Confinement Can Violate Momentum Sum Rule in QCD at High Energy Colliders

OpenAIRE

Nayak, Gouranga C

2018-01-01

Momentum sum rule in QCD is widely used at high energy colliders. Although the exact form of the confinement potential energy is not known but the confinement potential energy at large distance $r$ can not rise slower than ${\\rm ln}(r)$. In this paper we find that if the confinement potential energy at large distance $r$ rises linearly with $r$ (or faster) then the momentum sum rule in QCD is violated at the high energy colliders.

Lattice QCD evaluation of baryon magnetic moment sum rules

International Nuclear Information System (INIS)

Leinweber, D.B.

1991-05-01

Magnetic moment combinations and sum rules are evaluated using recent results for the magnetic moments of octet baryons determined in a numerical simulation of quenched QCD. The model-independent and parameter-free results of the lattice calculations remove some of the confusion and contradiction surrounding past magnetic moment sum rule analyses. The lattice results reveal the underlying quark dynamics investigated by magnetic moment sum rules and indicate the origin of magnetic moment quenching for the non-strange quarks in Σ. In contrast to previous sum rule analyses, the magnetic moments of nonstrange quarks in Ξ are seen to be enhanced in the lattice results. In most cases, the spin-dependent dynamics and center-of-mass effects giving rise to baryon dependence of the quark moments are seen to be sufficient to violate the sum rules in agreement with experimental measurements. In turn, the sum rules are used to further examine the results of the lattice simulation. The Sachs sum rule suggests that quark loop contributions not included in present lattice calculations may play a key role in removing the discrepancies between lattice and experimental ratios of magnetic moments. This is supported by other sum rules sensitive to quark loop contributions. A measure of the isospin symmetry breaking in the effective quark moments due to quark loop contributions is in agreement with model expectations. (Author) 16 refs., 2 figs., 2 tabs

Sum rules for baryonic vertex functions and the proton wave function in QCD

International Nuclear Information System (INIS)

Lavelle, M.J.

1985-01-01

We consider light-cone sum rules for vertex functions involving baryon-meson couplings. These sum rules relate the non-perturbative, and experimentally known, coupling constants to the moments of the wave function of the proton state. Our results for these moments are consistent with those obtained from QCD sum rules for two-point functions. (orig.)

Beautiful mesons from QCD spectral sum rules

International Nuclear Information System (INIS)

Narison, S.

1991-01-01

We discuss the beautiful meson from the point of view of the QCD spectral sum rules (QSSR). The bottom quark mass and the mixed light quark-gluon condensates are determined quite accurately. The decay constant f B is estimated and we present some arguments supporting this result. The decay constants and the masses of the other members of the beautiful meson family are predicted. (orig.)

Analysis of QCD sum rule based on the maximum entropy method

International Nuclear Information System (INIS)

Gubler, Philipp

2012-01-01

QCD sum rule was developed about thirty years ago and has been used up to the present to calculate various physical quantities like hadrons. It has been, however, needed to assume 'pole + continuum' for the spectral function in the conventional analyses. Application of this method therefore came across with difficulties when the above assumption is not satisfied. In order to avoid this difficulty, analysis to make use of the maximum entropy method (MEM) has been developed by the present author. It is reported here how far this new method can be successfully applied. In the first section, the general feature of the QCD sum rule is introduced. In section 2, it is discussed why the analysis by the QCD sum rule based on the MEM is so effective. In section 3, the MEM analysis process is described, and in the subsection 3.1 likelihood function and prior probability are considered then in subsection 3.2 numerical analyses are picked up. In section 4, some cases of applications are described starting with ρ mesons, then charmoniums in the finite temperature and finally recent developments. Some figures of the spectral functions are shown. In section 5, summing up of the present analysis method and future view are given. (S. Funahashi)

Singlet axial constant from QCD sum rules

International Nuclear Information System (INIS)

Belitskij, A.V.; Teryaev, O.V.

1995-01-01

We analyze the singlet axial form factor of the proton for small momentum transferred in the framework of QCD sum rules using the interpolating nucleon current which explicitly accounts for the gluonic degrees of freedom. As the result we come to the quantitative prediction of the singlet axial constant. It is shown that the bilocal power corrections play the most important role in the analysis. 21 refs., 3 figs

A Bayesian analysis of the nucleon QCD sum rules

International Nuclear Information System (INIS)

Ohtani, Keisuke; Gubler, Philipp; Oka, Makoto

2011-01-01

QCD sum rules of the nucleon channel are reanalyzed, using the maximum-entropy method (MEM). This new approach, based on the Bayesian probability theory, does not restrict the spectral function to the usual ''pole + continuum'' form, allowing a more flexible investigation of the nucleon spectral function. Making use of this flexibility, we are able to investigate the spectral functions of various interpolating fields, finding that the nucleon ground state mainly couples to an operator containing a scalar diquark. Moreover, we formulate the Gaussian sum rule for the nucleon channel and find that it is more suitable for the MEM analysis to extract the nucleon pole in the region of its experimental value, while the Borel sum rule does not contain enough information to clearly separate the nucleon pole from the continuum. (orig.)

