation Standard Model processes. In particular, such quarks could be seen in channels where multiple jets are present with large missing momentum and either a single hard lepton, an opposite sign hard lepton pair or a same sign lepton pair. In the same sign dilepton channel there is little background and so an excess of such pairs at large invariant mass will indicate the presence of heavy down type quarks. More generally, in our study, the main tool we use to determine the mass of the heavy quark in each of the channels we consider is to use the kinematics of the decay of such quarks to resolve the momenta of the unobserved neutrinos. We show how this can be carried out, even in cases where the kinematics is under-determined by use of the approximation, which holds quite well, that the two heavy quarks are nearly at rest in the center of mass frame. Since it is very likely that at least the lightest heavy quark decays in the mode we consider, this means that it should be observed at the LHC. Indeed, it is expected that the mass splitting between the quarks is less than $m_W$ so that if the Cabbibo-Kobayshi-Maskawa (CKM) matrix element between the fourth and lower generations are not too small, both members of the fourth generation quark doublet will decay in this way. If this is so, the combined signal of these two quarks will make the signal for the fourth generation somewhat more prominent., Comment: 26 pages; 15 Figures; In version 2 we have added some references and corrected some typos; Version 3 we have made minor change to some figure captions

We investigate triphoton signals of the Randall-Sundram model at the Large Hadron Collider. Such a signal can be an important probe to the RS model as these are relatively cleaner from the hadronic activity and bear significant rate. The corresponding standard model background has also been studied in detail. We also show that a clear graviton reconstruction is possible in such signal., Comment: 11 LaTeX Pages, 8 EPS Figures

About 90% of Bs-bar Bs pairs produced at the Upsilon(5s) resonance are initially Bs*-bar Bs* pairs which decay radiatively to Bs-bar Bs. This implies that the Bs pair will then be in an eigenstate of charge conjugation (i.e. C=-1) and therefore in an entangled state. This allows for a determination of Delta Gamma/Gamma and the CP phase using a number of possible correlations between the decays of the two Bs mesons. In particular, we consider the time integrated correlation; the time ordering asymmetry and the time ordering-charge asymmetry, which in addition to time ordering distinguishes Bs from Bs-bar, for various combinations of final states. With the statistics of about O(10^7-10^8) Upsilon(5s) events available at B factories, we find that the time ordering asymmetry between suitably defined hadronic and flavor specific (tagging) decays offers a promising method for determining the width difference. The corresponding time ordering-charge asymmetry can also bound the mixing phase. Similar observables involving exclusive decays are also considered. At the super B factories with O(50) times greater luminosity time ordering and time ordering-charge asymmetries between inclusive and exclusive modes may also provide additional bounds on the phases in those decays, Comment: no figures; Updated version: This is the version accepted by Phys Rev D; Some additional comments were added between equations 8 and 12, also reference 20 to recent D0 results was added

The original Randall-Sundrum (RS) model with a warped extra dimension along with extensions provides the possibility for a simultaneous solution to Planck-weak hierarchy problem as well as the flavor puzzle in the Standard Model (SM). The most distinctive feature of this scenario is the existence of Kaluza-Klein (KK) gravitons whose masses and couplings to the SM fields are set by the TeV scale. In some realistic versions of this framework, the largest coupling of the gravitons to the observed particles is to the top quark and unphysical Higgses ($W^{\pm}_L$ and $Z_L$) with the KK graviton (G) masses predicted to be $\gsim$ 4 TeV. We extend earlier works on the KK graviton decays to the $t\bar{t}$ final state and to the ``gold-plated'' $Z_L Z_L$ modes (with each Z decaying to $e^+ e^-$ or to $\mu^+ \mu^-$) by studying the resonant production of the gravitons and their subsequent decay to $W_L W_L$ pair. We find that with 300 $fb^{-1}$ integrated luminosity of data the semileptonic $G \to W (\to l \nu_l) W(\to 2 jets)$ mode offers a good opportunity to search for the RS KK graviton mode with mass lighter than $\sim$ 3-3.5 TeV at the CERN LHC. Efficient WW mass reconstruction in the semileptonic mode combined with an analysis of dilepton mass distribution in the purely leptonic channel, $pp \to W (\to l \nu_l) W(\to l^\prime \nu_{l^\prime})$ may help to observe KK $Z^\prime$ and KK graviton separately. Suitably defined average energy of the charged lepton in the semileptonic mode may be used to distinguish decays from longitudinal versus transverse W-bosons., Comment: 19 pages, 6 figures, 4 tables; Accepted for publication in Phys. Lett. B

