V. Chobanova
A5054602025- Particle physics theoretical and experimental studies
- Quantum Chromodynamics and Particle Interactions
- High-Energy Particle Collisions Research
- Neutrino Physics Research
- Particle Accelerators and Free-Electron Lasers
- Computational Physics and Python Applications
- Black Holes and Theoretical Physics
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Nuclear physics research studies
- Stochastic processes and statistical mechanics
- International Science and Diplomacy
- Cosmology and Gravitation Theories
- Distributed and Parallel Computing Systems
- Cold Atom Physics and Bose-Einstein Condensates
- Markov Chains and Monte Carlo Methods
- Radiation Detection and Scintillator Technologies
- Advanced NMR Techniques and Applications
- advanced mathematical theories
- Astrophysics and Cosmic Phenomena
- Electron and X-Ray Spectroscopy Techniques
- Advanced Data Storage Technologies
Universidade da Coruña
2024-2025
Universitat Ramon Llull
2024-2025
Universidade de Santiago de Compostela
2017-2024
RWTH Aachen University
2023-2024
Instituto de Física Corpuscular
2023
Universitat de Barcelona
2023
Universitat de València
2023
Max Planck Society
2013-2018
Max Planck Institute for Physics
2013-2017
Max Planck Innovation
2014-2015
The cross section for ee+ e- → π+ π- J/ψ between 3.8 and 5.5 GeV is measured with a 967 fb(-1) data sample collected by the Belle detector at or near Υ(nS) (n = 1,2,…,5) resonances. Y(4260) state observed, its resonance parameters are determined. In addition, an excess of production around 4 observed. This feature can be described Breit-Wigner parametrization properties that consistent Y(4008) was previously reported Belle. study decays, structure observed in M(π(±)J/ψ) mass spectrum 5.2σ...
We report a measurement of the branching fraction ratios R(D(*)) Bbar -> D(*) tau- nubar_tau relative to D()* l- nubar_l (where l = e or mu) using full Belle data sample 772 x 10^6 BBbar pairs collected at Y(4S) resonance with detector KEKB asymmetric-energy e+e- collider. The measured values are R(D)= 0.375 +- 0.064(stat.) 0.026(syst.) and R(D*) 0.293 0.038(stat.) 0.015(syst.). analysis uses hadronic reconstruction tag-side B meson purely leptonic tau decays. results consistent earlier...
We report a measurement of the ratio ${\cal R}(D^*) = {\cal B}(\bar{B}^0 \rightarrow D^{*+} \tau^- \bar{\nu}_{\tau})/{\cal \ell^- \bar{\nu}_{\ell})$, where $\ell$ denotes an electron or muon. The results are based on data sample containing $772\times10^6$ $B\bar{B}$ pairs recorded at $\Upsilon(4S)$ resonance with Belle detector KEKB $e^+ e^-$ collider. select $B^0 \bar{B}^0$ by reconstructing both $B$ mesons in semileptonic decays to $D^{*\mp} \ell^{\pm}$. measure R}(D^*)= 0.302 \pm...
This paper reports world averages of measurements $b$-hadron, $c$-hadron, and $\tau$-lepton properties obtained by the Heavy Flavour Averaging Group using results available before April 2021. In rare cases, significant several months later are also used. For averaging, common input parameters used in various analyses adjusted (rescaled) to values, known correlations taken into account. The include branching fractions, lifetimes, neutral meson mixing parameters, CP violation semileptonic...
We present the results of an amplitude analysis anti-B0 -> J/psi K- pi+ decays. A new charged charmoniumlike state Zc(4200)+ decaying to is observed with a significance 6.2 sigma. The mass and width are 4196 +31-29 +17-13 MeV/c^2 370 +70-70 +70-132 MeV, respectively; preferred assignment quantum numbers J^P = 1^+. In addition, we find evidence for Zc(4430)+ pi+. based on 711 fb^-1 data sample collected by Belle detector at asymmetric-energy e+ e- collider KEKB.
We present a determination of the magnitude Cabibbo-Kobayashi-Maskawa matrix element $|V_{cb}|$ using decay $B\to D\ell\nu_\ell$ ($\ell=e,\mu$) based on 711 fb$^{-1}$ $e^+e^-\to \Upsilon(4S)$ data recorded by Belle detector and containing $772 \times 10^6$ $B\bar{B}$ pairs. One $B$ meson in event is fully reconstructed hadronic mode while other, signal side, partially from charged lepton either $D^+$ or $D^0$ total 23 modes. The isospin-averaged branching fraction found to be...
