Olena Romanets
University of Groningen
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Featured researches published by Olena Romanets.
Physical Review D | 2013
C. Garcia-Recio; J. Nieves; Olena Romanets; L. L. Salcedo; L. Tolos
c and one c quarks). We analyze several possible sectors and, for the sector with zero net charm, we write down the most general Lagrangian consistent with SU(3) and heavy quark spin symmetry. We explicitly study theN andstates, which are produced from theS-wave interaction of pseudoscalar and vector mesons with 1/2 + and 3/2 + baryons within the charmless and strangeless hidden charm sector. We predict seven odd parityN-like and five �-like states with masses around 4GeV, most of them as bound states. These states form heavy-quark spin multiplets, which are almost degenerate in mass. The predicted new resonances definitely cannot be accommodated by quark models with three constituent quarks and they might be looked for in the forthcomingexperiment at the future FAIR facility.
Physical Review D | 2012
Olena Romanets; Laura Tolos; C. Garcia-Recio; J. Nieves; L. L. Salcedo; Rob Timmermans
We study charmed and strange baryon resonances that are generated dynamically by a unitary baryon-meson coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa chiral Lagrangian to SU(8) spin-flavor symmetry plus a suitable symmetry breaking. The model produces resonances with negative parity from s-wave interaction of pseudoscalar and vector mesons with 1/2(+) and 3/2(+) baryons. Resonances in all the isospin, spin, and strange sectors with one, two, and three charm units are studied. Our results are compared with experimental data from several facilities, such as the CLEO, Belle or BABAR collaborations, as well as with other theoretical models. Some of our dynamically-generated states can be readily assigned to resonances found experimentally, while others do not have a straightforward identification and require the compilation of more data and also a refinement of the model. In particular, we identify the Xi(c)(2790) and Xi(c)(2815) resonances as possible candidates for a heavy-quark spin symmetry doublet.
Physical Review D | 2013
C. Garcia-Recio; J. Nieves; Olena Romanets; L. L. Salcedo; L. Tolos
We thank E. Oset and E. Ruiz Arriola for discussions and Anton Poluektov for useful information on the LHCb experimental setup. This research was supported by DGI and FEDER funds, under Contracts No. FIS2011-28853-C02-02, No. FIS2011-24149, and No. FPA2010-16963 and the Spanish Consolider-Ingenio 2010 Program CPAN (CSD2007-00042), by Junta de Andalucia Grant No. FQM-225, by Generalitat Valenciana under Contract No. PROMETEO/2009/0090 and by the EU HadronPhysics2 project, Grant No. 227431. O. R. wishes to acknowledge support from the Rosalind Franklin Fellowship. L. T. acknowledges support from Ramon y Cajal Research Program, and from FP7-PEOPLE-2011-CIG under Contract No. PCIG09-GA-2011-291679.
Physical Review D | 2014
Laura Tolos; Olena Romanets
The interaction and propagation of anti-B mesons with light mesons, N and Delta baryons is studied within a unitarized approach based on effective models that are compatible with chiral and heavy-quark symmetries. We find several heavy-quark spin doublets in the open-bottom sectors, where anti-B and anti-B* mesons are present. In the meson sector we find several resonant states, among them, a B0 and a B1 with masses 5530 MeV and 5579 MeV as well as Bs0* and Bs1* narrow states at 5748 MeV and 5799 MeV, respectively. They form two doublets with no experimental identification yet, the first one being the bottom counterpart of the D0(2400) and D1(2430) states, and the second bottom doublet associated to the ubiquitous Ds0* (2317) and the Ds1 (2460). In the baryon sector, several Lambda_b and Sigma_b doublets are identified, among them the one given by the experimental Lambda_b(5910) and Lambda*_b(5921). Moreover, one of our states, the Sigma_b*(5904), turns out to be the bottom counterpart of the Sigma*(1670) and Sigma_c*(2549), which is a case for discovery. We finally analyze different transport coefficients for the anti-B meson in hot matter, such as formed in heavy-ion collisions at RHIC and LHC. For RHIC/LHC energies, the main contribution to the coefficients comes from the interaction of anti-B mesons with pions. However, we also include the effects of baryonic density which might be sizable at temperatures T < 100 MeV, as the chemical potential is expected to increase in the last stages of the expansion. We conclude that although the relaxation time decreases with larger baryonic densities, the anti-B meson does not thermalize at RHIC/LHC energies, representing an ideal probe for the initial bottom distribution.
