Search results for "Functional analysis"
showing 10 items of 1059 documents
Heavy Quark Symmetries: Molecular partners of theX(3872) andZb(10610)/Zb′(10650)
2014
In this work, we have made use of the identification of the X (3872) and Z b (10610)/Z b ′(10650) as heavy meson-heavy antimeson molecules to establish some consequences derived from the symmetries that these heavy meson-heavy antimeson systems must have. We show the most general effective lagrangian that respects these symmetries only depends on four undetermined low energy constants (LECs), which will be fitted to reproduce the experimental data about the resonances we are identifying as molecular states. Then, we obtain a whole new set of states in the spectrum that could also be thought as heavy meson-heavy antimeson molecules. Finally, using another different symmetry: Heavy Antiquark-…
Optimal control of a three-level quantum system by laser fields plus von Neumann measurements
2008
International audience; We investigate the control of a three-level quantum system by laser fields assisted by von Neumann measurements. We consider a system which is not completely controllable by unitary evolution but which becomes controllable if particular measurements are used. The optimal control is defined from a cost functional which takes into account the measurements. The cost corresponds either to the minimization of the duration of the control or to the minimization of the energy of the laser field. Using the Pontryagin maximum principle, we determine the optimal control which steers the system from a given initial state toward a desired target state. This allows one to determin…
Prediction of anI=1DD¯*state and relationship to the claimedZc(3900),Zc(3885)
2014
We study here the interaction of $D{\overline{D}}^{*}$ in the isospin $I=1$ channel in light of recent theoretical advances that allow us to combine elements of the local hidden gauge approach with heavy quark spin symmetry. We find that the exchange of light $q\overline{q}$ is Okubo-Zweig-Iizuka (OZI) suppressed and thus we concentrate on the exchange of heavy vectors and of two pion exchange. The latter is found to be small compared to the exchange of heavy vectors, which then determines the strength of the interaction. A barely $D{\overline{D}}^{*}$ bound state decaying into ${\ensuremath{\eta}}_{c}\ensuremath{\rho}$ and $\ensuremath{\pi}J/\ensuremath{\psi}$ is found. At the same time we…
The Hunt for New Physics in the Flavour Sector with up vector-like quarks
2012
We analyse the possible presence of New Physics (NP) in the Flavour Sector and evaluate its potential for solving the tension between the experimental values of $\AJPKs$ and $\BTNu$ with respect to the Standard Model (SM) expectations. Updated model independent analyses, where NP contributions are allowed in Bd - anti-Bd and Bs - anti-Bs transitions, suggest the need of New Physics in the $bd$ sector. A detailed analysis of recent Flavour data is then presented in the framework of a simple extension of the SM, where a $Q=2/3$ vector-like isosinglet quark is added to the spectrum of the SM. Special emphasis is given to the implications of this model for correlations among various measurable …
Hidden beauty baryon states in the local hidden gauge approach with heavy quark spin symmetry
2013
Using a coupled-channel unitary approach, combining the heavy quark spin symmetry and the dynamics of the local hidden gauge, we investigate the meson-baryon interaction with hidden beauty and obtain several new states of N around 11 GeV. We consider the basis of states eta (b) N, I'N, BI > (b) , BI pound (b) , B (*) I > (b) , B (*) I pound (b) , B (*) I pound (b) (*) and find four basic bound states which correspond to BI pound (b) , BI pound (b) (*) , B (*) I pound (b) and B (*) I pound (b) (*) , decaying mostly into eta (b) N and I'N and with a binding energy about 50-130 MeV with respect to the thresholds of the corresponding channel. All of them have isospin I = 1/2 , and we find no bo…
Resonant structure and flavour tagging in the Bπ±system using fully reconstructed B decays
1998
Abstract Starting from a sample of four million hadronic Z decays collected with the ALEPH detector at LEP, 404 charged and neutral B mesons are fully reconstructed and used to look for resonant structure in the Bπ system. An excess of events is observed above the expected background in the Bπ mass spectrum at a mass ≈5.7 GeV/c 2 , consistent with the production and decay to B (∗) π of the B ∗∗ states predicted by Heavy Quark Symmetry (HQS). In the framework of HQS, it is found that the mass of the B 2 ∗ state is (5739 + 8 −11 ( stat ) +6 −4 ( syst )) MeV/c 2 and the relative production rate of the B ∗∗ system is BR(b→B ∗∗ →B (∗) π)/BR(b→B u,d )=(31±9 (stat) +6 −5 (syst)) % . In the same sa…
Generalized screened potential model
2014
A new non relativistic quark model to calculate the spectrum of heavy quark mesons is developed. The model is based on an interquark potential interaction that implicitly incorporates screening effects from meson-meson configurations. An analysis of the bottomonium spectrum shows the appearance of extra states as compared to conventional non screened potential models.
Three-body final state interaction in η→ 3π updated
2017
In view of the recent high-statistic KLOE data for the η→π+π−π0 decay, a new determination of the quark mass double ratio has been done. Our approach relies on a dispersive model that takes into account rescattering effects between three pions via subenergy unitarity. The latter is essential to reproduce the Dalitz plot distribution. A simultaneous description of the KLOE and WASA-at-COSY data is achieved in terms of just two real parameters. From a global fit, we determine Q=21.6±1.1. The predicted slope parameter for the neutral channel α=−0.025±0.004 is in reasonable agreement with the PDG average value.
Strong pionic decays of baryons from a spectroscopic quark model
1996
From a refined non-relativistic quark model that fits the baryonic low-energy spectrum the study of strong pion decay processes within an elementary emission model scheme points out the need of incorporating size-contributing components into the baryon wave functions. In particular the effect of a (qqq ) component is investigated in the framework of a quark pair creation model.
Transverse-Momentum Distributions and Spherical Symmetry
2011
Transverse-momentum dependent parton distributions (TMDs) are studied in the framework of quark models. In particular, quark model relations among TMDs are reviewed and their physical origin is discussed in terms of rotational-symmetry properties of the nucleon state in its rest frame.