Three heavy jet events at hadron colliders as a sensitive probe of the Higgs sector

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.

Muon anomalous magnetic moment in the standard model with two Higgs doublets

The muon anomalous magnetic moment is investigated in the standard model with two Higgs doublets (S2HDM) motivated from spontaneous CP violation. Thus all the effective Yukawa couplings become complex. As a consequence of the non-zero phase in the couplings, the one loop contribution from the neutral scalar bosons could be positive and negative relying on the CP phases. The interference between one and two loop diagrams can be constructive in a large parameter space of CP-phases. This will result in a significant contribution to muon anomalous magnetic moment even in the flavor conserving process with a heavy neutral scalar boson ($m_h \sim$ 200 GeV) once the effective muon Yukawa coupling is large ($|\xi_\mu|\sim 50$). In general, the one loop contributions from lepton flavor changing scalar interactions become more important. In particular, when all contributions are positive in a reasonable parameter space of CP phases, the recently reported 2.6 sigma experiment vs. theory deviation can be easily explained even for a heavy scalar boson with a relative small Yukawa coupling in the S2HDM.Comment: 8 pages, RevTex file, 5 figures, published version Phys. Rev. D 54 (2001) 11501

Exploring flavor structure of supersymmetry breaking from rare B decays and unitarity triangle

We study effects of supersymmetric particles in various rare B decay processes as well as in the unitarity triangle analysis. We consider three different supersymmetric models, the minimal supergravity, SU(5) SUSY GUT with right-handed neutrinos, and the minimal supersymmetric standard model with U(2) flavor symmetry. In the SU(5) SUSY GUT with right-handed neutrinos, we consider two cases of the mass matrix of the right-handed neutrinos. We calculate direct and mixing-induced CP asymmetries in the b to s gamma decay and CP asymmetry in B_d to phi K_S as well as the B_s--anti-B_s mixing amplitude for the unitarity triangle analysis in these models. We show that large deviations are possible for the SU(5) SUSY GUT and the U(2) model. The pattern and correlations of deviations from the standard model will be useful to discriminate the different SUSY models in future B experiments.Comment: revtex4, 36 pages, 10 figure

B->eta(') Form Factors in QCD

We calculate the semileptonic form factors $f_+^{B\to \eta}(q^2)$ and $f_+^{B\to \eta'}(q^2)$ from QCD sum rules on the light-cone (LCSRs), to NLO in QCD, and for small to moderate q^2, $0\leq q^2\leq 16 {\rm GeV}^2$. We include in particular the so-called singlet contribution, i.e.\ weak annihilation of the B meson with the emission of two gluons which, thanks to the U(1)$_{\rm A}$ anomaly, couple directly to \etap. This effect is included to leading-twist accuracy. This contribution has been neglected in previous calculations of the form factors from LCSRs. We find that the singlet contribution to $f_+^{B\to \eta'}$ can be up to 20%, while that to $f_+^{B\to \eta}$ is, as expected, much smaller and below 3%. We also suggest to measure the ratio ${\cal B}(B\to\eta' e \nu)/{\cal B}(B\to \eta e \nu)$ to better constrain the size of the singlet contribution.Comment: 21 pages; version to appear in JHE

CP asymmetries in the supersymmetric trilepton signal at the LHC

In the CP-violating Minimal Supersymmetric Standard Model, we study the production of a neutralino-chargino pair at the LHC. For their decays into three leptons, we analyze CP asymmetries which are sensitive to the CP phases of the neutralino and chargino sector. We present analytical formulas for the entire production and decay process, and identify the CP-violating contributions in the spin correlation terms. This allows us to define the optimal CP asymmetries. We present a detailed numerical analysis of the cross sections, branching ratios, and the CP observables. For light neutralinos, charginos, and squarks, the asymmetries can reach several 10%. We estimate the discovery potential for the LHC to observe CP violation in the trilepton channel.Comment: 39 pages, 8 figures, version to appear in EPJC, discussion(s) added, typo in (D.79), (D.118) corrected, new Fig. 7; The European Physical Journal C, Volume 72, Issue 3, 201