In radiative B decays to final states containing one spin zero meson, one spin one meson and a photon, the photon polarization can be measured from the angular distribution of the final state. The P-odd, C-even components of this distribution lead to triple correlation asymmetries that are very sensitive to new physics as they are likely to receive only tiny contributions from the Standard Model. There are also (CP-conserving) forward-backward asymmetries to which there may be SM contributions of a few percent; nevertheless there is a data driven means to overcome the SM ``pollution''. These latter observables can be used to search for a class of New Physics which does not necessarily possess a new CP-odd phase, and wherein the current structure is different from the left-handed electroweak theory of the Standard Model. The mode $B^\pm \to K^\pm \phi \gamma$ is particularly useful due to the relatively large branching ratio and its distinctive final state but there are dozens of such final states in the decays of $B_u$, $B_d$ and $B_s$ mesons where the analysis is applicable. In many cases, after the decay of the spin one resonance, several of these channels lead to only charged mesons and a photon in the final state, so they may well be accessible in a hadronic environment in addition, of course, to $e^+ e^-$ (Super) $B$ Factories. In passing we also briefly explain why the CP-conserving forward-backward asymmetries in $B \to P V \gamma$ decays is a more reliable signal of new physics compared to the (CP-conserving) transverse polarization in $B \to V_1 V_2$ modes even though, of course, the latter may be somewhat more abundant., Comment: latex, 16 pages

A charged Higgs pair can be produced at an ee collider through a t-channel exchange of a heavy neutrino (N) via e^+ e^- -> H^+ H^- and, if N is a Majorana particle, also via the lepton number violating (LNV) like-sign reaction e^\pm e^\pm \to H^\pm H^\pm. Assuming no a-priori relation between the effective eNH^+ coupling (\xi) and light neutrino masses, we show that this interaction vertex can give a striking enhancement to these charged Higgs pair production processes. In particular, the LNV H^-H^- signal can probe N at the ILC in the mass range 100 GeV < m_N < 10^4 TeV and with the effective mixing angle, \xi, in the range 10^{-4} < \xi^2 < 10^{-8} - well within its perturbative unitarity bound and the neutrinoless double beta decay (\beta\beta_{0\nu}) limit. The lepton number conserving (LNC) e^+ e^- \to H^+ H^- mode can be sensitive to, e.g., an O(10) TeV heavy Majorana neutrino at a 500 GeV International Linear Collider (ILC), if \xi^2 > 0.001., Comment: Latex, 5 pages, 3 figures. V2 as published in PRD

We examine neutrino oscillations in a two Higgs doublet model (2HDM) in which the second doublet couples only to the third generation right-handed up-fermions, i.e., to t_R and to N_3 which is the heaviest right-handed Majorana neutrino. The inherently large tan(beta) of this model can naturally account for the large top mass and, based on a quark-lepton similarity ansatz, when embedded into a seesaw mechanism it can also account for the observed neutrino masses and mixing angles giving a very small theta_13: -0.017 < theta_13 < 0.021 at 99% CL, and a very restrictive prediction for the atmospheric mixing angle: 42.9(deg) < theta_atm < 45.2(deg) at 99% CL. The large value of tan(beta) also sets the mass scale of the heaviest right-handed Majorana neutrino N_3 and triggers successful leptogenesis through a CP-asymmetry in the decays of the N_1 (lightest right-handed Majorana) which is tan^2(beta) enhanced compared to the CP-asymmetry obtained in models for leptogenesis with one Higgs doublet or in the MSSM. This enhancement allows us to relax the lower bound on M_{N_1} and consequently also the lower bound on the reheating temperature of the early universe., Comment: 4 pages, talk given at the International Europhysics Conference on High Energy Physics, July 21st - 27th 2005, Lisboa, Portugal and at the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, June 12th-17th 2006, Irvine, California, USA

We describe a model for the scalar sector where all interactions occur either at an ultra-high scale L_U ~ 10^16 - 10^19 GeV or at an intermediate scale L_I=10^9 - 10^11 GeV. The interaction of physics on these two scales results in an SU(2) Higgs condensate at the electroweak (EW) scale, L_EW, through a seesaw-like Higgs mechanism, L_EW ~ (L_I)^2/L_U, while the breaking of the SM SU(2)XU(1) gauge symmetry occurs at the intermediate scale L_I. The EW scale is, therefore, not fundamental but is naturally generated in terms of ultra-high energy phenomena and so the hierarchy problem is alleviated. We show that our ``seesaw-Higgs'' model predicts the existence of sub-eV neutrino masses which are generated through a ``two-step'' seesaw mechanism in terms of the same two ultra-high scales: m_nu ~ (L_I)^4/(L_U)^3 ~ (L_EW)^2/L_U. We also show that our seesaw Higgs model can be naturally embedded in theories with tiny extra dimensions of size R ~ 1/L_U ~ 10^{-16} fm, where the seesaw induced EW scale arises from a violation of a symmetry at a distant brane if there are 7 tiny extra dimensions., Comment: 3 pages, talk given at the International Europhysics Conference on High Energy Physics, July 21st - 27th 2005, Lisboa, Portugal