Nuclear Physics | 2013
Olena Romanets; Laura Tolos; C. Garcia-Recio; J. Nieves; L. L. Salcedo; Robertus Timmermans
Abstract We study charmed and strange odd-parity baryon resonances that are generated dynamically by a unitary baryon–meson coupled-channels model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU ( 3 ) Weinberg–Tomozawa chiral Lagrangian to SU ( 8 ) spin-flavor symmetry plus a suitable symmetry breaking. The model generates resonances with negative parity from the s-wave interaction of pseudoscalar and vector mesons with 1 / 2 + and 3 / 2 + baryons in all the isospin, spin, and strange sectors with one, two, and three charm units. Some of our results can be identified with experimental data from several facilities, such as the CLEO, Belle, or BaBar Collaborations, as well as with other theoretical models, whereas others do not have a straightforward identification and require the compilation of more data and also a refinement of the model.
arXiv: Nuclear Theory | 2016
Laura Tolos; C. Garcia-Recio; Carlos Hidalgo-Duque; J. Nieves; Olena Romanets; L. L. Salcedo; Juan M. Torres-Rincon
We study the behavior of dynamically-generated baryon resonances with heavy- quark content within a unitarized coupled-channel theory in matter that fulfills heavy-quark spin symmetry constraints. We analyze the implications for the formation of charmed mesic nuclei and the propagation of heavy mesons in heavy-ion collisions from RHIC to FAIR.
arXiv: Nuclear Theory | 2016
Juan M. Torres-Rincon; L. M. Abreu; Daniel Cabrera; Olena Romanets; Laura Tolos
We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker-Planck reduction of the Boltzmann equation.
arXiv: Nuclear Theory | 2014
Laura Tolos; Daniel Cabrera; C. Garcia-Recio; Raquel Molina; J. Nieves; E. Oset; A. Ramos; Olena Romanets; L. L. Salcedo; Juan M. Torres-Rincon
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.
arXiv: High Energy Physics - Phenomenology | 2014
Olena Romanets; C. Garcia-Recio; L. L. Salcedo; J. Nieves; Laura Tolos
We study N and Δ hidden-charm baryon resonances that are generated dynamically from the s-wave interaction of pseudoscalar and vector mesons with 1/2+ and 3/2+ baryons. We use a unitary coupled-channels model that fulfills heavy-quark spin symmetry and respects spin-flavor symmetry in the light sector. We predict seven N-like and five Δ-like states with masses around 4 GeV, most of them as bound states. Some of these states form heavy-quark spin multiplets, which are almost degenerate in mass.
arXiv: High Energy Physics - Phenomenology | 2014
Olena Romanets
De studie van zware hadronen is een belangrijk onderwerp in de deeltjesfysica. In tegenstelling tot deeltjes die opgebouwd zijn uit lichte quarks,zijn toestanden met zware quarks (bijvoorbeeld charm of bottom quarks) moeilijk te beschrijven, omdat er geen goed model is. De ontwikkeling van nieuwe experimentele technieken maakt het echter mogelijk om nieuwe toestanden met zware quarks te observeren. Tegenwoordig is het een uitdaging om de aard van deze nieuwe deeltjes te interpreteren. Hadronresonanties, deeltjes die kunnen vervallen, kunnen worden beschreven als toestanden bestaand uit quarks en/of als toestanden bestaand uit hadronen, de zogenaamde moleculaire toestanden. Olena Romanets bestudeert in haar proefschrift baryonresonanties met zware quarks, moleculaire toestanden die dynamisch worden gegenereerd uit mesonen en baryonen. Hiervoor gebruikt ze een model dat twee belangrijke symmetrieen van de sterke interactie behoudt, de chirale symmetrie en de zware-quark spinsymmetrie. Ze vond een aantal charm en strange baryonresonanties die vergeleken kunnen worden met experimentele toestanden en deed voorspellingen voor andere toestanden met totale charm nummer 1, 2 en 3. Bovendien verkreeg ze met het model twee bottomtoestanden met massa’s 5912 en 5920 MeV. Deze toestanden zijn vorig jaar gevonden door de LHCb collaboratie. ‘We hebben ook baryonresonanties met verborgen charm geanalyseerd en we voorspellen een aantal toestanden met massa’s rond de 4 GeV, de meesten als een gebonden toestand. Al onze resultaten zullen binnenkort worden getest in het PANDA experiment bij de FAIR faciliteit in Duitsland.’