Publications (88)229.82 Total impact
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ABSTRACT: Chiral extrapolation of the $X(3872)$ binding energy is investigated using the modified Weinberg formulation of chiral effective field theory for the $D \bar{D}^*$ scattering. Given its explicit renormalisability, this approach is particularly useful to explore the interplay of the long and shortrange $D \bar{D}^*$ forces in the $X(3872)$ from studying the lightquark (pion) mass dependence of its binding energy. In particular, the parameterfree leadingorder calculation shows that the $X$pole disappears for unphysical large pion masses. On the other hand, without contradicting the naive dimensional analysis, the higherorder pionmassdependent contact interaction can change the slope of the binding energy at the physical point yielding the opposite scenario of a stronger bound $X$ at pion masses larger than its physical value. An important role of the pion dynamics and of the 3body $D\bar{D}\pi$ effects for chiral extrapolations of the $X$pole is emphasised. The results of the present study should be of practical value for the lattice simulations since they provide a nontrivial connection between lattice points at unphysical pion masses and the physical world.  [Show abstract] [Hide abstract]
ABSTRACT: We propose a practical parametrization for the line shapes of nearthreshold states compatible with all requirements of unitarity and analyticity. The coupledchannel system underlying the proposed parametrization includes a bare pole and an arbitrary number of elastic and inelastic channels treated fully nonperturbatively. The resulting formulas are general enough to be used for a simultaneous analysis of the data in all available production and decay channels of a given (system of) state(s) for a quite wide class of reactions. As an example, we fit the experimental data currently available for several decay channels for the charged $Z_b(10610)$ and $Z_b(10650)$ states in the spectrum of bottomonia and find a remarkably good overall description of the data.Physical Review Letters 07/2015; 115(20). DOI:10.1103/PhysRevD.92.014005 · 7.51 Impact Factor 
Article: Remarks on the study of the X(3872) from Effective Field Theory with PionExchange Interaction
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ABSTRACT: In a recent paper Phys.Rev.Lett. 111, 042002 (2013) (arXiv:1304.0846), the charmonium state X(3872) is studied in the framework of an effective field theory. In that work it is claimed that (i) the onepion exchange (OPE) alone provides sufficient binding to produce the X as a shallow bound state at the $D^0\bar{D}^{*0}$ threshold, (ii) shortrange dynamics (described by a contact interaction) provides only moderate corrections to the OPE, and (iii) the Xpole disappears as the pion mass is increased slightly and therefore the X should not be seen on the lattice, away from the pion physical mass point, if it were a molecular state. In this paper we demonstrate that the results of Phys.Rev.Lett. 111, 042002 (2013) (arXiv:1304.0846) suffer from technical as well as conceptual problems and therefore do not support the conclusions drawn by the authors.Physical Review D 01/2015; 91(3). DOI:10.1103/PhysRevD.91.034002 · 4.64 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Starting from the hypothesis that the X(3872) is a $D\bar D^*$ molecule, we discuss the radiative decays of the X(3872) into $\gamma J/\psi$ and $\gamma\psi'$ from an effective field theory point of view. We show that radiative decays are not sensitive to the longrange structure of the X(3872). In particular, contrary to earlier claims, we argue that the experimentally determined ratio of the mentioned branching fractions is not in conflict with a wave function of the X(3872) that is dominated by the $D\bar D^*$ hadronic molecular component.Physics Letters B 10/2014; 742. DOI:10.1016/j.physletb.2015.02.013 · 6.13 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Direct production of the charmoniumlike state $X(3872)$ in $e^+e^$ collisions is considered in the framework of the vector meson dominance model. An orderofmagnitude estimate for the width $\Gamma(X\to e^+e^)$ is found to be $\gtrsim$0.03 eV. The same approach applied to the $\chi_{c1}$ charmonium decay predicts the corresponding width of the order 0.1 eV in agreement with earlier estimates. Experimental perspectives for the direct production of the $1^{++}$ charmonia in $e^+e^$ collisions are briefly discussed.Physics Letters B 05/2014; 736. DOI:10.1016/j.physletb.2014.07.027 · 6.13 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: Direct production of the charmoniumlike state $X(3872)$ in $e^+e^$ collisions is considered in the framework of the vector meson dominance model. An orderofmagnitude estimate for the width $\Gamma(X\to e^+e^)$ is found to be $\gtrsim$0.03 eV. The same approach applied to the $\chi_{c1}$ charmonium decay predicts the corresponding width of the order 0.1 eV in agreement with earlier estimates. Experimental perspectives for the direct production of the $1^{++}$ charmonia in $e^+e^$ collisions are briefly discussed. 
