Dmitri Melikhov

Current Organizations / Institutes

The organizations/institutes from the scholar's latest article

Previous Organizations / Institutes

The organizations / institutes from the scholar's other articles in the past ten years

Research Subjects

High Energy Physics

Research Interests

Dmitri Melikhov has a total of 192 co-authors. Here are the top co-authors by number of shared publications:

Silvano Simula
INFN, Sezione di Roma Tre
78 shared publications
Wolfgang Lucha
Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna, Austria
78 shared publications
Wolfgang Lucha
46 shared publications
Hagop Sazdjian
Université Paris-Saclay
35 shared publications
D V Skobeltsyn
Institute for High Energy Physics Austrian Academy of Sciences Nikolsdorfergasse 18 A-1050 Vienna Austria
12 shared publications
Irina Balakireva
Saha Institute of Nuclear physics
7 shared publications

Latest Publications

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- 8 December 2025
- Published by Springer Nature in The European Physical Journal C
Factorization of multiparticle contributions to amplitudes of B-meson weak decays
by Dmitri Melikhov
We show that multiparticle contributions to amplitudes of weak decays of the generic topology (heavy quark hits some intermediate point of the propagator line joining the end-points from which momenta q and $$q'$$ $q^{'}$ are emitted) is given in the heavy quark limit and at the leading order in $$\alpha _s$$ $α_{s}$ by the convolution of (i) hard kernel composed of highly virtual propagators of light degrees of freedom and (ii) the B -meson multiparticle wave function, $$\langle 0|\phi (x)\phi (x_1)\cdots \phi (x_n)\phi _b(0)\phi (x'_{n'})\cdots \phi (x'_1)\phi (x')|B(p)\rangle $$ $⟨ 0 | ϕ (x) ϕ (x_{1}) \dots ϕ (x_{n}) ϕ_{b} (0) ϕ (x_{n^{'}}^{'}) \dots ϕ (x_{1}^{'}) ϕ (x^{'}) | B (p) ⟩$ , in a double-collinear light-cone configuration: the coordinates $$x,x_1,\ldots ,x_n$$ $x, x_{1}, \dots, x_{n}$ are ordered and aligned along the light-like 4-vector $$a_\mu $$ $a_{μ}$ , $$a^2=0$$ $a^{2} = 0$ , $$q_\mu \propto a_\mu $$ $q_{μ} \propto a_{μ}$ , while the coordinates $$x',x_1',\ldots ,x'_{n'}$$ $x^{'}, x_{1}^{'}, \dots, x_{n^{'}}^{'}$ are ordered and aligned along the light-like 4-vector $$a'_\mu $$ $a_{μ}^{'}$ , $$a'^2=0$$ $a^{' 2} = 0$ , $$q'_\mu \propto a'_\mu $$ $q_{μ}^{'} \propto a_{μ}^{'}$ , $$a'a\ne 0$$ $a^{'} a \neq 0$ . Corrections to this factorization formula are suppressed by powers of $$\Lambda _\textrm{QCD}/M_B$$ $Λ_{QCD} / M_{B}$ .
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- 8 December 2025
- Published by Springer Nature in The European Physical Journal C
Open Access
Factorization of multiparticle contributions to amplitudes of B-meson weak decays
by Dmitri Melikhov
We show that multiparticle contributions to amplitudes of weak decays of the generic topology (heavy quark hits some intermediate point of the propagator line joining the end-points from which momenta q and $$q'$$ $q^{'}$ are emitted) is given in the heavy quark limit and at the leading order in $$\alpha _s$$ $α_{s}$ by the convolution of (i) hard kernel composed of highly virtual propagators of light degrees of freedom and (ii) the B -meson multiparticle wave function, $$\langle 0|\phi (x)\phi (x_1)\cdots \phi (x_n)\phi _b(0)\phi (x'_{n'})\cdots \phi (x'_1)\phi (x')|B(p)\rangle $$ $⟨ 0 | ϕ (x) ϕ (x_{1}) \dots ϕ (x_{n}) ϕ_{b} (0) ϕ (x_{n^{'}}^{'}) \dots ϕ (x_{1}^{'}) ϕ (x^{'}) | B (p) ⟩$ , in a double-collinear light-cone configuration: the coordinates $$x,x_1,\ldots ,x_n$$ $x, x_{1}, \dots, x_{n}$ are ordered and aligned along the light-like 4-vector $$a_\mu $$ $a_{μ}$ , $$a^2=0$$ $a^{2} = 0$ , $$q_\mu \propto a_\mu $$ $q_{μ} \propto a_{μ}$ , while the coordinates $$x',x_1',\ldots ,x'_{n'}$$ $x^{'}, x_{1}^{'}, \dots, x_{n^{'}}^{'}$ are ordered and aligned along the light-like 4-vector $$a'_\mu $$ $a_{μ}^{'}$ , $$a'^2=0$$ $a^{' 2} = 0$ , $$q'_\mu \propto a'_\mu $$ $q_{μ}^{'} \propto a_{μ}^{'}$ , $$a'a\ne 0$$ $a^{'} a \neq 0$ . Corrections to this factorization formula are suppressed by powers of $$\Lambda _\textrm{QCD}/M_B$$ $Λ_{QCD} / M_{B}$ .