We examine neutrino oscillations in a two Higgs doublet model (2HDM) in which the second doublet couples only to the third generation right-handed up-fermions, i.e., to t_R and to N_3 which is the heaviest right-handed Majorana neutrino. The inherently large tan(beta) of this model can naturally account for the large top mass and, based on a quark-lepton similarity ansatz, when embedded into a seesaw mechanism it can also account for the observed neutrino masses and mixing angles giving a very small \theta_{13}: -0.017 < \theta_{13} < 0.021 at 99% CL, and a very restrictive prediction for the atmospheric mixing angle: 42.9^0 < \theta_{atm} < 45.2^0 at 99% CL. The large value of tan(beta) also sets the mass scale of the heaviest right-handed Majorana neutrino N_3 and triggers successful leptogenesis through a CP-asymmetry in the decays of the N_1 (lightest right-handed Majorana) which is tan^2(beta) enhanced compared to the CP-asymmetry obtained in models for leptogenesis with one Higgs doublet or in the MSSM. This enhancement allows us to relax the lower bound on M_{N_1} and consequently also the lower bound on the reheating temperature of the early universe., Comment: 2 pages, 2 figures. Important changes made in v2: 1) improved presentation of leptogenesis and 2) a more elaborate discussion on the assumed texture zeros in the neutrino Yukawa sector. Important changes made in v3: minor changes added to emphasize that in our model the CP-asymmetry in the decays of the lightest Majorana is enhanced by tan^2(beta)~O(100) compared to models with one Higgs doublet as well as with respect to the MSSM

We show that in a decay of the form B_d or B_s-> P_1 P_2 gamma (where P_1 and P_2 are pseudoscalar mesons), through a flavor changing dipole transition, time dependent oscillations can reveal the presence of physics beyond the Standard Model. If P_1 and P_2 are CP eigenstates (e.g. as in B_d -> K_S pi0 gamma), the oscillation is independent of the resonance structure. Thus data from resonances as well as from nonresonant decays can be included. This may significantly enhance the sensitivity to new physics of the method. If P_1 is a charged particle, and P_2 its anti-particle (e.g. as in B_d -> pi+ pi- gamma), one has the additional advantage that both the magnitude and the weak phase of any new physics contribution can be determined from a study of the angular distribution. These signals offer excellent ways to detect new physics because they are suppressed in the Standard Model. We also show that the potential contamination of these signals originating from the Standard Model annihilation diagram gives rise to photons with, to a very good approximation, the same helicity as the dominant penguin graph and thus causes no serious difficulty., Comment: 13 pages 4 figures Version 4: We have added a para (2nd para below Eqn.39, Section VII) and a new Ref. (#20)

We describe a model for the scalar sector where all interactions occur either at an ultra-high scale L_U ~ 10^{16}-10^{19} GeV or at an intermediate scale L_I ~ 10^{9}-10^{11} GeV. The interaction of physics on these two scales results in an SU(2) Higgs condensate at the electroweak (EW) scale, L_{EW}, through a seesaw-like Higgs mechanism, L_{EW} ~ L_I^2/L_U, while the breaking of the SM SU(2)XU(1) gauge symmetry occurs at the intermediate scale L_I. The EW scale is, therefore, not fundamental but is naturally generated in terms of ultra-high energy phenomena and so the hierarchy problem is alleviated. We show that the class of such ``seesaw Higgs'' models predict the existence of sub-eV neutrino masses which are generated through a ``two-step'' seesaw mechanism in terms of the same two ultra-high scales: m_nu ~ L_I^4/L_U^3 ~ L_{EW}^2/L_U. The neutrinos can be either Dirac or Majorana, depending on the structure of the scalar potential. We also show that our seesaw Higgs model can be naturally embedded in theories with tiny extra dimensions of size R ~ 1/L_U ~ 10^{-16} fm, where the seesaw induced EW scale arises from a violation of a symmetry at a distant brane; in particular, in the scenario presented there are 7 tiny extra dimensions., Comment: latex, 25 pages, no figures. Version 2 is a shorter version (as accepted in EPJC), not including the discussion on the heavy seesaw Higgs model

