Bottom baryons

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.

A search is performed for the decay Λb → pKη′ using pp collision data collected with the LHCb detector at centre-of-mass energies of √ s = 7 TeV and √ s = 8 TeV, corresponding to an integrated luminosity of 3 fb−1. The search is performed in two decay channels; the η′ is reconstructed through the decays η′→ π+π−γ and η′→ π+π−η . In the η′→ π+π−γ decay channel 117 ± 15(stat.) ± 10(sys.) signal events are observed and 45 ± 8(stat.) ± 2(sys.) signal events are observed in the η′→ π+π−η decay channel. The combined statistical significance of these signals is 12.0σ, therefore this is the first observation of the decay Λb→ pKη′ . The branching fraction of the decay Λb→ pKη′ is measured relative to the decay B+→ K+η′ . The ratio of branching fractions is measured to be B(Λb→ pKη′) B(B+→ K+η′) = 0.120± 0.013(stat.)± 0.013(sys.). Using the world average value for the branching fraction of the decay B+→ K+η′ [1], the branching fraction of Λb→ pKη′ is measured to be B(Λb→ pKη′) = 8.48± 0.88(st...

The magnetic moments of heavy sextet J P = 1 2 + baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.

We report measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using a data sample corresponding to 1 fb −1 of integrated luminosity, we obtain the first measurements of direct CP violation in bottom strange mesons, ACP (B 0 s → K − π +) = +0.39 ± 0.15 (stat) ± 0.08 (syst), and bottom baryons, ACP (Λ 0 b → pπ −) = +0.03 ± 0.17 (stat) ± 0.05 (syst) and ACP (Λ 0 b → pK −) = +0.37 ± 0.17 (stat) ± 0.03 (syst). In addition, we measure CP violation in B 0 → K + π − decays with 3.5σ significance, ACP (B 0 → K + π −) = −0.086 ± 0.023 (stat) ± 0.009 (syst), in agreement with the current world average. Measurements of branching fractions of B 0 s → K + K − and B 0 → π + π − decays are also updated.

We discuss the possible searching for the oscillation by coherent ΛΛ̅ production in J/ψ→ΛΛ̅ decay process. The sensitivity of measurement of Λ - Λ̅ oscillation in the external field at BES-III experiment is considered. These considerations indicate an alternative way to probe the Δ B =2 amplitude in addition to neutron oscillation experiments. Both coherent and time-dependent information can be used to extract Λ -Λ̅ oscillation parameter. With one year's luminosity at BES-III, we can set an upper limit of δ m < 10^-15 MeV at 90 to about 10^-6 s of - oscillation time.

An angular analysis of Λ 0 b → J/ψ Λ decays is performed using a data sample corresponding to 1.0 fb -1 collected in pp collisions at √ s = 7 TeV with the LHCb detector at the LHC. A parity violating asymmetry parameter characterising the Λ 0 b → J/ψ Λ decay of 0.05 ± 0.17 ± 0.07 and a Λ 0 b transverse production polarisation of 0.06 ± 0.07 ± 0.02 are measured, where the first uncertainty is statistical and the second systematic.

An angular analysis of Λ 0 b → J/ψ Λ decays is performed using a data sample corresponding to 1.0 fb −1 collected in pp collisions at √ s = 7 TeV with the LHCb detector at the LHC. A parity violating asymmetry parameter characterising the Λ 0 b → J/ψ Λ decay of 0.05 ± 0.17 ± 0.07 and a Λ 0 b transverse production polarisation of 0.06 ± 0.07 ± 0.02 are measured, where the first uncertainty is statistical and the second systematic.

A hybrid operator splitting method is developed for computations of two-dimensional transverse magnetic Maxwell equations in media with multiple random interfaces. By projecting the solutions into the random space using the polynomial chaos (PC) projection method, the deterministic and random parts of the solutions are solved separately. There are two independent stages in the algorithm: the Yee scheme with domain decomposition implemented on a staggered grid for the deterministic part and the Monte Carlo sampling in the post-processing stage. These two stages of the algorithm are subject of computational studies. A parallel implementation is proposed for which the computational cost grows linearly with the number of random interfaces. Output statistics of Maxwell solutions are obtained including means, variance and time evolution of cumulative distribution functions (CDF). The computational results are presented for several configurations of domains with random interfaces. The nove...

Branching ratios, lepton forward-backward asymmetries, and lepton polarization asymmetries for the flavor-changing neutral current (FCNC) dileptonic decays of the Λb baryon to the ground state and a number of excited state Λ baryons are calculated using form factors extracted using wave functions from a constituent quark model. The SM branching ratios for the transition to the ground state calculated using these quark model form factors are consistent with the recent measurement reported by the LHCb collaboration. It is shown that the lepton polarization asymmetries are largely insensitive to the transition form factors and, therefore, to the effects of QCD in the nonperturbative regime. These observables can therefore provide somewhat model independent ways of extracting various combinations of the Wilson coefficients.