Charmonium spectrum at finite temperature from a Bayesian analysis of QCD sum rules

Directory of Open Access Journals (Sweden)

Morita Kenji

2012-02-01

Full Text Available Making use of a recently developed method of analyzing QCD sum rules, we investigate charmonium spectral functions at finite temperature. This method employs the Maximum Entropy Method, which makes it possible to directly obtain the spectral function from the sum rules, without having to introduce any strong assumption about its functional form. Finite temperature effects are incorporated into the sum rules by the change of the various gluonic condensates that appear in the operator product expansion. These changes depend on the energy density and pressure at finite temperature, which are extracted from lattice QCD. As a result, J/ψ and ηc dissolve into the continuum already at temperatures around 1.0 ~ 1.1 Tc.

Λ-bar from QCD sum rules for heavy quarkonium

International Nuclear Information System (INIS)

Kiselev, V.V.

1994-01-01

Using a specific scheme of the QCD sum rules for heavy quarkonium int he leading approximation over the inverse heavy quark, one gets the estimate of the difference between the masses of the heavy meson and heavy quark Λ=o.59+-0.02 GeV. 10 refs

Old tensor mesons in QCD sum rules

International Nuclear Information System (INIS)

Aliev, T.M.; Shifman, M.A.

1981-01-01

Tensor mesons f, A 2 and A 3 are analyzed within the framework of QCD sum rules. The effects of gluon and quark condensate is accounted for phenomenologically. Accurate estimates of meson masses and coupling constants of the lowest-lying states are obtained. It is shown that the masses are reproduced within theoretical uncertainty of about 80 MeV. The coupling of f meson to the corresponding quark current is determined. The results are in good aqreement with experimental data [ru

QCD Sum Rule External Field Approach and Vacuum Susceptibilities

Institute of Scientific and Technical Information of China (English)

ZONG Hong-Shi; PING Jia-Lun; CHANG Chao-His; WANG Fan; ZHAO En-Guang

2002-01-01

Based on QCD sum rule three-point and two-point external field formulas respectively, the vector vacuumsusceptibilities are calculated at the mean-field level in the framework of the global color symmetry model. It is shownthat the above two approaches of determination of the vector vacuum susceptibility may lead to different results. Thereason of this contradiction is discussed.

Electromagnetic form factors of the ρ meson in light cone QCD sum rules

International Nuclear Information System (INIS)

Aliev, T.M.; Savci, M.

2004-01-01

We investigate the electromagnetic form factors of the ρ meson in light cone QCD sum rules. We find that the ratio of the magnetic and charge form factors is larger than 2 at all values of Q 2 (Q 2 ≥0.5 GeV 2 ). The values of the individual form factors at fixed values of Q 2 predicted by the light cone QCD sum rules are quite different compared to the results of other approaches. These results can be checked in the future, when more precise data on ρ meson form factors is available

Sum Rules in the CFL Phase of QCD at finite density

CERN Document Server

Manuel, C; Manuel, Cristina; Tytgat, Michel H.G.

2001-01-01

We study the asymmetry between the vector current and axial-vector current correlators in the colour-flavour locking (CFL) phase of QCD at finite density. Using Weinberg's sum rules, we compute the decay constant $f_\\pi$ of the Goldstone modes and find agreement with previous derivations. Using Das's sum rule, we also estimate the contribution of electromagnetic interactions to the mass of the charged modes. Finally, we comment on low temperature corrections to the effective field theory describing the Goldstone bosons.

What can we learn from sum rules for vertex functions in QCD

International Nuclear Information System (INIS)

Craigie, N.S.; Stern, J.

1982-04-01

We demonstrate that the light cone sum rules for vertex functions based on the operator product expansion and QCD perturbation theory lead to interesting relationships between various non-perturbative parameters associated with hadronic bound states (e.g. vertex couplings and decay constants). We also show that such sum rules provide a valuable means of estimating the matrix elements of the higher spin operators in the meson wave function. (author)

Renormalization group summation of Laplace QCD sum rules for scalar gluon currents

Directory of Open Access Journals (Sweden)

Farrukh Chishtie

2016-03-01

Full Text Available We employ renormalization group (RG summation techniques to obtain portions of Laplace QCD sum rules for scalar gluon currents beyond the order to which they have been explicitly calculated. The first two of these sum rules are considered in some detail, and it is shown that they have significantly less dependence on the renormalization scale parameter μ2 once the RG summation is used to extend the perturbative results. Using the sum rules, we then compute the bound on the scalar glueball mass and demonstrate that the 3 and 4-Loop perturbative results form lower and upper bounds to their RG summed counterparts. We further demonstrate improved convergence of the RG summed expressions with respect to perturbative results.

Beauty vector meson decay constants from QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)

2016-01-22

We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.

QCD sum rules in medium and the Okamoto-Nolen-Schiffer anomaly

International Nuclear Information System (INIS)

Hatsuda, T.; Hogaasen, H.; Prakash, M.

1991-01-01

The QCD sum-rule approach for a nuclear medium is developed. The medium dependence of the neutron-proton mass difference calculated from this approach gives effects in nuclei which have direct relevance for the resolution of the Okamoto-Nolen-Schiffer anomaly

QCD sum rules for D mesons. In-medium effects, chiral symmetry aspects and higher orders

Energy Technology Data Exchange (ETDEWEB)