The implementation of various methods for the determination of gamma through direct CP violation arising in the interference of b->c and b->u processes in charged as well as neutral B meson decays are considered. We show that the inclusion of D0 resulting from D*0-->D0+pi0(gamma) say via B-->KD*0 makes a significant difference in the attainable accuracy for gamma. Both exclusive and inclusive decays of the B+- and B0 to states containing D0/D0-bar followed by both inclusive and exclusive decays of the D0 are discussed. It is shown that with statistics which might be obtained at B factories (5-10 X 10^8 B-pairs) a 1-sigma determination of gamma to about +-5 degrees may be possible depending on the efficiency of reconstruction, backgrounds and the details of the decay amplitudes involved. The role of data from a charm factory as well as effects of D0 mixing are discussed. Extraction of gamma with accuracy that is roughly commensurate with the intrinsic theory error of these methods (i.e. around 0.1%), which is an important goal, will require >10^{10} B-pairs, namely a Super-B Factory., Comment: 20 Pages, 10 Figures, a new figure and references added

Assuming that a non-standard neutral Higgs with an enhanced Yukawa coupling to a bottom quark is observed at future hadron experiments, we propose a method for a better understanding of the Higgs sector. Our procedure is based on "counting" the number of events with heavy jets (where "heavy" stands for a c or b jet) versus b jets, in the final state of processes in which the Higgs is produced in association with a single high p_T c or b jet. We show that an observed signal of the type proposed, at either the Tevatron or the LHC, will rule out the popular two Higgs doublet model of type II as well as its supersymmetric version - the Minimal Supersymmetric Standard Model (MSSM), and may provide new evidence in favor of some more exotic multi Higgs scenarios. As an example, we show that in a version of a two Higgs doublet model which naturally accounts for the large mass of the top quark, our signal can be easily detected at the LHC within that framework. We also find that such a signal may be observable at the upgraded Tevatron RunIII, if the neutral Higgs in this model has a mass around 100 GeV and \tan\beta > 50 and if the efficiency for distinguishing a c jet from a light jet will reach the level of 50%., Comment: Revtex, 11 pages, 4 figures embedded in the text. Main changes with respect to Version 1: Numerical results re-calculated using the CTEQ5L pdf, improved discussion on the experimental consequences, new references added. Conclusions remain unchanged. As will appear in Phys. Rev. D

We investigate a class of models for new physics which could produce a large difference in sin 2 beta between B0-> J/\psi K(S) and the ``pure penguin'' mode B0-> phi K(S). In such models, the dominant effect is through a Z-penguin and therefore a pattern of deviation in sin 2beta as measured in B0-> chi(1) K(S); eta(c) K(S); J/\psi K(S) and psi-prime K(S) is predicted. If the preliminary data concerning the discrepancy between J/\psi K(S) and phi K(S) proves correct in magnitude, discrepancies in these other modes would likely be observable. We also consider the effects such new physics could have on the B(s) system and the isospin analysis of B-> K\pi. We compare this scenario with a scenario where contributions to sin 2beta in various modes is produced by gluino loops and down squark mixing., Comment: 19 Pages, 6 figures; references added

We discuss the determination of the CKM phase gamma through the decay B- -> K- D0 and related processes. In particular, we consider the use of this methods when the D0 subsequently decays to an inclusive state. We emphasize that strong phase information obtained at a psi(3770) charm factory can provide additional information which will be helpful in determining gamma., Comment: Invited talk at the Workshop on the CKM Unitarity Triangle, IPPP Durham, April 2003 (eConf C0304052). 4 pages LaTeX, 4 eps figures

We study the inclusive semileptonic rare decay $b \to s l^+ l^-$ in minimal supergravity model (mSUGRA). If tan$\beta$ is large, down-type quark mass matrices and their Yukawa couplings cannot be diagonalized at the same basis. This induces the flavor violating neutral Higgs boson couplings. These couplings contribute significantly to decay $b \to s mu^+ mu^-$ and $b \to s tau^+ tau^-$, but negligible to $b \to s e^+ e^-$ decay because of its negligible $m_e$ mass. The ratio $R \equiv B(b \to s mu^+ mu^-)/ B(b \to s e^+ e^-)$ can be very different from its corresponding value in the Standard Model. We find that part of parameter space can accommodate a large R value, and that maximum R value can be larger than 2. We also present our results in $b \to s tau^+ tau^-$ decay channel. Although it can be not detected now, it is potentially a new channel for the future observation of new physics., Comment: 9 pages and 4 figures