Hadronic form factors for the rare weak transitions Λ b → Λ (*) are calculated using a nonrelativistic quark model. The form factors are extracted in two ways. An analytic extraction using single component wave functions (SCA) with the quark current being reduced to its nonrelativistic Pauli form is employed in the first method. In the second method, the form factors are extracted numerically using the full quark model wave function (MCN) with the full relativistic form of the quark current. Although there are differences between the two sets of form factors, both sets satisfy the relationships expected from the heavy quark effective theory (HQET). Differential decay rates, branching ratios and forward-backward asymmetries (FBAs) are calculated for the dileptonic decays Λ b → Λ (*) ℓ + ℓ − , for transitions to both ground state and excited daughter baryons. Inclusion of the long distance contributions from charmonium resonances significantly enhances the decay rates. In the MCN model the Λ(1600) mode is the dominant mode in the µ channel when charmonium resonances are considered; the Λ(1520) mode is also found to have a comparable branching ratio to that of the ground state in the µ channel.

In previous work we have introduced model predictive control (MPC) for max-plus-linear and max-min-plus(scaling) discrete-event systems. For max-plus-linear systems there are efficient algorithms to solve the corresponding MPC optimization problems. However, previously, for max-min-plus(-scaling) systems the only approach was to consider a limited subclass of decoupled max-min-plus systems or to use nonlinear nonconvex optimization algorithms, which are not efficient if the size of the system or the MPC optimization problem is large. In this paper, we present a more efficient approach that is based on canonical forms for max-min-plus-scaling functions and in which the MPC optimization problem is reduced to a set of linear programming problems.

In previous work we have introduced model predictive control (MPC) for max-plus-linear and max-min-plus(scaling) discrete-event systems. For max-plus-linear systems there are efficient algorithms to solve the corresponding MPC optimization problems. However, previously, for max-min-plus(-scaling) systems the only approach was to consider a limited subclass of decoupled max-min-plus systems or to use nonlinear nonconvex optimization algorithms, which are not efficient if the size of the system or the MPC optimization problem is large. In this paper, we present a more efficient approach that is based on canonical forms for max-min-plus-scaling functions and in which the MPC optimization problem is reduced to a set of linear programming problems.

The weak decays of charmed baryon multiplets into ground state baryons and mesons are investigated using current algebra technique. Some of the interesting results on the partial decays= rates and the asymmetry parameters for the ∆C=∆S=-1 mode are calculated and consequences discussed.

We obtain exact solutions of the (2+1) dimensional Dirac oscillator in a homogeneous magnetic field within a minimal length (∆x0 = √ β), or generalized uncertainty principle (GUP) scenario. This system in ordinary quantum mechanics has a single left-right chiral quantum phase transition (QPT). We show that a non zero minimal length turns on a infinite number of quantum phase transitions which accumulate towards the known QPT when β → 0. It is also shown that the presence of the minimal length modifies the degeneracy of the states and that in this case there exist a new class of states which do not survive in the ordinary quantum mechanics limit β → 0.

We discuss various topics in the theory of heavy baryon decays. Among these are recent applications of the Relativistic Three Quark Model to semileptonic, non-leptonic, one-pion and one-photon transitions among heavy baryons, new higher order perturbative results on the correlator of two heavy baryon currents and on the semi-inclusive decay Λ b → X c + D

We introduce and study the properties of a class of coherent states for the group SU(1,1) X SU(1,1) and derive explicit expressions for these using the Clebsch-Gordan algebra for the SU(1,1) group. We restrict ourselves to the discrete series representations of SU(1,1). These are the generalization of the `Barut Girardello' coherent states to the Kronecker Product of two non-compact groups.The resolution of the identity and the analytic phase space representation of these states is presented. This phase space representation is based on the basis of products of `pair coherent states' rather than the standard number state canonical basis. We discuss the utility of the resulting `bi-pair coherent states' in the context of four-mode interactions in quantum optics.

The main objective of this work consists of obtaining a new robust and stable Model Predictive Control (MPC). One widely used technique for improving robustness in MPC consists of the Min-Max optimization, where an analogy can be established with the Bounded Data Uncertainties (BDU) method. The BDU is a regularization technique for least-squares problems by taking into account the uncertainty bounds. So BDU both improves robustness in MPC and offers a guided way of tuning the empirically tuned penalization parameter for the control effort in MPC due to the duality that the parameter coincides with the regularization one in BDU. On the other hand, the stability objective is achieved by the use of terminal constraints, in particular the Constrained Receding-Horizon Predictive Control (CRHPC) algorithm, so the original CRHPC-BDU controller is stated, which presents a better performance from the point of view of robustness and stability than a standard MPC.

