New hadronic states observed at BES II

The report includes the new observation of X(1835) in J/ψ→γη ^′ π ⁺ π ^-, the ωφ threshold enhancement in J/ψ→γωφ, the ωω structure in J/ψ→γωω and the broad 1^- structure at the low K ⁺ K ^- invariant-mass spectrum in J/ψ→K ⁺ K ^- π ⁰.     

Comments on preliminary data on the reactions e + e −→φ→γ f 0(980)→γπ0π0

Preliminary data on the reactions e ⁺ e ⁻→φ→γ f ₀(980)→γπ⁰π⁰ together with data on ππ scattering and the reactions J/ψ→φπ⁺π⁻ and K ⁻ p→π ⁺π⁻(Λ,Σ) are analyzed. The analysis shows that the mass of the f ₀(980) meson is = 950 MeV, and BR(φ→γf ₀→γπ⁰π⁰)≃ 1× 10⁻⁴, indicating that the f ₀(980) resonance is of a four-quark nature. Pis’ma Zh. éksp. Teor. Fiz. 67, No. 7, 445–449 (10 April 1998)     

Study of B c → J / ψ π , η c π decays with?perturbative?QCD?approach

The B _c →J/ψ π, η _c π decays are studied with the perturbative QCD approach. It is found that the form factors and for the B _c →J/ψ, η _c transitions and the branching ratios are sensitive to the parameters ω, v, f _J/ψ and , where ω and v are the parameters of the charmonium wave functions for a Coulomb potential and the harmonic-oscillator potential, respectively, and f _J/ψ and are the decay constants of the J/ψ and η _c mesons, respectively. The large branching ratios and the clear signals of the final states make the B _c →J/ψ π, η _c π decays the prospective channels for measurements at the hadron colliders.     

Quark-Antiquark states and their radiative transitions in terms of the spectral integral equation: Bottomonia

In the framework of the spectral integral equation, we consider the states and their radiative transitions. We reconstruct the interaction on the basis of data for the levels of the bottomonium states with J ^PC = 0⁻⁺, 1⁻⁻, 0⁺⁺, 1⁺⁺, 2⁺⁺ as well as the data for the radiative transitions γ (3S) → _γχbJ(2P) and γ(2S) → _γχbJ(1P) with J = 0, 1, 2. We calculate bottomonium levels with the radial quantum numbers n ≤ 6, their wave functions, and corresponding radiative transitions. The ratios Br[_χbJ(2P) → _γγ(2S)]/Br[_χbJ(2P) → _γγ(1S)] for J = 0, 1, 2 are found to be in agreement with data. We determine the component of the photon wave function using the data for the e ⁺ e ⁻ annihilation, e ⁺ e ⁻ → γ(9460), γ(10 023), γ(10 036), γ(10 580), γ(10 865), γ(11 019), and predict partial widths of the two-photon decays ηb0 → γγ, χb0 → γγ, χb2 → γγ for the radial excitation states below the threshold (n ≤ 3). The text was submitted by the authors in English.     

f0(980)-meson as a $$ \bar K $$ molecule in a phenomenological Lagrangian approach

We discuss a possible interpretation of the f ₀(980)-meson as a hadronic molecule —a bound state of K and mesons. Using a phenomenological Lagrangian approach we calculate the strong f ₀(980) → ππ and electromagnetic f ₀(980) → γγ decays. The compositeness condition provides a self-consistent method to determine the coupling constant between f ₀ and its constituents, K and . Form factors governing the decays of the f ₀(980) are calculated by evaluating the kaon loop integrals. The predicted f ₀(980) → ππ and f ₀(980) → γγ decay widths are in good agreement with available data and results of other theoretical approaches.     

Quark-gluonium content of the scalar-isoscalar states f0(980), f0(1300), f0(1500), f0(1750), and f0(1420 ?70+150 ) from hadronic decays

