arXiv subjects

H. Sundu

Publications and source records attributed to H. Sundu.

At least 127 records · Page 7Linked to original sources

arXiv2017

Scalar and vector self-energies of heavy baryons in nuclear medium

The in-medium sum rules are employed to calculate the shifts in the mass and residue as well as the scalar and vector self-energies of the heavy $Λ_Q, Σ_Q$ and $Ξ_Q$ baryons, with Q being $b$ or $c$ quark. The maximum shift in mass due to nuclear matter belongs to the $Σ_c$ baryon and it is found to be $Δm_{Σ_{c}}=-936 ~ MeV$. In the case of residue, it is obtained that the residue of $Σ_b$ baryon is maximally affected by the nuclear medium with the shift $Δλ_{Σ_b} = -0.014 ~ GeV^3 $. The scalar and vector self-energies are found to be $Σ^{S}_{Λ_b} = 653 ~ MeV$, $Σ^{S}_{Σ_b} = -614 ~ MeV $, $Σ^{S}_{Ξ_b} = -17 ~ MeV $, $Σ^{S}_{Λ_c} = 272 ~ MeV $, $Σ^{S}_{Σ_c} = -936 ~ MeV $, $Σ^{S}_{Ξ_c} = -5 ~ MeV $ and $Σ^ν_{Λ_b} = 436 \pm 148 ~ MeV $, $Σ^ν_{Σ_b} = 382 \pm 129 ~MeV $, $Σ^ν_{Ξ_b} =15 \pm 5 ~ MeV$, $Σ^ν_{Λ_c} = 151 \pm 45 ~ MeV $, $Σ^ν_{Σ_c} = 486 \pm 144 ~ MeV $ and $Σ^ν_{Ξ_c} = 1.391 \pm 0.529 ~ MeV $.

hep-ph↗

arXiv2017

Radial Excitations of the Decuplet Baryons

The ground and first excited states of the decuplet baryons are studied using the two-point QCD sum rule approach. The mass and residue of these states are computed and compared with the existing experimental data and other theoretical predictions. The results for the masses of the ground state particles as well as the excited $ Δ$ and $ Σ^{*} $ states are in good consistency with experimental data. Our results on the excited $ Ξ^{*} $ and $ Ω^{-} $ states reveal that the experimentally poorly known $ Ξ(1950) $ and $ Ω^{-}(2250) $ can be assigned as the first excited states in $ Ξ^{*} $ and $ Ω^{-} $ channels, respectively.

hep-ph↗

arXiv2017

Application of the QCD light cone sum rule to tetraquarks: the strong vertices $X_bX_bρ$ and $X_cX_cρ$

The full version of QCD light-cone sum rule method is applied to tetraquarks containing a single heavy $b$ or $c$ quark. To this end, investigations of the strong vertices $X_{b}X_{b}ρ$ and $X_{c}X_{c}ρ$ are performed, where $X_b=[su][\bar b\bar d]$ and $X_c=[su][\bar c\bar d]$ are the exotic states built of four quarks of different flavors. The strong coupling constants $G_{X_{b}X_{b}ρ}$ and $G_{X_{c}X_{c}ρ}$ corresponding to these vertices are found using the $ρ$-meson leading and higher-twist distribution amplitudes. In the calculations $X_{b}$ and $X_{c}$ are treated as scalar bound states of a diquark and antidiquark.

hep-ph↗

arXiv2017

Open charm-bottom scalar tetraquarks and their strong decays

The mass and meson-current coupling of the diquark-antidiquark states with the quantum numbers $J^{P}=0^{+}$ and quark contents $Z_{q}=[cq][\bar {b} \bar q ]$ and $Z_{s}=[cs][\bar {b} \bar s]$ are calculated using two-point QCD sum rule approach. In calculations the quark, gluon and mixing condensates up to eight dimensions are taken into account. The parameters of the scalar tetraquarks extracted from this analysis are employed to explore the strong vertices $Z_q B_c π$, $Z_q B_c η$ and $Z_s B_c η$ and compute the couplings $g_{Z_qB_c π}$, $g_{Z_qB_c η}$ and $g_{Z_sB_c η}$. The strong couplings are obtained within the soft-meson approximation of QCD light-cone sum rule method: they form, alongside with other parameters, the basis for evaluating the widths of $Z_q \to B_c π$, $% Z_q \to B_c η$ and $Z_s \to B_c η$ decays. Obtained in this work results for the mass of the tetraquarks $Z_{q}$ and $Z_{s}$ are compared with available predictions presented in the literature.