Buchheim, Thomas

2017-04-11

Heavy open flavor mesons can serve as probes of hot and dense, strongly interacting matter in heavy-ion collisions suitable to mimic the extreme conditions shortly after the big-bang or in compact stars. Thus, the thorough theoretical investigation of medium modifications of D mesons is of utmost importance for the interpretation of the experimental data. Even at finite thermodynamic parameters, such as temperature and density, the non-perturbative framework of QCD sum rules allows for the determination of hadronic properties which are not accessible in perturbative quantum chromodynamics (QCD). By virtue of the separation of scales, long-range effects of hadrons are related to quark and gluon degrees of freedom, where features of the hadron spectrum are linked to condensates parameterizing the complex QCD ground state. This thesis furnishes the conception and calculus of QCD sum rules with emphasis on in-medium effects which are inevitable when addressing such effects in higher order contributions. In this regard, the notion and implications of medium-specific condensates are elucidated. Motivated by the significant numerical impact of four-quark condensates to the ρ meson sum rule we evaluate, for the first time, the corresponding in-medium mass-dimension 6 terms for D mesons tentatively employing the factorization hypothesis. Four-quark condensates containing heavy-quark operators may be included into the sum rule analysis utilizing the in-medium heavy-quark expansion made available here. Particular quark condensates are potential order parameters of chiral symmetry breaking, which is the mass generating mechanism of QCD giving the essential mass fraction to light hadrons. The interplay of altered spectral properties with changing in-medium QCD condensates, i. e. the chiral order parameters, can be studied with chiral partner sum rules. Although, introduced for light spin-1 mesons we foster their generalization to spin-0 open charm mesons demonstrating their

QCD sum rules for D mesons. In-medium effects, chiral symmetry aspects and higher orders

International Nuclear Information System (INIS)

Buchheim, Thomas

2017-01-01

Heavy open flavor mesons can serve as probes of hot and dense, strongly interacting matter in heavy-ion collisions suitable to mimic the extreme conditions shortly after the big-bang or in compact stars. Thus, the thorough theoretical investigation of medium modifications of D mesons is of utmost importance for the interpretation of the experimental data. Even at finite thermodynamic parameters, such as temperature and density, the non-perturbative framework of QCD sum rules allows for the determination of hadronic properties which are not accessible in perturbative quantum chromodynamics (QCD). By virtue of the separation of scales, long-range effects of hadrons are related to quark and gluon degrees of freedom, where features of the hadron spectrum are linked to condensates parameterizing the complex QCD ground state. This thesis furnishes the conception and calculus of QCD sum rules with emphasis on in-medium effects which are inevitable when addressing such effects in higher order contributions. In this regard, the notion and implications of medium-specific condensates are elucidated. Motivated by the significant numerical impact of four-quark condensates to the ρ meson sum rule we evaluate, for the first time, the corresponding in-medium mass-dimension 6 terms for D mesons tentatively employing the factorization hypothesis. Four-quark condensates containing heavy-quark operators may be included into the sum rule analysis utilizing the in-medium heavy-quark expansion made available here. Particular quark condensates are potential order parameters of chiral symmetry breaking, which is the mass generating mechanism of QCD giving the essential mass fraction to light hadrons. The interplay of altered spectral properties with changing in-medium QCD condensates, i. e. the chiral order parameters, can be studied with chiral partner sum rules. Although, introduced for light spin-1 mesons we foster their generalization to spin-0 open charm mesons demonstrating their

QCD sum rules for the decay amplitudes of pseudoscalar mesons

International Nuclear Information System (INIS)

Narison, S.

1981-07-01

Bounds on the π and K meson decay amplitudes are obtained to a good accuracy from QCD sum rules of the Laplace transform type. A relation between fsub(π) and the rho meson coupling to the photon is given. Using the heavy quarks q 2 =0 sum rule to two loops we find our best bounds: fsub(D) approximately < (101+-25) MeV and fsub(F) approximately < (147+-41.6) MeV to be compared to fsub(π) approximately 93.3 MeV. We also derive a relation between the D and F meson masses and the charm quark mass. Our results are extended to the beautiful B mesons. (author)

Nuclear Symmetry Energy with QCD Sum Rule

International Nuclear Information System (INIS)

Jeong, K.S.; Lee, S.H.

2013-01-01

We calculate the nucleon self-energies in an isospin asymmetric nuclear matter using QCD sum rule. Taking the difference of these for the neutron and proton enables us to express an important part of the nuclear symmetry energy in terms of local operators. Calculating the operator product expansion up to mass dimension six operators, we find that the main contribution to the difference comes from the iso-vector scalar and vector operators, which is reminiscent to the case of relativistic mean field type theories where mesons with aforementioned quantum numbers produce the difference and provide the dominant mechanism for nuclear symmetry energy. (author)

gsub(ωrhoπ) coupling constant from QCD sum rules

International Nuclear Information System (INIS)

Eletsky, V.L.; Ioffe, B.L.; Kogan, Ya.I.

1982-01-01

QCD sum rules for the vertex function of two vector and one axial vector currents are used to calculate the gsub(ωrhoπ) coupling constant (where gsub(ωrhoπ) is a transition coupling constant for ω → rhoπ process). The obtained value, gsub(ωrhoπ) approximately 17 GeV -1 is in a good agreement with experimental data

Calculation of electromagnetic rhoπ formfactor from QCD sum rules

International Nuclear Information System (INIS)

Eletskij, V.L.; Kogan, Ya.I.

1982-01-01

Electromagnetic rhoπγ form factor at intermediate momentum transfer, 0.7 GeV 2 2 2 , is calculated using QCD sum rules for the vertex function of two vector and one axial-vector currents. In this region the results obtained are consistent within 25% accuracy with the vector meson dominance model predictions and can be regarded as its theoretical ustification

Sum rules for the spontaneous chiral symmetry breaking parameters of QCD

International Nuclear Information System (INIS)

Craigie, N.S.; Stern, J.