In this paper we study the impact of data that can be obtained from a Charm Factory on the determination of the CKM parameter gamma from decays of the form B -> D0 K where the D0 decays to specific inclusive and exclusive final states. In particular, for each exclusive final state $f$, the charm factory can determine the strong phase difference between D0-> f and D0-bar -> f by exploiting correlations in psi(3770)-> D0 D0-bar. This provides crucial input to the determination of gamma via the interference of B+- -> K+- D0 -> f with B+- -> K+- D0-bar -> f. We discuss how the method may be generalized to inclusive final states and illustrate with a toy model how such methods may offer one of the best means to determine gamma with 10^8-10^9 B-mesons., Comment: 12 pages, 7 figures, Version 2: Fixed typos; add reference; Version 3: fixed latex glitch

There is no good reason to think that BSM-CP-odd phases(s) will necessarily cause large deviations in B-physics from predictions of the SM. Therefore, residual theory error in extraction of the unitarity triangle can undermine experimental efforts to search for BSM phase(s). We stress that final states containing D0 or D0-bar in decays of charged and neutral B's can yield all the angles of the unitarity triangle with negligble theory error (i.e. O(0.1%))., Comment: Invited talk given at XIVth Rencontres de Blois, Matter-Antimatter Asymmetry, Chateau de Blois (France), 16-22 June 2002

Heavy meson pairs produced in the decays of heavy quarkonium resonances at e+ e- machines (beauty and tau-charm factories) have the useful property that the two mesons are in the CP-correlated states. By tagging one of the mesons as a CP eigenstate, a lifetime difference of heavy neutral meson mass eigenstates width difference may be determined by measuring the leptonic branching ratio of the other meson. We discuss the use of this and related methods both in the case where time dependent mixing is small and when it is significant. We consider the impact of possible CP-violating effects and present the complete results for CP-entangled decay rates with CP-violation taken into account., Comment: 14 pages, 0 figures; 2 references added, results unchanged

Oscillation effects in B0 -> Ks D0 and related processes are considered to determine delta=beta-alpha+pi. We suggest that D0 decays to CP eigenstates used in concert with inclusive D0 decays provide a powerful method for determining delta cleanly i.e. without any complication from penguin processes. The CP asymmetry is expected to be <=40% for D0 decays to non-CP eigenstates and <=80% for decays to CP eigenstates. This method can lead to a fairly accurate determination of delta with O(10^8-10^9) B-mesons., Comment: 4 pages 1 figure; Version 2: minor changes; references added; Some changes in response to Referee Comments

The flavor changing decay Z -> d_I \bar{d}_J is investigated with special emphasis on the b \bar{s} final state. Various models for flavor violation are considered: two Higgs doublet models (2HDM's), supersymmetry (SUSY) with flavor violation in the up and down-type squark mass matrices and SUSY with flavor violation mediated by R-parity-violating interaction. We find that, within the SUSY scenarios for flavor violation, the branching ratio for the decay Z -> b \bar{s} can reach 10^{-6} for large \tan\beta values, while the typical size for this branching ratio in the 2HDM's considered is about two orders of magnitudes smaller at best. Thus, flavor changing SUSY signatures in radiative Z decays such as Z -> b \bar{s} may be accessible to future ``Z factories'' such as a Giga-Z version of the TESLA design., Comment: 27 pages, 15 figures, REVTeX4. A new section added and a few minor corrections were made in the text

We consider the possibility of studying the CP properties of various B(s) decays at an electro-positron machine tuned to the Upsilon(5s). Since decay modes of the B(s) with definite CP are relatively rare, we suggest that the use of more common modes which are not pure CP eigenstates may allow the determination of the CKM phase gamma. By studying the degree of correlation between different decay modes at a Upsilon(5s) it is possible to determine the degree of affinity of each decay mode to a CP eigenstate. Once this is known, the correlation between a decay mode with a greater affinity to a particular CP eigenstate with a mode such as D(s) + K- gives a determination of the phase gamma., Comment: 12 pages; In version 2, we have corrected some typos and equation 13 as well as adding some references