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- 1 December 2025
- Published by Allerton Press in Moscow University Physics Bulletin
Analysis of $\boldsymbol{B\to KM_{X}}$ and $\boldsymbol{B\to K^{*}M_{X}}$ Decays in Scalar- and Vector-Mediator Dark-Matter Scenarios
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
The surprising excess of missing-energy events far beyond all standard-model expectations in the weak decays of the charged ground-state $$B^{+}$$ meson in
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- 1 December 2025
- Published by Allerton Press in Moscow University Physics Bulletin
Analysis of $\boldsymbol{B\to KM_{X}}$ and $\boldsymbol{B\to K^{*}M_{X}}$ Decays in Scalar- and Vector-Mediator Dark-Matter Scenarios
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
The surprising excess of missing-energy events far beyond all standard-model expectations in the weak decays of the charged ground-state $$B^{+}$$ meson in
Open Access
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Cited by 6
- 21 November 2025
- Published by MDPI AG in Universe
Scrutinizing Dark-Matter Scenarios with B → (K, $K^{*}$ ) $\bar{ν}$ ν Decays
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
Conceivable explanations of Belle-II measurements of a (surprising) excess of missing energy decays of the B meson to the K meson not covered by standard model neutrino–antineutrino pairs might be offered by additional contributions of dark matter fermion–antifermion pairs. Assuming the excessive missing-energy events to be mediated by a (generic) scalar or vector boson, a simultaneous inspection of both the missing energy B decays into a pseudoscalar K meson or a vector $K^{*}$ meson enables to gain information on the nature of any boson relating the standard-model and dark-matter sectors, irrespective of (unknown) dark-sector details. Upon availability of indispensable experimental data, most prominent among such insights might be the identification of the mediator spin from the differential B-meson decay widths.
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- 21 November 2025
- Published by MDPI AG in Universe
Open Access
Scrutinizing Dark-Matter Scenarios with B → (K, $K^{*}$ ) $\bar{ν}$ ν Decays
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
Conceivable explanations of Belle-II measurements of a (surprising) excess of missing energy decays of the B meson to the K meson not covered by standard model neutrino–antineutrino pairs might be offered by additional contributions of dark matter fermion–antifermion pairs. Assuming the excessive missing-energy events to be mediated by a (generic) scalar or vector boson, a simultaneous inspection of both the missing energy B decays into a pseudoscalar K meson or a vector $K^{*}$ meson enables to gain information on the nature of any boson relating the standard-model and dark-matter sectors, irrespective of (unknown) dark-sector details. Upon availability of indispensable experimental data, most prominent among such insights might be the identification of the mediator spin from the differential B-meson decay widths.
Cited by 6
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Cited by 21
- 30 April 2025
- Published by American Physical Society (APS) in Physical Review D
Analysis of $q_{rec}^{2}$ -distribution for $B \to K M_{X}$ and $B \to K^{*} M_{X}$ decays in a scalar-mediator dark-matter scenario
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
We demonstrate that the scalar-mediator dark-matter scenario is consistent with the experimental data on the decay B → K M X and provides a good description of the shape of the observed excess. Within this scenario, the interaction with dark-matter particles leads to approximately the same excess in Γ ( B → K * M X ) and Γ ( B → K M X ) compared to the Standard Model; also the differential distributions of the excess events are similar in shape in the variable q rec 2 measured by experiment. Published by the American Physical Society 2025
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- 30 April 2025