1981-03-01

We discuss in the spirit of the work of Shifman, Vainshtein and Zakharov (SVZ), sum rules involving current-current vacuum correlation functions, whose Wilson expansion starts off with the operators anti qq or (anti qq) 2 , and thus provide information about the chiral symmetry breaking parameters of QCD. We point out that under the type of crude approximations made by SVZ, a value of sub(vac) (250MeV) 3 is obtained from one of these sum rules, in agreement with current expectations. Further we show that a Borel transformed version of the Weinberg sum rule, for VV - AA, current products seem only to make sense for an A 1 mass close to 1.3GeV and it makes little sense with the current algebra mass Msub(A)=anti 2M. We also give an estimate for the chiral symmetry breaking parameters μ 1 6 =2 2 (anti qsub(L) lambda sup(a)γsub(μ)qsub(L))(anti qsub(R) lambdasup(a) γsup(μ)qsub(R)) >sub(vac) entering in the Weinberg sum rules and μ 2 6 =g 2 sub(vac) entering in a new sum rule we propose involving antisymmetric tensor currents J=anti q σsub(μnu) q. (author)

Spectral representation and QCD sum rules in hot nuclear matter

International Nuclear Information System (INIS)

Mallik, S.; Sarkar, Sourav

2009-01-01

We construct the spectral representation of spinsor two-point functions in medium, that is, at finite temperature and chemical potential. We first deal with the free spinor two-point function. Then we construct the same for interacting fields leading to the Kaellen-Lehmann representation. It is emphasised that although these two point functions have the structure of 2 x 2 matrices in the real time formulation of field theory, any one component actually suffices to describe the dynamics of the system. Our construction is then applied to write the QCD sum rules for two-point function of nucleon currents in medium. We discuss a subtracted version to increase the sensitivity of such a sum rule and point out how it differs from a conventional one. (author)

Neutron matter within QCD sum rules

Science.gov (United States)

Cai, Bao-Jun; Chen, Lie-Wen

2018-05-01

The equation of state (EOS) of pure neutron matter (PNM) is studied in QCD sum rules (QCDSRs ). It is found that the QCDSR results on the EOS of PNM are in good agreement with predictions by current advanced microscopic many-body theories. Moreover, the higher-order density terms in quark condensates are shown to be important to describe the empirical EOS of PNM in the density region around and above nuclear saturation density although they play a minor role at subsaturation densities. The chiral condensates in PNM are also studied, and our results indicate that the higher-order density terms in quark condensates, which are introduced to reasonably describe the empirical EOS of PNM at suprasaturation densities, tend to hinder the appearance of chiral symmetry restoration in PNM at high densities.

Analysis of the doubly heavy baryons in the nuclear matter with the QCD sum rules

International Nuclear Information System (INIS)

Wang, Zhi-Gang

2012-01-01

In this article, we study the doubly heavy baryon states Ξ cc , Ω cc , Ξ bb and Ω bb in the nuclear matter using the QCD sum rules, and derive three coupled QCD sum rules for the masses, vector self-energies and pole residues. The predictions for the mass-shifts in the nuclear matter ΔM Ξ cc =-1.11simGeV, ΔM Ω cc =-0.33∝GeV, ΔM Ξ bb =-3.37∝GeV and ΔM Ω bb =-1.05∝GeV can be confronted with experimental data in the future. (orig.)

Finite temperature QCD sum rule and the ρ-meson

International Nuclear Information System (INIS)

Liu Jueping; Jin Yaping

1995-01-01

The contributions from the three-gluon condensates to the finite temperature QCD sum rule for the ρ-meson are calculated, and then the dependence of the properties of the ρ-meson upon temperature is investigated in a string model of condensates. The results show that the parameters characterizing the properties of the ρ-meson change noticeably when the temperature closes to the critical temperature of the condensates, and if the critical temperatures of condensates are the same

Endpoint behavior of the pion distribution amplitude in QCD sum rules with nonlocal condensates

International Nuclear Information System (INIS)

Mikhailov, S. V.; Pimikov, A. V.; Stefanis, N. G.

2010-01-01

Starting from the QCD sum rules with nonlocal condensates for the pion distribution amplitude, we derive another sum rule for its derivative and its ''integral derivatives''--defined in this work. We use this new sum rule to analyze the fine details of the pion distribution amplitude in the endpoint region x∼0. The results for endpoint-suppressed and flattop (or flatlike) pion distribution amplitudes are compared with those we obtained with differential sum rules by employing two different models for the distribution of vacuum-quark virtualities. We determine the range of values of the derivatives of the pion distribution amplitude and show that endpoint-suppressed distribution amplitudes lie within this range, while those with endpoint enhancement--flat-type or Chernyak-Zhitnitsky like--yield values outside this range.

Determination of baryon and baryonic resonance masses from QCD sum rules. Strange baryons

International Nuclear Information System (INIS)

Belyaev, V.M.; Ioffe, B.L.