On the basis of the decay couplings f ₀ → ππ, K , ηη, ηη′ found earlier in the study of analytical (IJ ^PC =00⁺⁺) amplitude in the mass range 450–1900 MeV, we analyze the quark-gluonium content of the resonances f ₀(980), f ₀(1300), f ₀(1500), and f ₀(1750) and the broad state f ₀(1420 ₋₇₀ ⁺¹⁵⁰ ). The K-matrix technique used in the analysis makes it possible to evaluate the quark-gluonium content both for the states with switched-off decay channels (bare states, f ₀ ^bare ) and for the real resonances. We observe a significant change in the quark-gluonium composition in the evolution from bare states to real resonances, which is due to the mixing of states in the transitions f ₀(m ₁) → real mesons → f ₀ (m ₂) responsible for the decay processes as well. For f ₀(980), the analysis confirmed the dominance of q component, thus proving the n /s composition found in the study of the radiative decays. For the mesons f ₀(1300), f ₀(1500), and f ₀(1750), the hadronic decays do not allow one to determine uniquely the n , s , and gluonium components, providing relative percentage only. The analysis shows that the broad state f ₀(1420 ₋₇₀ ⁺¹⁵⁰ ) can mix with the flavor singlet q component only, which is consistent with gluonium origin of the broad resonance. From Yadernaya Fizika, Vol. 66, No. 4, 2003, pp. 772–785. Original English Text Copyright ? 2003 by Anisovich, Nikonov, Sarantsev. This article was submitted by the authors in English.     

Productions of X(1835) as baryonium with sizable gluon content

X(1835) has been treated as a baryonium with sizable gluon content, and to be almost flavor singlet. This picture allows us to rationally understand X(1835) production in J/ψ radiative decays, and its large couplings with pˉ, η^′ππ. The processes ϒ(1S) → γX(1835) and J/ψ → ωX(1835) have been examined. It has been found that Br(ϒ(1S) → γX(1835))Br(X(1835) → pˉ) < 6.45×10^-7, which is compatible with CLEO's recent experimental result (Phys. Rev. D 73, 032001 (2006) hep-ex/0510015). The branching fractions Br(J/ψ → ωX(1835)), Br(J/ψ → ρX(1835)) with X(1835) → pˉ and X(1835) → η^′π⁺π^- have been estimated by the quark-pair creation model. We show that they are heavily suppressed, so the signal of X(1835) is very difficult, if not impossible, to be observed in these processes. The experimental checks for these estimations are expected. The existence of the baryonium nonet is conjectured, and a model-independent derivation of their production branching fractions is presented.     

Towards B→Vγ decays at NNLO in SCET

We compute NNLO ((α_s ²)) corrections to the hard-scattering kernels entering the QCD factorization formula for B→Vγ decays, where V is a light vector meson. We give complete NNLO results for the dipole operators Q₇ and Q₈, and partial results for Q₁ valid in the large-β₀ limit and neglecting the NNLO correction from hard-spectator scattering. Large perturbative logarithms in the hard-scattering kernels are identified and resummed using soft-collinear effective theory. We use our results to estimate the branching fractions for B→K^*γ and B_s→φγ decays at NNLO and compare them with the current experimental data.     

CP -violation effects in the decays B ? → D * K *? and method for determining the weak phase γ

A method for determining the angle γ and the ratio of the amplitudes A _λ(B ⁻ → K ^*−) and A _λ)B ⁻ → D ^*0 K ^*−), r _Bλ, for all three vector-meson polarization states by using the decays B ^∓ → D ^* K ^*∓ is proposed. This method relies on the interference between the decays B ⁻ → D ^*0 K ^*− and B ⁻ → K ^*−, which arises if D ^*0 and decay to D ⁰/ π ⁰ and D ⁰/ γ, whereupon D ⁰ and mesons decay to common final hadron states. The doubly Cabibbo-suppressed modes of D ⁰-meson decay are chosen here to specify such final states. Original Russian Text ? V.A. Kovalchuk, 2007, published in Yadernaya Fizika, 2007, Vol. 70, No. 4, pp. 754–763.     

Quark-antiquark states and their radiative transitions in terms of the spectral integral equation: Charmonia

Earlier by the authors (Yad. Fiz. 70, 68 (2007)), the bƃ states were treated in the framework of the spectral integral equation, together with simultaneous calculations of radiative decays of the considered bottomonia. In the present paper, such a study is carried out for the charmonium states. We reconstruct the interaction in the c-c sector on the basis of the data for the charmonium levels with J _PC = 0⁻⁺, 1⁻⁻, 0⁺⁺, 1⁺⁺, 2⁺⁺, 1⁺⁻ and radiative transitions ψ(2S) → γχ _c0(1P), γχ _c1(1P), γχ _c2(1P), γχ _c(1S) and χ _c0(1P), χ _c1(1P), χ _c2(1P) → γJ/ψ. The c-c levels and their wave functions are calculated for the radial excitations with n ≤ 6. Also, we determine the c-c component of the photon wave function using the e ⁺ e ⁻-annihilation data: e ⁺ e ⁻ → J/ψ(3097), ψ(3686), ψ(3770), ψ(4040), ψ(4160), ψ(4415) and perform the calculations of the partial widths of the two-photon decays for the n = 1 states η _c0(1S), χ _c0(1P), χ _c2(1P) → γγ and n = 2 states η _c0(2S) → γγ, χ _c0(2P) → γγ. We discuss the status of the recently observed c-c states X(3872) and Y(3941): according to our results, the X(3872) can be either χ _c1(2P) or η _c2(1D), while Y(3941) is χ _c2(2P). The text was submitted by the authors in English.     