- Published by American Physical Society (APS) in Physical Review D
Open Access
Analysis of $q_{rec}^{2}$ -distribution for $B \to K M_{X}$ and $B \to K^{*} M_{X}$ decays in a scalar-mediator dark-matter scenario
by Alexander Berezhnoy, Wolfgang Lucha, Dmitri Melikhov
We demonstrate that the scalar-mediator dark-matter scenario is consistent with the experimental data on the decay B → K M X and provides a good description of the shape of the observed excess. Within this scenario, the interaction with dark-matter particles leads to approximately the same excess in Γ ( B → K * M X ) and Γ ( B → K M X ) compared to the Standard Model; also the differential distributions of the excess events are similar in shape in the variable q rec 2 measured by experiment. Published by the American Physical Society 2025
Cited by 21
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- 26 November 2024
- Published by American Physical Society (APS) in Physical Review D
Constraining $λ_{B_{s}}$ by $B_{s} \to γ^{*}$ and $B_{s} \to ϕ$ form factors
by Mikhail A. Ivanov, Dmitri Melikhov, Silvano Simula
We calculate the form factors F V ( q 2 , q ′ 2 ) and F T V ( q 2 , q ′ 2 ) describing the B s → γ * transition induced by the vector and tensor weak currents in a broad range of values of q 2 and q ′ 2 far below the quark thresholds in both q 2 and q ′ 2 channels. These form factors are calculated via the distribution amplitudes of the B s -meson. We then interpolate the obtained results by a formula that contains pole at q ′ 2 = M ϕ 2 and extract the residue which gives the B s → ϕ transition form factors V ( q 2 ) and T 1 ( q 2 ) . In this way we obtain theoretical predictions for these form factors without invoking quark-hadron duality and QCD sum rules. Furthermore, we calculate the relationship between V ( 0 ) and T 1 ( 0 ) and the parameter λ B s ( μ ) , the inverse moment of the B s -meson distribution amplitude. Using the available predictions for V ( 0 ) and T 1 ( 0 ) coming from approaches not referring to the B s -meson distribution amplitudes, we obtain the estimate λ B s ( μ ≃ m b ) = ( 0.62 ± 0.10 ) GeV . Published by the American Physical Society 2024
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- 26 November 2024
- Published by American Physical Society (APS) in Physical Review D
Open Access
Constraining $λ_{B_{s}}$ by $B_{s} \to γ^{*}$ and $B_{s} \to ϕ$ form factors
by Mikhail A. Ivanov, Dmitri Melikhov, Silvano Simula
We calculate the form factors F V ( q 2 , q ′ 2 ) and F T V ( q 2 , q ′ 2 ) describing the B s → γ * transition induced by the vector and tensor weak currents in a broad range of values of q 2 and q ′ 2 far below the quark thresholds in both q 2 and q ′ 2 channels. These form factors are calculated via the distribution amplitudes of the B s -meson. We then interpolate the obtained results by a formula that contains pole at q ′ 2 = M ϕ 2 and extract the residue which gives the B s → ϕ transition form factors V ( q 2 ) and T 1 ( q 2 ) . In this way we obtain theoretical predictions for these form factors without invoking quark-hadron duality and QCD sum rules. Furthermore, we calculate the relationship between V ( 0 ) and T 1 ( 0 ) and the parameter λ B s ( μ ) , the inverse moment of the B s -meson distribution amplitude. Using the available predictions for V ( 0 ) and T 1 ( 0 ) coming from approaches not referring to the B s -meson distribution amplitudes, we obtain the estimate λ B s ( μ ≃ m b ) = ( 0.62 ± 0.10 ) GeV . Published by the American Physical Society 2024
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Cited by 5
- 10 June 2024
- Published by American Physical Society (APS) in Physical Review D
Nonfactorizable charming-loop contribution to FCNC $B_{s} \to γ l^{+} l^{-}$ decay
by Ilia Belov, Alexander Berezhnoy, Dmitri Melikhov