hep-ph↗

arXiv2017

Resonance $X(5568)$ as an exotic axial-vector state

The mass and meson-current coupling constant of the resonance $X(5568)$, as well as the width of the decay $X(5568)\to B_s^{\ast}π$ are calculated by modeling the exotic $X(5568)$ resonance as a diquark-antidiquark state $% X_b=[su][bd]$ with quantum numbers $J^{P}=1^{+}$. The calculations are made employing QCD two-point sum rule method, where the quark, gluon and mixed vacuum condensates up to dimension eight are taken into account. The sum rule approach on the light-cone in its soft-meson approximation is used to explore the vertex $X_bB_{s}^{\ast}π$ and extract the strong coupling $% g_{X_bB_{s}^{\ast}π}$, which is a necessary ingredient to find the width of the $X_b \to B_s^{\ast}π^{+}$ decay process. The obtained predictions are compared with the experimental data of the D0 Collaboration, and results of other theoretical works.

hep-ph↗

arXiv2016

Mass and magnetic dipole moment of negative parity heavy baryons with spin--3/2

We calculate the mass and residue of the heavy spin--3/2 negative parity baryons with single heavy bottom or charm quark by the help of a two-point correlation function. We use the obtained results to investigate the diagonal radiative transitions among the baryons under consideration. In particular, we compute corresponding transition form factors via light cone QCD sum rules which are then used to obtain the magnetic dipole moments of the heavy spin--3/2 negative parity baryons. We remove the pollutions coming from the positive parity spin--3/2 and positive/negative parity spin--1/2 baryons by constructing sum rules for different Lorentz structures. We compare the results obtained with the existing theoretical predictions.

hep-ph↗

arXiv2016

Impact of finite density on spectroscopic parameters of decuplet baryons

The decuplet baryons, $Δ$, $Σ^{*}$, $Ξ^{*}$ and $Ω^{-}$, are studied in nuclear matter by using the in-medium QCD sum rules. By fixing the three momentum of the particles under consideration at the rest frame of the medium, the negative energy contributions are removed. It is obtained that the parameters of the $Δ$ baryon are more affected by the medium against the $Ω^{-}$ state, containing three strange quarks, whose mass and residue do not affected by the medium, considerably. We also find the vector and scalar self energies of these baryons in nuclear matter. By the recent progresses at $\bar{P}$ANDA experiment at FAIR and NICA facility it may be possible to study the in-medium properties of such states even the multi-strange $Ξ^{*}$ and $Ω^{-}$ systems in near future.

nucl-th↗

arXiv2016

Exploring $X(5568)$ as a meson molecule

The parameters, i.e. the mass and current coupling of the exotic $X(5568)$ state observed by the D0 Collaboration as well as the decay width of the process $X \to B_s^{0}π^{+}$ are explored using $B\bar{K}$ molecule assumption on its structure. Employed computational methods include QCD two-point and light-cone sum rules, latter being considered in the soft-meson approximation. The obtained results are compared with the data of the D0 Collaboration as well as with the predictions of the diquark-antidiquark model. This comparison strengthens a diquark-antidiquark picture for the $X(5568)$ state rather than a meson molecule structure.

hep-ph↗

arXiv2016

Width of the exotic $X_b(5568)$ state through its strong decay to $B_s^{0} π^{+}$

The width of the newly observed exotic state $X_b(5568)$ is calculated via its dominant strong decay to $% B_s^{0} π^{+}$ using the QCD sum rule method on the light-cone in conjunction with the soft-meson approximation. To this end, the vertex $X_{b}B_{s}π$ is studied and the strong coupling $g_{X_{b}B_{s}π}$ is computed employing for $X_b(5568)$ state the interpolating diquark-antidiquark current of the $[su][\overline{b}\overline{d}]$ type. The obtained prediction for the decay width of $X_b(5568)$ is confronted and a nice agreement found with the experimental data of the D0 Collaboration.

hep-ph↗

arXiv2016

Mass and decay constant of the newly observed exotic $X(5568)$ state

The mass and decay constant of the $X(5568)$ state newly observed by D0 Collaboration are computed within the two-point sum rule method using the diquark-antidiquark interpolating current. In calculations, the vacuum condensates up to eight dimensions are taken into account. The obtained result for the mass of the $X(5568)$ state is in a nice agreement with the experimental data.

hep-ph↗

arXiv2016

Charmed partner of the exotic $X(5568)$ state and its properties

The mass, decay constant and width of a hypothetical charmed partner $X_c$ of the newly observed exotic $X_b(5568)$ state are calculated using a technique of QCD sum rule method. The $X_c=[su][\overline{c}\overline{d}]$ state with $J^{P}=0^{+}$ is described employing two types of the diquark-antidiquark interpolating currents. The evaluation of the mass $m_{X_c}$ and decay constant $f_{X_c}$ is carried out utilizing the two-point sum rule method by including vacuum condensates up to eight dimensions. The widths of the decay channels $X_c \to D_s^{-} π^{+}$ and $X_c \to D^{0} K^{0}$ are also found. To this end, the strong couplings $g_{X_{c}D_{s}π}$ and $g_{X_{c}D K}$ are computed by means of QCD sum rules on the light-cone and soft-meson approximation.