In this paper we study the lepton polarization asymmetry for the simileptonic OZI-forbidden annihilation B^-_c->\eta' \ell^- \bar{\nu} decay where \ell=\mu, \tau. Our results show that the branching ratio turn out to be of order 10^{-4}. Beside, we find that longitudinal, transversal and normal components of lepton polarizations can be measured for both \mu and \tau decay modes in the future experiments at the LHC.

We examine the unparticle CP-conserving phase effects on the direct CP asymmetry for both polarized and unpolarized leptons in the inclusive b→dℓ+ℓ- transition, where the flavor-changing neutral currents are forbidden at tree level but are induced by one-loop penguin diagrams. The averaged polarized and unpolarized CP asymmetries depict strong dependency on the unparticle parameters. In particular, a sizable discrepancy corresponding to the standard model is achieved when the scale dimension value is 1<dU<2. We see that the unparticle stuff significantly enhances, suppresses, or changes the sign of the CP asymmetry depending on the definite value of the scaling dimension dU. Especially, when dU˜1.1 the CP asymmetries vanish.

In the mfimle mass limit one can separate unambtgously positive and negative panty contributions to baryomc correlators. We examine the rehabthty of the baryon sum rules m the heavy quark effective theory. Finite mass correcUons are found to be large whde the pred~cUons remain quahtat~ve.

The magnetic moments of heavy sextet $J^P = {1\over 2}^+$ baryons are calculated in framework of the light cone QCD sum rules method. Linearly independent relations among the magnetic moments of these baryons are obtained. The results for the magnetic moments of heavy baryons obtained in this work are compared with the predictions of the other approaches.

We analyse the Lorentz structures of weak decay matrix elements between meson states of arbitrary spin. Simplifications arise in the transition amplitudes for a heavy meson decaying into the light one via a Bethe-Salpeter approach which incorporates heavy quark symmetry. Phenomenological consequences of our results on several semileptonic, nonleptonic and flavour changing neutral current-induced decays of heavy flavoured mesons are derived and discussed.

Assuming Coulomb-like as well as confining scalar potential, we have solved Shrödinger equation perturbatively in 1/m Q with a heavy quark mass m Q . The lowest order equation is examined carefully. Mass levels are fitted with experimental data for D/B mesons at each level of perturbation. Meson wave functions obtained thereby can be used to calculate ordinary form factors as well as Isgur-Wise functions for semileptonic weak decays and other physical quantities. All the above calculations are expanded in 1/m Q order by order to determine parameters as well as to compare with results of Heavy Quark Effective Theory.

π and η decay modes of light baryon resonances are investigated within a chiral quark model whose hyperfine interaction is based on Goldstone-boson exchange. For the decay mechanism a modified version of the 3 P0 model is employed. Our primary aim is to provide a further test of the recently proposed Goldstone-boson-exchange constituent quark model. We compare the predictions for π and η decay widths with experiment and also with results from a traditional one-gluon-exchange constituent quark model. The differences between nonrelativistic and semirelativistic versions of the constituent quark models are outlined. We also discuss the sensitivity of the results on the parametrization of the meson wave function entering the 3 P0 model.

We compute the leading order (in α s ) perturbative QCD and power (1/m 2 b ) corrections to the hadronic invariant mass and hadron energy spectra in the decay B → X s ℓ + ℓ − in standard model. The computations are carried out using the heavy quark expansion technique (HQET) and a perturbative-QCD improved Fermi motion (FM) model which takes into account B-meson wave-function effects. The corrections in the hadron energy (E H ) spectrum are found to be small over a good part of this spectrum in both methods. However, the expansion in 1/m b in HQET fails near the lower kinematic end-point and at the cc threshold. The hadronic invariant mass (S H ) spectrum is calculable only over a limited range S H >Λm B in the heavy quark expansion, whereΛ ≃ m B − m b . We also present results for the first two hadronic moments S n H and E n H , n = 1, 2, working out their sensitivity on the HQET and FM model parameters. For equivalent values of these parameters, the moments in these methods are remarkably close to each other. The constraints following from assumed values of S n H on the HQET parameters λ 1 andΛ are worked out. Data from the forthcoming B facilities could be used to measure the short-distance contribution in B → X s ℓ + ℓ − and constrain the HQET parameters λ 1 andΛ. This could be combined with complementary constraints from the decay B → Xℓν ℓ to determine these parameters precisely. We also study the effect of the experimental cuts, used recently by the CLEO collaboration in searching for the decay B → X s ℓ + ℓ − , on the branching ratios, hadron spectra and hadronic invariant mass moments using the FM model.