We present the first theoretical calculation of nonfactorizable charm-quark loop contributions to the $B_{s} \to γ l^{+} l^{-}$ amplitude. We calculate the relevant form factors, $H_{A, V}^{NF} (k^{' 2}, k^{2})$ , and provide convenient parametrizations of our results in the form of fit functions of two variables, $k^{' 2}$ and $k^{2}$ , applicable in the region below hadron resonances, $k^{' 2} < M_{J / ψ}^{2}$ and $k^{2} < M_{ϕ}^{2}$ . We report that factorizable and nonfactorizable charm contributions to the $B_{s} \to γ l^{+} l^{-}$ amplitude have opposite signs. To compare the charm and the top contributions, it is convenient to express nonfactorizable charming loop contribution as a nonuniversal (i.e., dependent on the reaction) $q^{2}$ -dependent correction $Δ^{NF} C_{7} (q^{2})$ to the Wilson coefficient $C_{7}$ . For the $B_{s} \to γ l^{+} l^{-}$ amplitude, the correction is found to be positive, $Δ^{NF} C_{7} (q^{2}) / C_{7} > 0$ .
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- 10 June 2024
- Published by American Physical Society (APS) in Physical Review D
Open Access
Nonfactorizable charming-loop contribution to FCNC $B_{s} \to γ l^{+} l^{-}$ decay
by Ilia Belov, Alexander Berezhnoy, Dmitri Melikhov
We present the first theoretical calculation of nonfactorizable charm-quark loop contributions to the $B_{s} \to γ l^{+} l^{-}$ amplitude. We calculate the relevant form factors, $H_{A, V}^{NF} (k^{' 2}, k^{2})$ , and provide convenient parametrizations of our results in the form of fit functions of two variables, $k^{' 2}$ and $k^{2}$ , applicable in the region below hadron resonances, $k^{' 2} < M_{J / ψ}^{2}$ and $k^{2} < M_{ϕ}^{2}$ . We report that factorizable and nonfactorizable charm contributions to the $B_{s} \to γ l^{+} l^{-}$ amplitude have opposite signs. To compare the charm and the top contributions, it is convenient to express nonfactorizable charming loop contribution as a nonuniversal (i.e., dependent on the reaction) $q^{2}$ -dependent correction $Δ^{NF} C_{7} (q^{2})$ to the Wilson coefficient $C_{7}$ . For the $B_{s} \to γ l^{+} l^{-}$ amplitude, the correction is found to be positive, $Δ^{NF} C_{7} (q^{2}) / C_{7} > 0$ .
Cited by 5
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Cited by 53
- 1 January 2024
- Published by IOP Publishing in Europhysics Letters
vs. as a probe of a scalar mediator dark-matter scenario
by Alexander Berezhnoy, Dmitri Melikhov
Recently, Belle II reported the observation of the decay , where M _X is the missing mass, with the branching ratio much exceeding which is the only Standard Model (SM) process contributing to this reaction. If confirmed, this might be an indication of new non-SM particles produced in this decay. One of the possible explanations of the observed effect could be light dark-matter (DM) particles produced via a scalar mediator field. We give simple arguments, that a combined analysis of the and reactions would be a clean probe of the scalar mediator scenario: i) making use of an observed value and ii) assuming that the effect is due to the light dark-matter coupling to the top quark via a scalar mediator field, one finds an upper limit . Within the discussed scenario, this upper limit does not depend on the mass of the scalar mediator nor on the specific details of the unobserved dark-matter particles in the final state.
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- 1 January 2024
- Published by IOP Publishing in Europhysics Letters
vs. as a probe of a scalar mediator dark-matter scenario
by Alexander Berezhnoy, Dmitri Melikhov
Recently, Belle II reported the observation of the decay , where M _X is the missing mass, with the branching ratio much exceeding which is the only Standard Model (SM) process contributing to this reaction. If confirmed, this might be an indication of new non-SM particles produced in this decay. One of the possible explanations of the observed effect could be light dark-matter (DM) particles produced via a scalar mediator field. We give simple arguments, that a combined analysis of the and reactions would be a clean probe of the scalar mediator scenario: i) making use of an observed value and ii) assuming that the effect is due to the light dark-matter coupling to the top quark via a scalar mediator field, one finds an upper limit . Within the discussed scenario, this upper limit does not depend on the mass of the scalar mediator nor on the specific details of the unobserved dark-matter particles in the final state.