Phenomenological aspects of the exotic TT quark in 331 models

In the context of 331 models we analyze the phenomenology of exotic $T$ quarks with electric charge 2/3. We establish bounds for the corresponding masses and mixing angles and study the decay modes $T\to bW$, $tZ$ and $qH$. It is found that the decays into scalars are strongly dependent on the model parameters, and can be the dominant ones in a scenario with approximate flavor symmetry.Comment: 11 pages, 2 figure

Model-independent analysis of Higgs spin and CP properties in the process e+e−→ttˉΦe^+ e^- \to t \bar t \Phi

In this paper we investigate methods to study the $t\bar{t}$ Higgs coupling. The spin and CP properties of a Higgs boson are analysed in a model-independent way in its associated production with a $t\bar{t}$ pair in high-energy $e^+e^-$ collisions. We study the prospects of establishing the CP quantum numbers of the Higgs boson in the CP-conserving case as well as those of determining the CP-mixing if CP is violated. We explore in this analysis the combined use of the total cross section and its energy dependence, the polarisation asymmetry of the top quark and the up-down asymmetry of the antitop with respect to the top-electron plane. We find that combining all three observables remarkably reduces the error on the determination of the CP properties of the Higgs Yukawa coupling. Furthermore, the top polarisation asymmetry and the ratio of cross sections at different collider energies are shown to be sensitive to the spin of the particle produced in association with the top quark pair

Search for the lepton flavor violating decay A^0/H^0 --> tau^{+/-} mu^{+/-} at hadron colliders

In the two Higgs doublet model type III and in several other extensions of the Standard Model, there are no discrete symmetries that suppress flavor changing couplings at tree level. The experimental observation of the nu_mu -- nu_tau flavor oscillation may suggest the non-conservation of lepton number. This would lead to the decay of the type A^0/H^0 --> tau^{+/-} mu^{+/-}. We determine the present low energy limit on lepton flavor violating (LFV) couplings from the muon g-2 measurement and discuss the prospects for detecting lepton flavor violating decays at the TeVatron and at the Large Hadron Collider. The achievable bounds on the LFV coupling parameter lambda_{tau mu} are presented.Comment: 19 pages, 21 figures. Updated version takes into account the recent results on the muon g-2 measurements. Submitted to Phys. Rev. D. Added minor corrections from a refere

Effect of lactation stage and concurrent pregnancy on milk composition in the bottlenose dolphin

Although many toothed whales (Cetacea: Odontoceti) lactate for 2–3 years or more, it is not known whether milk composition is affected by lactation stage in any odontocete species. We collected 64 pooled milk samples spanning 1–30 months postpartum from three captive bottlenose dolphins Tursiops truncatus. Milks were assayed for water, fat, crude protein (TN × 6.38) and sugar; gross energy was calculated. Ovulation and pregnancy were determined via monitoring of milk progesterone. Based on analysis of changes in milk composition for each individual dolphin, there were significant increases (P<0.05) in fat (in all three dolphins) and crude protein (in two of three), and a decrease (P<0.05) in water (in two of three) over the course of lactation, but the sugar content did not change. In all three animals, the energy content was positively correlated with month of lactation, but the percentage of energy provided by crude protein declined slightly but significantly (P<0.05). At mid-lactation (7–12 months postpartum, n=17), milk averaged 73.0±1.0% water, 12.8±1.0% fat, 8.9±0.5% crude protein, 1.0±0.1% sugar, 1.76±0.09 kcal g−1 (=7.25 kJ g−1) and 30.3±1.3% protein:energy per cent. This protein:energy per cent was surprisingly high compared with other cetaceans and in relation to the growth rates of calves. Milk progesterone indicated that dolphins ovulated and conceived between 413 and 673 days postpartum, following an increase in milk energy density. The significance of these observed compositional changes to calf nutrition will depend on the amounts of milk produced at different stages of lactation, and how milk composition and yield are influenced by sampling procedure, maternal diet and maternal condition, none of which are known