η(1475) and <Emphasis Type="Italic">f</Emphasis><Subscript>1</Subscript>(1420) resonances in the decay processes <Emphasis Type="Italic">J</Emphasis>/ψ → γ(ρρ, γρ<Superscript>0</Superscript>, γϕ) and in γγ* collisions

A scenario that removes the contradiction between the suppression of the η(1475) → γγ decay width and the strong coupling of η(1475) to the ρρ, ωω, and γρ⁰ channels and which leads to a nontrivial prediction for the manifestation of η(1475) in γγ*(Q ²) collisions is considered. Data on the dependence of the cross section for the reaction γγ*(Q ²) → K[`(K)]pK\bar K\pi on the photon virtuality in the energy range 1.35–1.55 GeV are explained here by the production of an η(1475) resonance in contrast to their standard interpretation in terms of the f <sub>1</sub>(1420) resonance. Experimental verification of the present explanation requires determining the spin-parity of resonance contributions, R, in the reactions γγ*(Q <sup>2</sup>) R → R → K[`(K)]pK\bar K\pi and J/ψ → γR → γ(γρ⁰, γϕ).     

Using the e ± μ? + E Tmiss signature in the search for supersymmetry and lepton-flavor violation in neutralino decays

The LHC (CMS) discovery potential in the search for supersymmetry and lepton-flavor violation in neutralino decays using the e ^± μ^∓ + E _T ^miss signature is studied. A detailed study is done for the CMS test points LM1-LM9. It is shown that, for the point LM1, it is possible to detect lepton-flavor violation in neutralino decays with lepton-flavor-violating branching Br( → μ^± e ^∓ ) ≥ 0.04 Br( → e ⁺ e ⁻ , μ⁺ μ⁻ ) for an integral luminosity of 10 fb⁻¹. The discovery potential in the mSUGRA-SUSY scenario with tan β = 10, sgn(μ) = + in the (m ₀, m _1/2) plane using the e ^± μ^∓ + E _T ^miss signature is determined. The text was submitted by the authors in English.     

Charm changing weak decays 1/2+ → 3/2+ + 0−/γ in SU(4) and SU(8) w

Weak decay modes (1/2⁺ → 3/2⁺ + 0⁻/γ) of charmed baryons are studied. Relations among the various decay amplitudes are derived in isospin, SU(3), SU(4) and SU(8) _w symmetries. Sextet dominance in SU(3) forbidsB(3) →D(10) +P(3*) decays. 20″ dominance in SU(4) specifies all the decays in terms of Θ⁻ decays. Weak decays of Θ* ₃ ⁺⁺ and Θ⁻ are also discussed. SU(8) _w symmetry predictsα , which is consistent with the experimental value.     

Precocious signs of new physics: Are we eight now?

Although the CKM-paradigm seems to work to an accuracy of about 15–20%, we emphasize that there are by now several indications that suggest the need for a beyond the Standard Model CP-odd phase. The value of sin 2β measured via the goldplated (tree) mode, B → ψK _s is smaller than the value deduced by using improved lattice matrix elements. The value of sin 2β measured via ‘penguin-dominated’ (loop) decays tends to be even smaller still. There is also a rather large difference between the direct CP asymmetries in → K ⁻ π ⁺ and B ⁻ → K ⁻ π ⁰ that is rather difficult to understand. More recently, CDF and D0 are finding about a 2σ signal in CP asymmetry in the corresponding gold-plated mode B _s → ψϕ. If true, this would be consistent with the indications of new CP-phase in penguin b → s transitions seen at B-factories. After describing these possible signs of trouble for the SM-CKM paradigm, we give a brief discussion of some of the BSM scenarios that could be the underlying cause of these deviations. In particular, we find that the data are quite suggestive of a fourth family with m′ _t in the range of 400–600 GeV as perhaps the simplest BSM candidate which ‘naturally’ explains the data.      