Cited by 53
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Cited by 9
- 15 November 2023
- Published by American Physical Society (APS) in Physical Review D
Charming-loop contribution to $B_{s} \to γ γ$ decay
by Ilia Belov, Alexander Berezhnoy, Dmitri Melikhov
We present a detailed theoretical study of nonfactorizable contributions of the charm-quark loop to the amplitude of the $B_{s} \to γ γ$ decay. This contribution involves the $B$ -meson three-particle Bethe-Salpeter amplitude, $⟨ 0 | \bar{s} (y) G_{μ ν} (x) b (0) | {\bar{B}}_{s} (p) ⟩$ , for which we take into account constraints from analyticity and continuity. The charming-loop contribution of interest may be described as a correction to the Wilson coefficient $C_{7 γ}$ , $C_{7 γ} \to C_{7 γ} (1 + δ C_{7 γ})$ . We calculate an explicit dependence of $δ C_{7 γ}$ on the parameter $λ_{B_{s}}$ . Taking into account all theoretical uncertainties, $δ C_{7 γ}$ may be predicted with better than 10% accuracy for any given value of $λ_{B_{s}}$ . For our benchmark point $λ_{B_{s}} = 0.45 GeV$ , we obtain $δ C_{7 γ} = 0.045 \pm 0.004$ . Presently, $λ_{B_{s}}$ is not known with high accuracy, but its value is expected to lie in the range $0.3 \leq λ_{B_{s}} (GeV) \leq 0.6$ . The corresponding range of $δ C_{7 γ}$ is found to be $0.02 \leq δ C_{7 γ} \leq 0.1$ . One therefore expects the correction given by charming loops at the level of at least a few percent.
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- 15 November 2023
- Published by American Physical Society (APS) in Physical Review D
Open Access
Charming-loop contribution to $B_{s} \to γ γ$ decay
by Ilia Belov, Alexander Berezhnoy, Dmitri Melikhov
We present a detailed theoretical study of nonfactorizable contributions of the charm-quark loop to the amplitude of the $B_{s} \to γ γ$ decay. This contribution involves the $B$ -meson three-particle Bethe-Salpeter amplitude, $⟨ 0 | \bar{s} (y) G_{μ ν} (x) b (0) | {\bar{B}}_{s} (p) ⟩$ , for which we take into account constraints from analyticity and continuity. The charming-loop contribution of interest may be described as a correction to the Wilson coefficient $C_{7 γ}$ , $C_{7 γ} \to C_{7 γ} (1 + δ C_{7 γ})$ . We calculate an explicit dependence of $δ C_{7 γ}$ on the parameter $λ_{B_{s}}$ . Taking into account all theoretical uncertainties, $δ C_{7 γ}$ may be predicted with better than 10% accuracy for any given value of $λ_{B_{s}}$ . For our benchmark point $λ_{B_{s}} = 0.45 GeV$ , we obtain $δ C_{7 γ} = 0.045 \pm 0.004$ . Presently, $λ_{B_{s}}$ is not known with high accuracy, but its value is expected to lie in the range $0.3 \leq λ_{B_{s}} (GeV) \leq 0.6$ . The corresponding range of $δ C_{7 γ}$ is found to be $0.02 \leq δ C_{7 γ} \leq 0.1$ . One therefore expects the correction given by charming loops at the level of at least a few percent.
Cited by 9
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Cited by 13
- 7 August 2023
- Published by American Physical Society (APS) in Physical Review D
Three-particle distribution in the $B$ meson and charm-quark loops in FCNC $B$ decays
by Dmitri Melikhov
We discuss a nonfactorizable (NF) contribution of a charm loop to the FCNC $B$ -decay amplitude given through the three-particle Bethe-Salpeter amplitude (3BS) of the $B$ -meson. This 3BS contains one heavy-quark field and two light fields (a light quark and a gluon). Our discussion is aimed at clarifying properties of the $B$ -meson 3BS necessary to describe properly charm-loop contributions to the amplitudes of FCNC $B$ -decays. We demonstrate that the dominant contribution of nonfactorizable charm to FCNC $B$ -decay amplitude is given in the heavy-quark limit by a convolution of some hard kernel and the $B$ -meson 3BS in a “double-collinear” light cone (LC) configuration: one of the light degrees of freedom $ϕ (x)$ , $x^{2} = 0$ , lies on the ( $+$ )-direction of the LC, whereas another light degree of freedom $ϕ^{'} (x^{'})$ , $x^{' 2} = 0$ lies along the ( $-$ )-direction. We show the emergence of new constraints on the distribution amplitudes which parametrize the 3BS in this double-collinear configuration.