1982-01-01

The mass differences in baryonic octet Jsup(P)=1/2sup(+), decuplet Jsup(P)=3/2sup(+) and in octet Jsup(P)=3/2sup(-) are calculated basing on the QCD sum rules. The mass differences are expressed through two QCD parameters: the strange current qUark mass and the value of the quark condensate. At the properly chosen values of these parameters all of the mass differences are in a good agreement with experiment

QCD Sum-Rule Calculation of the Kinetic Energy and Chromo-Interaction of Heavy Quarks Inside Mesons

CERN Document Server

Neubert, M

1996-01-01

We present a QCD sum-rule determination of the heavy-quark kinetic energy inside a heavy meson, $-\\lambda_1/2 m_Q$, which is consistent with the field-theory analog of the virial theorem. We obtain $-\\lambda_1\\approx (0.10\\pm 0.05)~\\mbox{GeV}^2$, significantly smaller than a previous sum-rule result, but in good agreement with recent determinations from the analysis of inclusive decays. We also present a new determination of the chromo-magnetic interaction, yielding $\\lambda_2(m_b)=(0.15\\pm 0.03)~\\mbox{GeV}^2$. This implies $m_{B^*}^2-m_B^2=(0.60\\pm 0.12)~\\mbox{GeV}^2$, in good agreement with experiment. As a by-product of our analysis, we derive the QCD sum rules for the three form factors describing the meson matrix element of a velocity-changing current operator containing the gluon field-strength tensor.

Energy and Regge residues in quantum-mechanical ''QCD'' sum rules

International Nuclear Information System (INIS)

Durand, B.; Durand, L.

1986-01-01

It was shown recently by Fishbane, Kaus, and Gasiorowicz that the residues at the poles of quantum-mechanical two-point functions for arbitrary angular momenta l have an incorrect l dependence when calculated by the sum-rule method used for the analogous problem in QCD. Knowledge of the residues is of interest since they are directly related to particle couplings and decay widths. We develop reliable expressions for the energy and Regge residues using semiclassical methods

QCD effects to Bjorken unpolarized sum rule for νN deep-inelastic scattering

International Nuclear Information System (INIS)

Alekhin, S I; Kataev, A L

2003-01-01

The possibility of the first measurement of Bjorken unpolarized sum rule for F 1 structure function of νN deep-inelastic scattering at neutrino factories is commented. The brief summary of various theoretical contributions to this sum rule is given. Using the next-to-leading set of parton distributions functions, we simulate the expected Q 2 -behaviour and emphasize that its measurement can allow us to determine the value of the QCD strong coupling constant α s with reasonable theoretical uncertainty, dominated by the ambiguity in the existing estimates of the twist-4 non-perturbative 1/Q 2 -effect

Perturbative corrections to Λ_b→Λ form factors from QCD light-cone sum rules

International Nuclear Information System (INIS)

Wang, Yu-Ming; Shen, Yue-Long

2016-01-01

We compute radiative corrections to Λ_b→Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ_b-baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ_b-baryon correlation function is justified at leading power in Λ/m_b, with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at O(α_s) shift the Λ_b→Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ_b→Λ from factors we further investigate several decay observables in the electro-weak penguin Λ_b→Λ ℓ"+ℓ"− transitions in the factorization limit (i.e., ignoring the “non-factorizable' hadronic effects which cannot be expressed in terms of the Λ_b→Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

What do QCD sum rules tell us about dense matter?

International Nuclear Information System (INIS)

Cohen, T.D.; Washington Univ., Seattle, WA

1995-01-01

The QCD sum rule approach to the properties of hadrons in both the vacuum and in nuclear matter is discussed. The primary limitation for the nuclear matter case is the absence of reliable phenomenological information about the form of the spectral function and about the value of certain four quark condensates. The approach gives moderate evidence in support of the Dirac phenomenology picture of strong attractive Lorentz scalar and repulsive Lorentz vector optical potentials. The approach gives weak evidence for decreasing vector meson masses in medium. (orig.)

The α3S corrections to the Bjorken sum rule for polarized electro-production and to the Gross-Llewellyn Smith sum rule

International Nuclear Information System (INIS)

Larin, S.A.; Nationaal Inst. voor Kernfysica en Hoge-Energiefysica; Vermaseren, J.A.M.

1990-01-01

The next-next-to-leading order QCD corrections to the Gross-Llewellyn Smith sum rule for deep inelastic neutrino-nucleon scattering and to the Bjorken sum rule for polarized electron-nucleon scattering have been computed. This involved the proper treatment of γ 5 inside the loop integrals with dimensional regularization. It is found that the difference between the two sum rules are entirely due to a class of 6 three loop graphs and is of the order of 1% of the leading QCD term. Hence the Q 2 behavior of both sum rules should be the same if the physics is described adequately by the lower order terms of perturbative QCD. (author). 12 refs.; 2 figs.; 4 tabs

Iso-vector form factors of the delta and nucleon in QCD sum rules

International Nuclear Information System (INIS)

Ozpineci, A.

2012-01-01

Form factors are important non-perturbative properties of hadrons. They give information about the internal structure of the hadrons. In this work, iso-vector axial-vector and iso-vector tensor form factors of the nucleon and the iso-vector axial-vector Δ→N transition form factor calculations in QCD Sum Rules are presented.

The off shell ρ endash ω mixing in the QCD sum rules

International Nuclear Information System (INIS)

Hatsuda, T.

1993-01-01

The q 2 dependence of the ρ - ω mixing amplitude is analyzed with the use of the QCD sum rules and the dispersion relation. In going off shell the mixing decreases, changes sign at q 2 ≅ 0.4 m ρ 2 > 0, and is negative in the space-like region. Implications of this result to the isospin breaking part of the nuclear force are discussed

Analysis of the scalar doubly charmed hexaquark state with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang [North China Electric Power University, Department of Physics, Baoding (China)

2017-09-15

In this article, we study the scalar-diquark-scalar-diquark-scalar-diquark type hexaquark state with the QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension 16. We obtain a lowest hexaquark mass of 6.60{sup +0.12}{sub -0.09} GeV, which can be confronted with the experimental data in the future. (orig.)