Radiative decays with light scalar mesons and singlet–octet mixing in ChPT

We study different types of radiative decays involving f₀(980) and a₀(980) mesons within a unified ChPT-based approach at one-loop level. Light scalar resonances, which are seen in the ππ, πη and KK̄ channels of the φ(1020) radiative decays and in the J/ψ decays are responsible for key questions of low-energy dynamics in the strong interaction sector, and the decays φ(1020)→γa₀(980), φ(1020)→γf₀(980), a₀(980)→γγ and f₀(980)→γγ are of interest for current experimental programs in Jülich, Frascati and Novosibirsk. From the theoretical point of view it is important to verify whether light scalar mesons are members of some flavor octet or nonet. We find a value for the mixing angle dictated by consistency with experiment and the coupling structures of the ChPT Lagrangian. The decay widths f₀(980)/a₀(980)→γρ(770)/ω(782), which have not been experimentally studied yet, are predicted. We also obtain several relations between the widths, which hold independently of the coupling constants and which represent a fingerprint of the model. PACS 11.30.Hv; 12.39.Fe; 13.30.Eg; 14.40.-n     

Feasibility study of model-independent approach to φ3 measurement using Dalitz plot analysis

In this paper, we present results of a feasibility study of a model-independent way to measure the angle φ₃ of the unitarity triangle. The method involves B^±→DK^± decays where the neutral D decays to the K⁰ _Sπ⁺π^- final state, together with the sample of decays of CP-tagged D mesons (produced, e.g. in ψ(3770)→DD̄ process) to the same final state. We consider different approaches to the extraction of φ₃ and obtain the expected statistical accuracy of the φ₃ measurement as a function of B and D_CP statistics. PACS 11.30.Er, 12.15.Hh     

The use of quantum-correlated D<Superscript>0</Superscript> decays for φ<Subscript>3</Subscript> measurement

We report the results of the Monte Carlo study of the method to determine the CKM angle φ₃ using Dalitz plot analysis of D⁰ produced in B^±→DK^± decay. Our main goal is to find the optimal strategy for a model-independent φ₃ extraction. We find that the analysis using decays of CP-tagged D mesons only cannot provide a completely model-independent measurement in the case of a limited data sample. The procedure involving binned analysis of B^±→DK^± and ψ(3770)→(K⁰ _Sπ⁺π^-)_D(K⁰ _Sπ⁺π^-)_D decays is proposed which, in contrast, allows not only to reach the φ₃ precision comparable to an unbinned model-dependent fit, but also provides an unbiased measurement with currently available data. PACS 11.30.Er; 12.15.Hh     

Final-state polarization in <Emphasis Type="Italic">B</Emphasis><Stack><Subscript><Emphasis Type="Italic">s</Emphasis></Subscript><Superscript>0</Superscript></Stack> decays

Certain B _s ⁰→V ₁ V ₂ decays (V _i is a vector meson) can be related by flavor SU(3) symmetry to corresponding B _d ⁰→V ₃ V ₄ decays. In this paper, we show that the final-state polarization can be predicted in the B _s ⁰ decay, assuming polarization measurements of the B _d ⁰ decay. This can be done within the scenario of penguin annihilation (PA), which has been suggested as an explanation of the unexpectedly large transverse polarization in B→φ K ^*. PA is used to estimate the breaking of flavor SU(3) symmetry in pairs of decays. Two of these for which PA makes a reasonably precise prediction of the size of SU(3) breaking are (B _s ⁰→φ φ,B _d ⁰→φ K ^0*) and ( ). The polarization measurement in the B _d ⁰ decay can be used to predict the transverse polarization in the B _s ⁰ decay and will allow for testing of PA as well as the other assumptions in the analysis.     

Near-threshold production of a0(980) mesons in πN and NN collisions and a0-f0 mixing

We consider near-threshold a ₀(980)-meson production in πN and NN collisions. An effective Lagrangian approach with one-pion exchange is applied to analyze different contributions to the cross section for different isospin channels. The Reggeon exchange mechanism is also evaluated for comparison. The results from πN reactions are used to calculate the contribution of the a ₀ meson to the cross sections and invariant mass distributions of the reactions and pp → ppK ⁺ K ⁻. It is found that the experimental observation of a ₀ ⁺ mesons in the reaction is much more promising than the observation of a ₀ ⁰ mesons in the reaction pp → ppK ⁺ K ⁻. Effects of isospin violation in the reactions pN → da ₀, pd → ³He(³H)a ₀, and dd → ⁴Hea ₀, which are induced by a ₀(980)-f ₀(980) mixing, are also analyzed. From Yadernaya Fizika, Vol. 66, No. 1, 2003, pp. 155–174. Original English Text Copyright ? 2003 by Kondratyuk, Bratkovskaya, Grishina, Büscher, Cassing, Str?her. This article was submitted by the authors in English.