A method is proposed for the determination of the unitarity angle alpha through tree penguin interference. The modes needed would be of the form B0/B0-bar -> rho0 M and B0/B0-bar -> omega M where M is spin-0 uu-bar/dd-bar meson, for instance M=pi0, eta, eta',a0 or f0. An analogous method can also determine gamma using M=KS or K_L. The validity of the theoretical approximations used may be tested by over determining alpha with several modes. If two or more modes are used, the determination has a four-fold ambiguity but additional information from pure penguin decays or theoretical estimates may be used to reduce the ambiguity to alpha, alpha+pi. The method as applied to determining gamma is probably less promising., Comment: 17 pages, 2 figures; Small change with respect to the references and a postscript bug in the figures fixed

A method for clean determination of the unitarity angles alpha and gamma is proposed that uses only direct CP violation and does not require any time dependent measurements. The method takes advantage of helicity amplitudes for B_u, B_d and B_s decay to two vector mesons and can be used, at any B-facility, in conjunction with a large number of modes. It also allows for experimental tests of theoretical approximations involved., Comment: 12 pages, no figures

Direct CP violation in decays such as B- -> D0 K- is sensitive to the CKM angle phi_3 because these decays allow the interference of b-quark to c-quark with b-quark to u-quark transitions. Indeed, phi_3 may be determined if one can infer the strong phase of the B and subsequent D0 decays from experimental data. In this talk, I will discuss how this can be carried out using either a single decay mode of the D0 by combining data from a number of D0 decay modes as well as the use of other, analogous decays and the prospects of implementing such methods at various B-factories. Since the properties of the D0 decays are crucial to these methods, it is possible that D0-D0-bar mixing at the 1% level will contaminate the results. I will therefore discuss various methods to remove such confounding effects so that phi-3 may be determined even if such mixing is present., Comment: BCP4 Conference Proceedings: 5 pages; 3 figures

Recent experimental observations of CP asymmetry in B0 -> psi K0 constitute the first significant signal of CP violation outside the neutral kaon system; thus they represent an important milestone to test the CKM paradigm. We, therefore, undertake a critical appraisal of the existing experimental and theoretical inputs used to deduce constraints on sin(2 beta) and other important parameters and thus find, in particular, sin(2 beta) > 0.50 at 95% CL which is completely compatible with the combined experimental result: sin(2 beta) = 0.46 +- 0.17, representing an important success of the CKM model of CP violation. Searches for new physics in B decays to psi+K0 like final states will require improved precision; we make some suggestions to facilitate these. We also present a global fit including the new CP asymmetry measurements in B->psi+K0 as an additional input yielding e.g. gamma =29-56 degrees, eta-bar = >.19-.36, rho-bar=.15-.37, Jcp=(1.8 - 3.0) X 10^(-5), $Br(K+ -> pi+ nu nu-bar)=(0.51 - 0.90) X 10^(-10) and Br(KL -> pi0 nu nu-bar) = (0.11 - 0.31) X 10^(-10) at 95% CL., Comment: 20 pages, 5 figures: In this version, which is to appear in Phys. Lett. B, we have: 1) corrected a minor error in the fitting algorithm which lowers the lower bound on rho-bar somewhat, 2) deleted figure 4(b) to save space and in figures 1(a), 4 and 5 we have included the 2-sigma (theory) error on x_i in displaying the Bs oscillation bound, 3) also added a short paragraph on page 5 comparing our results to those in the 2000 Particle Data Book article by Gilman et. al. and a footnote (#28) concerning the comparison with the scaning method of Ref 16

Various methods are discussed for obtaining the CKM angle gamma through the interference of the charged B-meson decay channels B- -> K- D0 and B- -> K- D0-bar where the D0 and D0-bar decay to common final states. It is found that choosing final states which are not CP eigenstates can lead to large direct CP violation which can give significant bounds on gamma without any theoretical assumptions. If two or more modes are studied, gamma may be extracted with a precision on the order of +/-15 degrees given about 10^8 B-mesons. We also discuss the case of three body decays of the D0 where additional information may be obtained from the distribution of the D0 decay products and consider the impact of D-D-bar oscillations., Comment: 51 pages 8 figures, typo in equation 33 corrected

CP violation in top physics is reviewed. The Standard Model has negligible effects, consequently CP violation searches involving the top quark may constitute the best way to look for physics beyond the Standard Model. Non-standard sources of CP violation due to an extended Higgs sector with and without natural flavor conservation and supersymmetric theories are discussed. Experimental feasibility of detecting CP violation effects in top quark production and decays in high energy e+ e-, gamma-gamma, mu+ mu-, pp and p-bar p colliders are surveyed. Searches for the electric, electro-weak and the chromo-electric dipole moments of the top quark in e+ e- -> t-bar t and in p p -> t-bar t X are descibed. In addition, other mechanisms that appear promising for experiments, e.g., tree-level CP violation in e+ e- -> t-bar t h, t-bar t Z, t-bar t nu_e-bar nu_e and in the top decay t -> b tau nu_tau and CP violation driven by s-channel Higgs exchanges in p p, gamma gamma, mu+ mu- -> t-bar t etc., are also discussed., Comment: 253 pages, 70 figures, A 2-up version of this postscript file may be obtained at http://thy.phy.bnl.gov/~soni/topreview.html