Leptonic decay constants of heavy quarkonia in effective QCD sum rules

International Nuclear Information System (INIS)

Kiselev, V.V.

1992-01-01

The QCD sum rule scheme, which allows one effectively to take into account the heavy quarkonium peculiarities such as nonrelativistic motion and large mass values of the quarks is considered. The phenomenological scaling law is derived for the leptonic constants with the use of the heavy quarkonium mass spectra. The law describes the data on the values of f φ , f ψ and fγ rather good and predicts f B C . 12 refs.; 2 tabs

Spectral function sum rules in quantum chromodynamics. I. Charged currents sector

International Nuclear Information System (INIS)

Floratos, E.G.; Narison, Stephan; Rafael, Eduardo de.

1978-07-01

The Weinberg sum rules of the algebra of currents are reconsidered in the light of quantum chromodynamics (QCD). The authors derive new finite energy sum rules which replace the old Weinberg sum rules. The new sum rules are convergent and the rate of convergence is explicitly calculated in perturbative QCD at the one loop approximation. Phenomenological applications of these sum rules in the charged current sector are also discussed

QCD determination of the A1-p-π system through vertex light-cone sum rules

International Nuclear Information System (INIS)

Craigie, N.S.; Paver, N.; Riazzudin

1986-01-01

We analyze the rho-A 1 -π system within the context of vertex light-cone sum rules, which are believed to be rigorously satisfied in QCD. It is pointed out that these sum rules provide very strong constraints on the hardronic spectrum and with additional assumptions lead to new predictions, which go significantly beyond those obtained from current algebra in the past. In particular, we report some new results about the rho-A 1 -π couplings and the various transitions form factors in tau-semi-leptonic decays. (orig.)

Scalar Hidden-Charm Tetraquark States with QCD Sum Rules

Science.gov (United States)

Di, Zun-Yan; Wang, Zhi-Gang; Zhang, Jun-Xia; Yu, Guo-Liang

2018-02-01

In this article, we study the masses and pole residues of the pseudoscalar-diquark-pseudoscalar-antidiquark type and vector-diquark-vector-antidiquark type scalar hidden-charm cu\\bar{c}\\bar{d} (cu\\bar{c}\\bar{s}) tetraquark states with QCD sum rules by taking into account the contributions of the vacuum condensates up to dimension-10 in the operator product expansion. The predicted masses can be confronted with the experimental data in the future. Possible decays of those tetraquark states are also discussed. Supported by the National Natural Science Foundation of China under Grant No. 11375063, the Fundamental Research Funds for the Central Universities under Grant Nos. 2016MS155 and 2016MS133

Dispersive approach to the axial anomaly. The t'Hooft's principle and QCD sum rules

International Nuclear Information System (INIS)

Horejsi, J.; Teryaev, O.; Veretin, O.; )

1997-01-01

The dispersive approach to the axial anomaly is revisited. Considering the familiar VVA triangle graph, the anomalous Ward identity is proved in the case of the arbitrary external momenta. It is also commented on a recent claim that the anomaly pole in QCD fails to reproduce the pion pole. In this connection it is emphasized that there is no need to introduce a massless axial meson in the chiral limit. In the framework of QCD sum rules method a constraint for the Borel transform of relevant form factors imposed by the anomaly is considered [ru

QCD light-cone sum rule estimate of charming penguin contributions in B→ππ

International Nuclear Information System (INIS)

Khodjamirian, A.; Mannel, Th.; Melic, B.

2003-01-01

Employing the QCD light-cone sum rule approach we calculate the B→ππ hadronic matrix element of the current-current operator with c quarks in the penguin topology (''charming penguin''). The dominant contribution to the sum rule is due to the c-quark loop at short distances and is of O(α s ) with respect to the factorizable B→ππ amplitude. The effects of soft gluons are suppressed at least by O(α s m b -2 ). Our result indicates that sizable nonperturbative effects generated by charming penguins at finite m b are absent. The same is valid for the penguin contractions of the current-current operators with light quarks

QCD light-cone sum rule estimate of charming penguin contributions in B→ππ

International Nuclear Information System (INIS)

Khodjamirian, A.; Mannel, Th.; Melic, B.

2003-01-01

Employing the QCD light-cone sum rule approach we calculate the B→ππ hadronic matrix element of the current-current operator with c quarks in the penguin topology ('charming penguin'). The dominant contribution to the sum rule is due to the c-quark loop at short distances and is of O(α s ) with respect to the factorizable B→ππ amplitude. The effects of soft gluons are suppressed at least by O(α s m b -2 ). Our result indicates that sizable nonperturbative effects generated by charming penguins at finite m b are absent. The same is valid for the penguin contractions of the current-current operators with light quarks

Searching for hidden-charm baryonium signals in QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Chen, Hua-Xing; Zhou, Dan [Beihang University, School of Physics, Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beijing (China); Chen, Wei [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, SK (Canada); Liu, Xiang [Lanzhou University, School of Physical Science and Technology, Lanzhou (China); Lanzhou University, Research Center for Hadron and CSR Physics, Institute of Modern Physics of CAS, Lanzhou (China); Zhu, Shi-Lin [Peking University, School of Physics, State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Peking University, Center of High Energy Physics, Beijing (China)