hep-ph↗

arXiv2016

Strong $Z_c^{+}(3900)\rightarrow J/ψπ^{+}; η_{c} ρ^{+}$ decays in QCD

The widths of the strong decays $Z_c^{+}(3900)\to J/ψπ^{+}$ and $Z_c^{+}(3900)\to η_{c} ρ^{+}$ are calculated. To this end, the mass and decay constant of the exotic $Z_c^{+}(3900)$ state are computed by means of a two-point sum rule. The obtained results are then used to calculate the strong couplings $g_{Z_{c}J/ψπ}$ and $g_{Z_{c}η_{c} ρ}$ employing QCD sum rules on the light-cone supplied by a technique of the soft-meson approximation. We compare our predictions on the mass and decay widths with available experimental data and other theoretical results.

hep-ph↗

arXiv2016

Transition Form Factors of $χ_{b2}(1P)\rightarrow B_{c}\bar{l}ν$ in QCD

The form factors of the semileptonic $χ_{b2}(1P)\rightarrow B_{c}\bar{l}ν$ decay are calculated using the QCD sum rule approach. The results obtained are then used to estimate the decay widths of this transition in all lepton channels. The orders of decay rates indicate that this transition is accessible at LHC for all lepton channels.

hep-ph↗

arXiv2016

On the strong coupling $N^{()}N^{()}π$

We study the strong vertices $N^*Nπ$, $N^*N^*π$ and $NNπ$ in QCD, where $N^*$ denotes the negative parity $N (1535)$ state. We use the most general form of the interpolating currents to calculate the corresponding strong coupling constants. It is obtained that the coupling associated to $N^*Nπ$ vertex is strongly suppressed compared to those related to two other vertices. The strong coupling corresponding to $N^*N^*π$ is obtained to be roughly half of that of $NNπ$ vertex. We compare the obtained results on $N^*Nπ$ and $NNπ$ vertices with the existing predictions of other theoretical studies as well as those extracted from the experimental data.

hep-ph↗

arXiv2016

$ B_c B_c J/ψ$ Vertex Form Factor at Finite Temperature in the Framework of QCD Sum Rules Approach

The strong form factor of the $B_{c} B_{c}J/Ψ$ vertex is calculated in the framework of the QCD sum rules method at finite temperature. Taking into account additional operators appearing at finite temperature, thermal Wilson expansion is obtained and QCD sum rules are derived. While increasing temperature, the strong form factor remains unchanged up to $T\simeq100~MeV$ but slightly increases after this point. After $T\simeq160~MeV$, the form factor suddenly decreases up to $T\simeq170~MeV$. The obtained result of the coupling constant by fitting the form factor at $Q^2=-m^2_{offshell}$ at $T=0$ is in a very good agreement with the QCD sum rules calculations at vacuum. Our prediction can be checked in the future experiments.

hep-ph↗

arXiv2015

Strong $D^{}_sD_{s}η^{(\prime)}$ and $B^{}_sB_{s}η^{(\prime)}$ vertices from QCD light-cone sum rules

The strong $D^{*}_sD_{s}η^{(\prime)}$ and $B^{*}_sB_{s}η^{(\prime)}$ vertices are studied and the relevant couplings are calculated in the context of the light-cone QCD sum rule method with twist-4 accuracy by including the next-to-leading order corrections. In the analysis, both the quark and gluon components of the $η$ and $η^{\prime}$ mesons and the axial anomaly corrected higher twist distributions are included.

hep-ph↗

arXiv2015

Strong $Σ_bNB$ and $Σ_cND$ coupling constants in QCD

We study the strong interactions among the heavy bottom spin--1/2 $Σ_b$ baryon, nucleon and $B$ meson as well as the heavy charmed spin--1/2 $Σ_c$ baryon, nucleon and $D$ meson in the context of QCD sum rules. We calculate the corresponding strong coupling form factors defining these vertices by using a three point correlation function. We obtain the numerical values of the corresponding strong coupling constants via the most prominent structure entering the calculations.

hep-ph↗

arXiv2015

Positive and negative parity hyperons in nuclear medium

The effects of nuclear medium on the residue, mass and self energy of the positive and negative parity $Σ$, $Λ$ and $Ξ$ hyperons are investigated using the QCD sum rule method. In the calculations, the general interpolating currents of hyperons with an arbitrary mixing parameter are used. We compare the results obtained in medium with those of the vacuum and calculate the shifts in the corresponding parameters. It is found that the shifts on the residues in nuclear matter are over all positive for both the positive and negative parity hyperons, except for the positive parity $Σ$ hyperon that the shift is negative. The shifts on the masses of these baryons are obtained to be negative. The shifts on the residues and masses of negative parity states are large compared to those of positive parities. The maximum shift belongs to the residue of the negative parity $Λ$ hyperon. The vector self-energies gained by the positive parity baryons are large compared to the negative parities' vector self-energies. The maximum value of the vector self-energy belongs to the positive parity $Σ$ hyperon. The numerical values are compared with the existing predictions in the literature.

hep-ph↗