We consider the production of high invariant mass jet pairs at hadron colliders as a test for TeV scale gravitational effects. We find that this signal can probe effective Planck masses of about 10 TeV at the LHC with center of mass energy of 14 TeV and 1.5 TeV at the Tevatron with center of mass energy of 2 TeV. These results are compared to analogous scattering processes at leptonic colliders., Comment: 15 pages with 3 figures

We consider the production of gravitons via two photon and electron-photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We show that at electron-positron colliders, the processes l+l- -> l+ l- graviton, with l=e, mu, can lead to a new signal of low energy gravity of the form l+l- -> l+l- + missing energy which is well above the Standard Model background. For example, with two extra dimensions at the Next Linear Collider with a center of mass energy of 500 or 1000 GeV, hundreds to thousands such l+ l- graviton events may be produced if the scale of the gravitational interactions, M_D, is around a few TeV. At a gamma-electron collider, more stringent bounds may be placed on M_D via the related reaction e^-\gamma -> e^- graviton. For instance, if a 1TeV electron positron collider is converted to an electron-photon collider, a bound of ~10TeV may be placed on the scale M_D if the number of extra dimensions delta=2 while a bound of ~4TeV may be placed if delta=4., Comment: 25 pages 6 figures, minor changes made in the text and changes in references

We consider the scattering amplitudes of the form V_1 V_2 -> V_3 V_4, where V_i=\gamma, Z, W or g(=gluon) are the Standard Model gauge bosons, due to graviton exchange in Kaluza-Klein theories with large extra dimensions. This leads to a number of experimentally viable signatures at high energy leptonic and hadronic colliders. We discuss the observability or future limits on the scale of the gravitational interactions (m_D), that may be obtained at an e+e- Next Linear Collider (NLC) and at the LHC, by studying some of these type of gauge boson scattering processes. We find that the attainable limits through these type of processes are: m_D > 3 TeV at the NLC and m_D > 6 TeV at the LHC., Comment: 27 pages, plain latex, 7 figures embadded in the text using epsfig

We consider the production of gravitons via two photon fusion in Kaluza-Klein theories which allow TeV scale gravitational interactions. We find that the processes l+ l- to l+ l- + graviton, with l=electron or muon can put quite stringent bounds on such theories. For example, with two extra dimensions at the Next Linear Collider with a center of mass energy of 500 (1000) GeV attainable bounds on the scale of the gravitational interactions can reach about 6 (9) TeV., Comment: 17 pages, 4 figures; an error in the references was corrected

A general analysis for B decays to two pseudoscalars, involving ten modes, is presented. A simple model for final state interactions and rescattering effects is proposed. We show how the data can be used to deduce important information on electroweak penguins (EWP), rescattering and color suppression effects and on the CKM parameters in a largely model independent way by using chisquared-minimization. We find that the current data suggests the presence of color-suppressed tree at levels somewhat larger than simple theoretical estimates. Once the data improves the extraction of alpha and/or gamma may become feasible with this method as we illustrate with the existing data., Comment: In this version we have (1) clairified the relationship of our model with SU(3) identities (2)Used updated CLEO data (3)The correlation of electroweak penguins color suppressed tree and rescattering effects to individual modes is more clearly explained

We derive constraints for $B\to VV$ modes ($V= vector meson) that allow aquantitative assessment of the contributions from electroweak penguins (EWP) and/or new physics. Interplay of direct CP with oscillation studies then leads to the extraction of the angles alpha and gamma, using B--> K* omega rho and B--> rho omega (phi) respectively, if by using our constraint equations it can be experimentally demonstrated that color-suppressed EWP are small., Comment: 12 pages, 0 figures; revised and expanded

A systematic experimental search for two-body hadronic decays of the b-quark of the type b to quark + meson is proposed. These reactions have a well defined experimental signature and they should be theoretically cleaner compared to exclusive decays. Many modes have appreciable branching ratios and partial rate asymmetries may also be quite large (about 8-50%) in several of them. In a few cases electroweak penguins appear to be dominant and may be measurable. CP violating triple correlation asymmetries provide a clean test of the Standard Model., Comment: 12 pages 1 figure 1 table