2016-11-15

We give an explicit QCD sum rule investigation for hidden-charm baryonium states with the quark content u anti ud anti dc anti c, spin J = 0/1/2/3, and of both positive and negative parities. We systematically construct the relevant local hidden-charm baryonium interpolating currents, which can actually couple to various structures, including hidden-charm baryonium states, charmonium states plus two pions, and hidden-charm tetraquark states plus one pion, etc. We do not know which structure these currents couple to at the beginning, but after sum rule analyses we can obtain some information. We find some of them can couple to hidden-charm baryonium states, using which we evaluate the masses of the lowest-lying hidden-charm baryonium states with quantum numbers J{sup P} = 2{sup -}/3{sup -}/0{sup +}/1{sup +}/2{sup +} to be around 5.0 GeV. We suggest to search for hidden-charm baryonium states, especially the one of J = 3{sup -}, in the D-wave J/ψππ and P-wave J/ψρ and J/ψω channels in this energy region. (orig.)

Magnetic moment for the negative parity Λ→Σ0 transition in light cone QCD sum rules

Directory of Open Access Journals (Sweden)

T.M. Aliev

2016-07-01

Full Text Available The magnetic moment of the Λ→Σ0 transition between negative parity baryons is calculated in framework of the QCD sum rules approach by using the general form of the interpolating currents. The pollution arising from the positive-to-positive, and positive-to-negative parity baryons is eliminated by constructing the sum rules for different Lorentz structures. A comparison of our result with the predictions of the results of other approaches for the positive parity baryons is presented.

Matrix elements of four-quark operators relevant to life time difference ΔΓBs from QCD sum rules

International Nuclear Information System (INIS)

Huang, C.S.; Zhang Ailin; Zhu, S.L.

2001-01-01

We extract the matrix elements of four-quark operators O L,S relevant to the B s and anti B s life time difference from QCD sum rules. We find that the vacuum saturation approximation works reasonably well, i.e., within 10%. We discuss the implications of our results and compare them with a recent lattice QCD determination. (orig.)

Subtracted Dispersion Relations for In-medium Meson Correlators in QCD Sum Rules

Energy Technology Data Exchange (ETDEWEB)

Florkowski, W; Broniowski, W [The H. Niewodniczanski Institute of Nuclear Physics, Cracow (Poland)

1999-01-01

We analyze subtracted dispersion relations for meson correlators at finite baryon density and temperature. Such relations are needed for QCD sum rules. We point out that importance of scattering terms, as well as finite, well-defined subtraction constants. Both are necessary for consistency, in particular for the equality of the longitudinal and transverse correlators in the limit of the vanishing three-momentum of mesons relative to the medium. We present detailed calculations in various mesonic channels of the Fermi gas of nucleons. (author)

gDsDK*0 and gBsDK*0 coupling constants in QCD sum rules

International Nuclear Information System (INIS)

Şahin, S; Sundu, H; Azizi, K

2012-01-01

In the present study, we calculate the strong coupling constants g D s DK* 0 (800) and g B s DK* 0 (800) within the three-point QCD sum rules approach. We evaluate the correlation function of the considered vertices taking into account both D[B] and K* 0 (800) mesons as off-shell states.

Isospin-breaking nuclear forces in QCD sum rules and Nolen-Schiffer anomaly

International Nuclear Information System (INIS)

Drukarev, E.G.; Ryskin, M.G.

1994-01-01

We use QCD sum rules to investigate isospin-breaking effects in nuclear matter. The isospin-breaking condensate left angle NM vertical stroke uu-dd vertical stroke NM right angle is shown to play an important role. In a reasonable model the neutron becomes (0.9±0.6) MeV more bound than the proton, providing a possible solution for the Nolen-Schiffer anomaly. The various contributions to the value are analysed. The possible consequences for nucleon-nucleon isospin-breaking forces are discussed. ((orig.))

Scaling properties of S-wave level density for heavy quarkonium from QCD sum rules

International Nuclear Information System (INIS)

Kiselev, V.V.

1994-01-01

In the framework of a specific scheme of the QCD sum rules for S-wave of the heavy quarkonium one derives an expression, relating the energetic density of quarkonium states and universal characteristics in the heavy quarkonium physics, such as the difference between the masses of a heavy quark Q and meson and the number of heavy quarkonium levels below the threshold decay. 20 refs

Perturbative corrections to Λ{sub b}→Λ form factors from QCD light-cone sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Yu-Ming [Fakultät für Physik, Universität Wien,Boltzmanngasse 5, 1090 Vienna (Austria); Physik Department T31, Technische Universität München,James-Franck-Straße 1, D-85748 Garching (Germany); Shen, Yue-Long [College of Information Science and Engineering, Ocean University of China,Songling Road 238, Qingdao, Shandong 266100 (China)