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- 7 August 2023
- Published by American Physical Society (APS) in Physical Review D
Open Access
Three-particle distribution in the $B$ meson and charm-quark loops in FCNC $B$ decays
by Dmitri Melikhov
We discuss a nonfactorizable (NF) contribution of a charm loop to the FCNC $B$ -decay amplitude given through the three-particle Bethe-Salpeter amplitude (3BS) of the $B$ -meson. This 3BS contains one heavy-quark field and two light fields (a light quark and a gluon). Our discussion is aimed at clarifying properties of the $B$ -meson 3BS necessary to describe properly charm-loop contributions to the amplitudes of FCNC $B$ -decays. We demonstrate that the dominant contribution of nonfactorizable charm to FCNC $B$ -decay amplitude is given in the heavy-quark limit by a convolution of some hard kernel and the $B$ -meson 3BS in a “double-collinear” light cone (LC) configuration: one of the light degrees of freedom $ϕ (x)$ , $x^{2} = 0$ , lies on the ( $+$ )-direction of the LC, whereas another light degree of freedom $ϕ^{'} (x^{'})$ , $x^{' 2} = 0$ lies along the ( $-$ )-direction. We show the emergence of new constraints on the distribution amplitudes which parametrize the 3BS in this double-collinear configuration.
Cited by 13
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Cited by 1
- 22 December 2022
- Published by EDP Sciences in EPJ Web of Conferences
Zooming in on Multiquark Hadrons within QCD Sum-Rule Approaches
by Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian
Aiming at self-consistent descriptions of multiquark hadrons (such as tetraquarks, pentaquarks, hexaquarks) by means of QCD sum rules, we note that the totality of contributions to two-point or three-point correlation functions that involve, respectively, either two or just a single operator capable of interpolating the particular multiquark under study can be straightforwardly disentangled into two disjoint classes defined by unambiguously identifiable members. The first is formed by so-called multiquark-phile contributions which indeed might support multiquarks. In the case of flavour-exotic tetraquarks, by definition composed of four (anti–) quarks of mutually different flavours, a tetraquark-phile contribution has to exhibit two or more gluon exchanges of appropriate topology. The second consists of contributions evidently not bearing any relation to multiquarks; these must be discarded when studying multiquarks by QCD sum rules. The first class only should enter the “multiquark-adequate” QCD sum rules for exotic hadrons.
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- 22 December 2022
- Published by EDP Sciences in EPJ Web of Conferences
Open Access
Zooming in on Multiquark Hadrons within QCD Sum-Rule Approaches
by Wolfgang Lucha, Dmitri Melikhov, Hagop Sazdjian
Aiming at self-consistent descriptions of multiquark hadrons (such as tetraquarks, pentaquarks, hexaquarks) by means of QCD sum rules, we note that the totality of contributions to two-point or three-point correlation functions that involve, respectively, either two or just a single operator capable of interpolating the particular multiquark under study can be straightforwardly disentangled into two disjoint classes defined by unambiguously identifiable members. The first is formed by so-called multiquark-phile contributions which indeed might support multiquarks. In the case of flavour-exotic tetraquarks, by definition composed of four (anti–) quarks of mutually different flavours, a tetraquark-phile contribution has to exhibit two or more gluon exchanges of appropriate topology. The second consists of contributions evidently not bearing any relation to multiquarks; these must be discarded when studying multiquarks by QCD sum rules. The first class only should enter the “multiquark-adequate” QCD sum rules for exotic hadrons.
Cited by 1

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