We consider the strong rescattering effects that can occur in the decays such as B -> K pi, K* pi, K rho... and their impact on direct CP violation in these modes. First we discuss, in general, how the CPT theorem constrains the resulting pattern of partial rate asymmetries leading to different brands of direct CP. Traditional discussions have centered around the absorptive part of the penguin graph which has Delta I=0 in b -> s transitions and as a result causes ``simple'' CP violation; long-distance final state rescattering effects, in general, will lead to a different pattern of CP: ``compound'' CP violation. Predictions of simple CP are quite distinct from that of compound CP. Final states rescattering phases in B decays are unlikely to be small possibly causing large compound CP violating partial rate asymmetries in these modes. CPT theorem requires a cancellation of PRA due to compound CP amongst the $K\pi$ states themselves; thus there can be no net cancellation with other states such as K*\pi, K\rho etc. Therefore, each class of such modes, namely K pi, K rho, K^*pi, K a_1 etc. can have large direct CP emanating from rescattering effects. Various repercussions for the angle $\gamma$ are also discussed., Comment: 45 pages; 5 figures. In replacement we have : 1) corrected many typos, 2) added references, 3) decided to subdivide Simple CP into 2 categories and 4) Modified figure 3 to explain that

In this talk I will discuss the extraction of the CKM angle $\gamma$ at B-factories through the interference of the subprocesses $B^-\to K^- D^0$ and $B^- \to K^-\bar D^0$. This seemingly impossible interference may be accomplished by allowing both $D^0$ and $\bar D^0$ to decay to a common final state. If only CP eigenstate decay modes of the $D$ are considered, the branching ratio for $B^- \to \bar D^0 K^-$ must be experimentally I describe why this determination is likely to be experimentally impossible. On the other hand, if more general $D$ decays are considered, the angle $\gamma$ may then be determined. In fact, it is possible that a reasonable determination of $\gamma$ may be made with O(10^8) B's., Comment: 5 pages, 0 figures, Conference Proceedings

Jenkins has pointed out that the process $t\to cW^+W^-$ is GIM suppressed in the standard model. In this note, we calculate the branching ratio for a wide range of models, in which the decay occurs at tree level through exchange of a scalar, fermion or vector. In the case of scalar exchange, a scalar mass between $2m_W$ and 200 GeV leads to a resonant enhancement, giving a branching ratio as high as a few tenths of a percent. We then note that all of these models will also allow $W^+W^-\to \bar{t}c+t\bar{c}$, and we calculate the single-top/single-charm production rate at the LHC. The rates aren't negligibly small, but the background from single-top/single-bottom production will probably swamp the signal., Comment: 17 pages, 7 figures

Attributing the recent CLEO discovery of $B \to \eta' + X_s$ to originate (primarily) from the fragmentation of an off-shell gluon ($g^*$) via $b \to s + g^*$, $g^* \to g + \eta'$, we emphasize that many such states ($X_g$) should materialize. Indeed the hadronic fragments ($X_g$) of $g^*$ states are closely related to those seen in $\psi \to \gamma (\phi, \omega) + X_g$. A particular final state of considerable interest is $X_g=K^+K^-$. Signals from such states in $B$ decays can be combined to provide a very sensitive search for CP violating phase(s) from non-standard physics. The method should work even if the contribution of these source(s) to the rates is rather small ($\sim10%$) to the point that a comparison between theory and experiment may find it extremely difficult to reveal the presence of such a new physics., Comment: 16 pages, 5 figures

Mechanisms for the observed large $Br(B \to \eta' +X_s)$ are examined. We propose that the dominant fraction of the $B \to \eta' +X_s$ rate is due mainly to $b \to s g^*$, where $g^*$ is an off-shell gluon, followed by $g^* \to g\eta'$ via the anomalous coupling of the $\eta'$ to two gluons. The calculated rate for $B \to \eta'+X_s$ is in rough accord with experiment using a fairly constant glue-glue-$\eta'$ form factor. This behavior of the form factor may be indicative of glueball dominance of the channel. Searches via the modes $\eta' h^+h^-$ ($h=\pi$ or $K$) may be worthwhile. Charmonia contributions [i.e $B \to \eta_c, \psi (\to \eta'+X) +X_s$] can only account for at most 20% of the central value of the signal. Implications for $B \to \eta' +X_d$ and for the corresponding $\eta$ modes are also given., Comment: 19 pages, 5 figures