We provide the definition of the complete set of light-cone distribution amplitudes (LCDAs) for the ground state heavy bottom baryons with the spin-parities J P = 1/2 + and J P = 3/2 + in the heavy quark limit. We present the renormalization effects on the twist-2 light-cone distribution amplitudes and use the QCD sum rules to compute the moments of twist-2, twist-3, and twist-4 LCDAs. Simple models for the heavy baryon distribution amplitudes are analyzed with account of their scale dependence.

Branching ratios, lepton forward-backward asymmetries, and lepton polarization asymmetries for the flavor-changing neutral current (FCNC) dileptonic decays of the Λb baryon to the ground state and a number of excited state Λ baryons are calculated using form factors extracted using wave functions from a constituent quark model. The SM branching ratios for the transition to the ground state calculated using these quark model form factors are consistent with the recent measurement reported by the LHCb collaboration. It is shown that the lepton polarization asymmetries are largely insensitive to the transition form factors and, therefore, to the effects of QCD in the nonperturbative regime. These observables can therefore provide somewhat model independent ways of extracting various combinations of the Wilson coefficients.

We study some nonleptonic decays of Ab-baryon involving transition of a heavy to light quark, using nonrelativistic quark model for form factors. The decay rates for two such decays are consistent with the data available. Also these decays can give us information on the CKM matrix element [V~bl.

We discuss the generalized eigenvalue problem for computing energies and matrix elements in lattice gauge theory, including effective theories such as HQET. It is analyzed how the extracted effective energies and matrix elements converge when the time separations are made large. This suggests a particularly efficient application of the method for which we can prove that corrections vanish asymptotically as $\exp(-(E_{N+1}-E_n) t)$. The gap $E_{N+1}-E_n$ can be made large by increasing the number $N$ of interpolating fields in the correlation matrix. We also show how excited state matrix elements can be extracted such that contaminations from all other states disappear exponentially in time. As a demonstration we present numerical results for the extraction of ground state and excited B-meson masses and decay constants in static approximation and to order $1/m_b$ in HQET.

We derive generic formulas for the polarization density matrix of leptons produced in νN and ¯ {ν }N collisions and briefly consider some important particular cases. Next we employ the general formalism in order to include the final lepton mass and spin into the popular model by Rein and Sehgal for single pion neutrinoproduction.

Using the responsible form factors calculated via full QCD, we analyze the Λ b → Λℓ + ℓ − transition in the standard model containing fourth-generation quarks (SM4). We discuss the effects of the presence of the t ′ fourth-family quark on related observables like branching ratio, forward-backward asymmetry, baryon polarization as well as double-lepton polarization asymmetries. We also compare our results with those obtained in the SM as well as with predictions of the SM4 but using form factors calculated within heavy-quark effective theory. The obtained results on the branching ratio indicate that the Λ b → Λℓ + ℓ − transition is more probable in full QCD comparing to the heavy-quark effective theory. It is also shown that the results on all considered observables in the SM4 deviate considerably from the SM predictions when m t ′ ≥ 400 GeV.

Hadronic form factors for the rare weak transitions Λ b → Λ ( * ) are calculated using a nonrelativistic quark model. The form factors are extracted in two ways. An analytic extraction using single component wave functions (SCA) with the quark current being reduced to its nonrelativistic Pauli form is employed in the first method. In the second method, the form factors are extracted numerically using the full quark model wave function (MCN) with the full relativistic form of the quark current. Although there are differences between the two sets of form factors, both sets satisfy the relationships expected from the heavy quark effective theory (HQET). Differential decay rates, branching ratios and forward-backward asymmetries (FBAs) are calculated for the dileptonic decays Λ b → Λ ( * ) ℓ + ℓ − , for transitions to both ground state and excited daughter baryons. Inclusion of the long distance contributions from charmonium resonances significantly enhances the decay rates. In the MCN model the Λ(1600) mode is the dominant mode in the µ channel when charmonium resonances are considered; the Λ(1520) mode is also found to have a comparable branching ratio to that of the ground state in the µ channel. → N ( * ) were calculated using single component wave functions obtained from a variational diagonalization of a quark model Hamiltonian. In that calculation, quark operators were reduced to their nonrelativistic Pauli form. The decay rates obtained using the form factors extracted in that calculation were in reasonable agreement with experimental results for the semileptonic decays Λ b → Λ c ℓν ℓ and Λ c → Λℓν ℓ .