We report measurement of the cross section $e^+e^-\to \pi^+\pi^-\psi(2S)$ between 4.0 and $5.5 {\rm GeV}$, based on an analysis initial state radiation events in a $980 \rm fb^{-1}$ data sample recorded with Belle detector. The properties $Y(4360)$ $Y(4660)$ states are determined. Fitting mass spectrum $\pi^+\pi^-\psi(2S)$ two coherent Breit-Wigner functions, we find solutions identical width but different couplings to electron-positron pairs: $M_{Y(4360)} = (4347\pm 6\pm 3) MeV}/c^2$,...
We report on a search for heavy neutrinos in B-meson decays. The results are obtained using data sample that contains 772x10^6 BB-bar pairs collected at the Upsilon(4S) resonance with Belle detector KEKB asymmetric-energy e+e- collider. No signal is observed and upper limits set mixing of left-handed Standard Model mass range 0.5 - 5.0 GeV/c^2.
We report a search for the rare decays $B\ensuremath{\rightarrow}{h}^{(*)}\ensuremath{\nu}\overline{\ensuremath{\nu}}$, where ${h}^{(*)}$ stands ${K}^{+}$, ${K}_{S}^{0}$, ${K}^{*+}$, ${K}^{*0}$, ${\ensuremath{\pi}}^{+}$, ${\ensuremath{\pi}}^{0}$, ${\ensuremath{\rho}}^{+}$, ${\ensuremath{\rho}}^{0}$ and $\ensuremath{\phi}$. The results are obtained from $711\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample that contains $772\ifmmode\times\else\texttimes\fi{}{10}^{6}B\overline{B}$...
We present the first model-independent measurement of absolute branching fraction Λ(c)(+) → pK(-)π(+) decay using a data sample 978 fb(-1) collected with Belle detector at KEKB asymmetric-energy e(+)e(-) collider. The number baryons is determined by reconstructing recoiling D((*)-) pπ(+) system in events type pπ(+)Λ(c)(+). measured to be B(Λ(c)(+) pK(-)π(+)) = (6.84 ± 0.24(-0.27)(+0.21))%, where and second uncertainties are statistical systematic, respectively.
We report measurements of B→χ(c1)γK and χ(c2)γK decays using 772×10(6) BB[over ¯] events collected at the Υ(4S) resonance with Belle detector KEKB asymmetric-energy e(+)e(-) collider. Evidence a new in χ(c1)γ final state is found statistical significance 3.8σ. This has mass 3823.1±1.8(stat)±0.7(syst) MeV/c(2), value that consistent theoretical expectations for previously unseen 1(3)D(2) cc[over meson. find no other narrow set upper limits on branching fractions X(3872)→χ(c1)γ χ(c2)γ decays.
We report results of a study doubly charmed baryons and strange baryons. The analysis is performed using $980\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data sample collected with the Belle detector at KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. search for ${\mathrm{\ensuremath{\Xi}}}_{cc}^{+(+)}$ ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}({\ensuremath{\pi}}^{+})$...
We report the analysis of three-body e^{+}e^{-}→BB[over ¯]π^{±}, BB[over ¯]^{*}π^{±}, and B^{*}B[over ¯]^{*}π^{±} processes, including first observations Z_{b}^{±}(10610)→[BB[over ¯]^{*}+c.c.]^{±} Z_{b}^{±}(10650)→[B^{*}B[over ¯]^{*}]^{±} transitions that are found to dominate corresponding final states. measure Born cross sections for production σ(e^{+}e^{-}→[BB[over ¯]^{*}+c.c.]^{±}π^{∓})=[17.4±1.6(stat)±1.9(syst)] pb σ(e^{+}e^{-}→[B^{*}B[over ¯]^{*}]^{±}π^{∓})=[8.75±1.15(stat)±1.04(syst)]...
We report results on studies of the e+e- annihilation into three-body Y(nS)pi+pi- (n=1,2,3) final states including measurements cross sections and full amplitude analysis. The measured at sqrt(s)=10.865 GeV corrected for initial state radiation are sigma(e+e-=>Y(1S)pi+pi-)=(2.27+-0.12+-0.14) pb, sigma(e+e-=>Y(2S)pi+pi-)=(4.07+-0.16+-0.45) sigma(e+e-=>Y(3S)pi+pi-)=(1.46+-0.09+-0.16) pb. Amplitude analysis strongly favors I^G(J^P)=1^+(1^+) quantum-number assignments two bottomonium-like Zb+-...