Article: X(3872) as the 1 D 2 charmonium
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ABSTRACT: The 1 D 2 charmonium assignment for the X(3872) is considered, which is compatible with the 2+ quantum numbers, as favoured by the BABAR Collaboration analysis presented recently for the π + π  π 0 J/ψ decay mode. It is demonstrated that established properties of the X(3872) are in a drastic conflict with the 1 D 2 c assignment. Furthermore, it is argued that a combined analysis of the data for different decay channels of the X, with the help of theoretical formulae which meet a number of constraints imposed by phenomenology, results in a suitable description of the experimental data for the X compatible with its quantum numbers 1++.Physics of Atomic Nuclei 11/2013; 76(12). DOI:10.1134/S106377881322002X · 0.51 Impact Factor 
Article: SuperB Technical Design Report
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ABSTRACT: In this Technical Design Report (TDR) we describe the SuperB detector that was to be installed on the SuperB e+e high luminosity collider. The SuperB asymmetric collider, which was to be constructed on the Tor Vergata campus near the INFN Frascati National Laboratory, was designed to operate both at the Upsilon(4S) centerofmass energy with a luminosity of 10^{36} cm^{2}s^{1} and at the tau/charm production threshold with a luminosity of 10^{35} cm^{2}s^{1}. This high luminosity, producing a data sample about a factor 100 larger than present B Factories, would allow investigation of new physics effects in rare decays, CP Violation and Lepton Flavour Violation. This document details the detector design presented in the Conceptual Design Report (CDR) in 2007. The R&D and engineering studies performed to arrive at the full detector design are described, and an updated cost estimate is presented. A combination of a more realistic cost estimates and the unavailability of funds due of the global economic climate led to a formal cancelation of the project on Nov 27, 2012.  [Show abstract] [Hide abstract]
ABSTRACT: We explore the quarkmass dependence of the pole position of the X(3872) state within the molecular picture. The calculations are performed within the framework of a nonrelativistic Faddeevtype threebody equation for the $D\bar{D}\pi$ system in the $J^{PC}=1^{++}$ channel. The $\pi D$ interaction is parametrised via a $D^*$ pole, and a threebody force is included to render the equations well defined. Its strength is adjusted such that the X(3872) appears as a $D\bar{D}^*$ bound state 0.5 MeV below the neutral threshold. We find that the trajectory of the X(3872) depends strongly on the assumed quarkmass dependence of the shortrange interactions which can be determined in future lattice QCD calculations. At the same time we are able to provide nontrivial information on the chiral extrapolation in the $X$ channel.Physics Letters B 06/2013; 726(1). DOI:10.1016/j.physletb.2013.08.073 · 6.13 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We reexamine onepion exchange as a possible binding mechanism in the X(3872) charmoniumlike state and argue it to be not sufficiently binding for this purpose. We conclude therefore that other shortrange dynamics are responsible for the X formation.JETP Letters 12/2012; 97(2). DOI:10.1134/S0021364013020070 · 1.36 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We point out the physics opportunities of future highluminosity Bfactories at the Upsilon(5S) resonance and above. In this paper we discuss numerous interesting investigations, which can be performed in the e+e centreofmass energy region from the Upsilon(5S) and up to 11.5 GeV, where an efficient data taking operation should be possible with the planned Bfactories. These studies include abundant Bs production and decay properties; independent confirmation and if found, exhaustive exploration of Belle's claimed charged bottomonia; clarification of puzzles of interquarkonium dipion transitions; extraction of the light quark mass ratio from hadronic Upsilon(5S) decays; analysis of quarkonium and exotic internal structure from open flavour decays, leading to severe SU(3) symmetry violations; clarification of whether a hybrid state has similar mass to the Upsilon(5S) bottomonium, making it a double state; searches for molecular/tetraquark states that should be more stable with heavy quarks; completion of the table of positiveparity B_J mesons and study of their basic properties; production of Lambda_b\bar{Lambda}_b heavy baryon pairs, that, following weak decay, open vistas on the charmed baryon spectrum and new channels to study CP violation; confirmation or refutation of the deviation from pQCD of the pion transition form factor, by extending the Q^2 reach of current analysis; and possibly reaching the threshold for the production of triplycharmed baryons. If, in addition, the future colliders can be later upgraded to 12.5 GeV, then the possibility of copious production of B_c\bar{B}_c pairs opens, entailing new studies of CP violation and improved, independent tests of the CKM picture (through determination of V_{bc}), and of effective theories for heavy quarks.European Physical Journal A 10/2012; 49(1). DOI:10.1140/epja/i201313007x · 2.74 Impact Factor 
Article: Deconfinement and quarkgluon plasma
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ABSTRACT: The theory of confinement and deconfinement is discussed as based on the properties of the QCD vacuum. The latter are described by field correlators of colorelectric and colormagnetic fields in the vacuum, which can be calculated analytically and on the lattice. As a result one obtains a selfconsistent theory of the confined region in the (μ, T) plane with realistic hadron properties. At the boundary of the confining region, the colorelectric confining correlator vanishes, and the remaining correlators describe strong nonperturbative dynamics in the deconfined region with (weakly) bound states. Resulting equation of state for μ = 0, p(T), are in good agreement with lattice data. Phase transition occurs due to evaporation of a part of the colorelectric gluon condensate, and the resulting critical temperatures Tc(μ) for different nf are in good correspondence with available data.International Journal of Modern Physics E 01/2012; 18(03). DOI:10.1142/S0218301309012768 · 1.34 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We reanalyse the two and threepion mass distributions in the decays X(3872)>rho J/psi and X(3872)>omega J/psi and argue that the present data favour the 1++ assignment for the quantum numbers of the X.Physical review D: Particles and fields 11/2011; 85(1). DOI:10.1103/PhysRevD.85.011501 · 4.86 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the role played by the threebody DD̅ π dynamics on the nearthreshold resonance X(3872) charmonium state, which is assumed to be formed by nonperturbative DD̅ * dynamics. It is demonstrated that, as compared to the naive staticpions approximation, the imaginary parts that originate from the inclusion of dynamical pions reduce substantially the width from the DD̅ π intermediate state. In particular, for a resonance peaked at 0.5 MeV below the D0D̅ *0 threshold, this contribution to the width is reduced by about a factor of 2, and the effect of the pion dynamics on the width grows as long as the resonance is shifted towards the D0D̅ 0π0 threshold. Although the physical width of the X is dominated by inelastic channels, our finding should still be of importance for the X line shapes in the DD̅ π channel below DD̅ * threshold. For example, in the scattering length approximation, the imaginary part of the scattering length includes effects of all the pion dynamics and does not only stem from the D* width. Meanwhile, we find that another important quantity for the X phenomenology, the residue at the X pole, is weakly sensitive to dynamical pions. In particular, we find that the binding energy dependence of this quantity from the full calculation is close to that found from a model with pointlike DD̅ * interactions only, consistent with earlier claims. Coupledchannel effects (inclusion of the charged DD̅ * channel) turn out to have a moderate impact on the results.Physical review D: Particles and fields 10/2011; 84(7). DOI:10.1103/PhysRevD.84.074029 · 4.86 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: We investigate the role played by the threebody $D\bar{D}\pi$ dynamics on the nearthreshold resonance X(3872) charmonium state, which is assumed to be formed by nonperturbative $D\bar D^*$ dynamics. It is demonstrated that, as compared to the naive staticpions approximation, the imaginary parts that originate from the inclusion of dynamical pions reduce substantially the width from the $D\bar{D}\pi$ intermediate state. In particular, for a resonance peaked at 0.5 MeV below the $D^0\bar D^{*0}$ threshold, this contribution to the width is reduced by about a factor of 2, and the effect of the pion dynamics on the width grows as long as the resonance is shifted towards the $D^0\bar{D^0}\pi^0$ threshold. Although the physical width of the $X$ is dominated by inelastic channels, our finding should still be of importance for the $X$ line shapes in the $D\bar{D}\pi$ channel below $D{\bar D}^*$ threshold. For example, in the scattering length approximation, the imaginary part of the scattering length includes effects of all the pion dynamics and does not only stem from the $D^*$ width. Meanwhile, we find that another important quantity for the $X$ phenomenology, the residue at the $X$ pole, is weakly sensitive to dynamical pions. In particular, we find that the binding energy dependence of this quantity from the full calculation is close to that found from a model with pointlike $D\bar D^*$ interactions only, consistent with earlier claims. Coupledchannel effects (inclusion of the charged $D\bar{D}^*$ channel) turn out to have a moderate impact on the results. 