We report measurements of the branching fractions and direct CP asymmetries (A_{CP}) for B->K pi, pi KK decays (but not pi^0 pi^0) based on final data sample 772x10^6 B B-bar pairs collected at Upsilon(4S) resonance with Belle detector KEKB asymmetric-energy e^+ e^- collider. set a 90% confidence-level upper limit K^+- K^-+ 2.0x10^{-7}; all other are observed ranging from 10^{-6} to 10^{-5}. In $B^0/B^0-bar -> K^+-\pi^-+ mode, we confirm Belle's previously reported large A_{CP} value -0.069...
A bstract We present measurements of absolute branching fractions hadronic and lep-tonic $ D_s^{+} decays to K − + π , {{\overline{K}}^0} ηπ μ ν τ report a search for the leptonic → e decays. The results are obtained from data sample 913 fb −1 collected at or near \varUpsilon (4 S ) (5 resonances with Belle detector KEKB asymmetric-energy collider. measured be \begin{array}{*{20}{c}} {\mathcal{B}\left( {D_s^{+}\ \to\ {K^{-}}{K^{+}}{\pi^{+}}} \right) = \left( {5.06\pm 0.15\pm 0.21}...
A new measurement of the branching fraction leptonic decay ${B}^{+}\ensuremath{\rightarrow}{\ensuremath{\tau}}^{+}\phantom{\rule{0}{0ex}}{\ensuremath{\nu}}_{\ensuremath{\tau}}$ confirms previous measurements and agrees with standard model predictions.
We report the first observation of Y(5S) -> Y(nS) pi0 decays. The neutral partner Zb+-(10610), Zb0(10610) decaying to Y(2,3S) pi0, is observed for time with a 6.5 sigma significance using Dalitz analysis results are obtained 121.4 fb^-1 data sample collected Belle detector at resonance KEKB asymmetric-energy e+e- collider.
Measurements of inclusive differential cross sections for charged pion and kaon production in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation have been carried out at a center-of-mass energy $\sqrt{s}=10.52\text{ }\text{ }\mathrm{GeV}$. The measurements were performed with the Belle detector KEKB collider using data sample containing $113\ifmmode\times\else\texttimes\fi{}{10}^{6}$ ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}q\overline{q}$ events, where $q={u,d,s,c}$. We present...
We report measurements of branching fractions $\tau$ lepton decays to final states with a $K^{0}_{S}$ meson using 669 fb$^{-1}$ data sample accumulated the Belle detector at KEKB asymmetric-energy $e^{+}e^{-}$ collider. The inclusive fraction is measured be $\mathcal{B}(\tau^{-} \to K^{0}_{S}\ X^{-} \nu_{\tau})=(9.15 \pm 0.01 0.15) \times 10^{-3}$, where $X^{-}$ can anything; exclusive are \pi^{-} K^{0}_{S} \nu_{\tau}) = (4.16 0.08) K^{-} (7.40 0.07 0.27) 10^{-4}$, \pi^{0} (1.93 0.02 0.07)...
We use 772$\times 10^6$ $B \bar{B}$ meson pairs collected at the $\Upsilon(4S)$ resonance with Belle detector to measure branching fraction for $\bar{B} \rightarrow X_s \gamma$. Our measurement uses a sum-of-exclusives approach in which 38 of hadronic final states strangeness equal $+1$, denoted by $X_s$, are reconstructed. The inclusive $M_{X_s}<$ 2.8 GeV/$c^2$, corresponds minimum photon energy 1.9 GeV, is measured be ${\cal B}(\bar{B} \gamma)=(3.51\pm0.17\pm0.33)\times10^{-4}$, where...
The dark photon ${A}^{\ensuremath{'}}$ and the Higgs boson ${h}^{\ensuremath{'}}$ are hypothetical constituents featured in a number of recently proposed sector models. Assuming prompt decays both particles, we search for their production so-called Higgstrahlung channel ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{A}^{\ensuremath{'}}{h}^{\ensuremath{'}}$, with ${h}^{\ensuremath{'}}\ensuremath{\rightarrow}{A}^{\ensuremath{'}}{A}^{\ensuremath{'}}$. We investigate ten exclusive final...