Article: Interplay of quark and meson degrees of freedom in a nearthreshold resonance: Multichannel case
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ABSTRACT: We investigate the interplay of quark and meson degrees of freedom in a physical state representing a nearthreshold resonance for the case of multiple continuum channels. The aim is to demonstrate the full complexity of possible nearthreshold phenomena. It turns out that those are especially rich, if both quark and meson dynamics generate simultaneously weakly coupled nearthreshold poles in the Smatrix. We study the properties of this scenario in detail, such as tmatrix and production amplitude zeros, as well as various effects of the continuum channels interplay.European Physical Journal A 08/2011; 47(8):110. DOI:10.1140/epja/i2011111019 · 2.74 Impact Factor  [Show abstract] [Hide abstract]
ABSTRACT: A possibility is suggested for the formation in the Universe of domains occupied by coherent‐like states of strongly correlated quark‐antiquark pairs. Only domains of the radius larger than 5 fm had a chance to survive over the entire history of the Universe, while the requirement of stability against the gravitational collapse restricts the maximum domain’s radius to 14 km. Within the Generalised Nambu–Jona‐Lasinio model, an exponential suppression with the domain’s volume is found for the overlap between the macroscopic ground‐state wavefunction of the quark‐antiquark pairs and the QCD vacuum. This finding supports, at the microscopic level, the above arguments in favour of the stability of the domains.05/2011; 1343(1):571573. DOI:10.1063/1.3575097 
Article: X(3872): Charmonium or molecule
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ABSTRACT: A theoretical analysis of the recent experimental data from the Belle and BABAR Collaborations on the charmonium state X(3872) is performed. The analysis takes into account the proximity of an Swave mesonic threshold and a possible presence of molecule component in the resonance wave function, finite width of the molecule constituents, and a possible interference in the final state. In particular, a modelindependent approach is formulated, based on the Flatte parametrisation of nearthreshold observables as well as on the Weinberg analysis of the nature of weakly bound systems generalised to the case of unstable constituents. Conclusion is made that the X(3872) is generated dynamically by a strong coupling of the bare chic1 charmonium to the DD* hadronic channel, with a large admixture of the DD* molecular component.01/2011; 1343. DOI:10.1063/1.3575040 
Article: Dark Quark Domains
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ABSTRACT: Formation of stable domains filled with strongly correlated coherent quark matter is discussed in general terms and is exemplified further in the framework of the Generalised NambuJonaLasinio model. It is argued that such domains, if exist in the Universe, appear dark to an external observer.JETP Letters 11/2010; 92(11). DOI:10.1134/S0021364010230013 · 1.36 Impact Factor 
Article: X(3872) as a D21 charmonium state
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ABSTRACT: The D21 charmonium assignment for the X(3872) meson is considered, as prompted by a recent result from the BABAR Collaboration, favoring 2+ quantum numbers for X. It is shown that established properties of X(3872) are in a drastic conflict with the D21 cc¯ assignment.Physical review D: Particles and fields 11/2010; 82(9). DOI:10.1103/PhysRevD.82.097502 · 4.86 Impact Factor
Publication Stats
1k  Citations  
229.82  Total Impact Points  
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Institutions

20122015

National Research Nuclear University MEPHI
Moskva, Moscow, Russia


19972013

Institute for Theoretical and Experimental Physics
Moskva, Moscow, Russia


2001

Instituto Superior de Contabilidade e Administração de Lisboa
Lisboa, Lisbon, Portugal