2016-02-29

We compute radiative corrections to Λ{sub b}→Λ from factors, at next-to-leading logarithmic accuracy, from QCD light-cone sum rules with Λ{sub b}-baryon distribution amplitudes. Employing the diagrammatic approach factorization of the vacuum-to-Λ{sub b}-baryon correlation function is justified at leading power in Λ/m{sub b}, with the aid of the method of regions. Hard functions entering the factorization formulae are identical to the corresponding matching coefficients of heavy-to-light currents from QCD onto soft-collinear effective theory. The universal jet function from integrating out the hard-collinear fluctuations exhibits richer structures compared with the one involved in the factorization expressions of the vacuum-to-B-meson correlation function. Based upon the QCD resummation improved sum rules we observe that the perturbative corrections at O(α{sub s}) shift the Λ{sub b}→Λ from factors at large recoil significantly and the dominant contribution originates from the next-to-leading order jet function instead of the hard coefficient functions. Having at hand the sum rule predictions for the Λ{sub b}→Λ from factors we further investigate several decay observables in the electro-weak penguin Λ{sub b}→Λ ℓ{sup +}ℓ{sup −} transitions in the factorization limit (i.e., ignoring the “non-factorizable' hadronic effects which cannot be expressed in terms of the Λ{sub b}→Λ from factors), including the invariant mass distribution of the lepton pair, the forward-backward asymmetry in the dilepton system and the longitudinal polarization fraction of the leptonic sector.

QCD sum-rules analysis of vector (1-) heavy quarkonium meson-hybrid mixing

Science.gov (United States)

Palameta, A.; Ho, J.; Harnett, D.; Steele, T. G.

2018-02-01

We use QCD Laplace sum rules to study meson-hybrid mixing in vector (1-) heavy quarkonium. We compute the QCD cross-correlator between a heavy meson current and a heavy hybrid current within the operator product expansion. In addition to leading-order perturbation theory, we include four- and six-dimensional gluon condensate contributions as well as a six-dimensional quark condensate contribution. We construct several single and multiresonance models that take known hadron masses as inputs. We investigate which resonances couple to both currents and so exhibit meson-hybrid mixing. Compared to single resonance models that include only the ground state, we find that models that also include excited states lead to significantly improved agreement between QCD and experiment. In the charmonium sector, we find that meson-hybrid mixing is consistent with a two-resonance model consisting of the J /ψ and a 4.3 GeV resonance. In the bottomonium sector, we find evidence for meson-hybrid mixing in the ϒ (1 S ) , ϒ (2 S ), ϒ (3 S ), and ϒ (4 S ).

Thermal Properties of Light Tensor Mesons via QCD Sum Rules

Directory of Open Access Journals (Sweden)

K. Azizi

2015-01-01

Full Text Available The thermal properties of f2(1270, a2(1320, and K2*(1430 light tensor mesons are investigated in the framework of QCD sum rules at finite temperature. In particular, the masses and decay constants of the light tensor mesons are calculated taking into account the new operators appearing at finite temperature. The numerical results show that, at the point at which the temperature-dependent continuum threshold vanishes, the decay constants decrease with amount of (70–85% compared to their vacuum values, while the masses diminish about (60–72% depending on the kinds of the mesons under consideration. The results obtained at zero temperature are in good consistency with the experimental data as well as the existing theoretical predictions.

The Gross-Llewellyn Smith sum rule

International Nuclear Information System (INIS)

Scott, W.G.

1981-01-01

We present the most recent data on the Gross-Llewellyn Smith sum rule obtained from the combined BEBC Narrow Band Neon and GGM-PS Freon neutrino/antineutrino experiments. The data for the Gross-Llewellyn Smith sum rule as a function of q 2 suggest a smaller value for the QCD coupling constant parameter Λ than is obtained from the analysis of the higher moments. (author)

On contribution of instantons to nucleon sum rules

International Nuclear Information System (INIS)

Dorokhov, A.E.; Kochelev, N.I.

1989-01-01

The contribution of instantons to nucleon QCD sum rules is obtained. It is shown that this contribution does provide stabilization of the sum rules and leads to formation of a nucleon as a bound state of quarks in the instanton field. 17 refs.; 3 figs

The calculation of the quark distribution amplitudes of decuplet baryons by means of QCD sum rules

International Nuclear Information System (INIS)

Bonekamp, J.

1994-11-01

Using the QCD sum rule technique, we derive the quark distribution amplitudes of the decuplet memebers Δ(1232), Σ * (1385), Ξ * (1530) and Ω(1672). Generalizing the treatment of the Bethe-Salpeter amplitude, we can distinguish spin- and orbital- angular momentum parts of the quark distributions and establish separate sum rules for the contributions. Projecting out the angular momentum 1/2 contributions, we obtain sum rules which are saturated by the lowest resonance in the given iso spin channel, thus resolving deficiencies of the standard approach. We find that for helicity 1/2 the spin part of the quark distributions is asymmetric. Also the orbital angular momentum contributions are extremely asymmetric and tend to decrease the asymmetry of the spin part. As a result of SU(3) symmetry breaking, configuration mixing occurs and the decuplet baryons Σ * and Ξ * receive octet contributions. The antisymmetric part of these octet contributions is calculated. (orig.)

Masses of open-flavour heavy-light hybrids from QCD sum-rules

Energy Technology Data Exchange (ETDEWEB)

Ho, J. [Department of Physics and Engineering Physics, University of Saskatchewan,Saskatoon, SK, S7N 5E2 (Canada); Harnett, D. [Department of Physics, University of the Fraser Valley,Abbotsford, BC, V2S 7M8 (Canada); Steele, T.G. [Department of Physics and Engineering Physics, University of Saskatchewan,Saskatoon, SK, S7N 5E2 (Canada)

2017-05-29

We use QCD Laplace sum-rules to predict masses of open-flavour heavy-light hybrids where one of the hybrid’s constituent quarks is a charm or bottom and the other is an up, down, or strange. We compute leading-order, diagonal correlation functions of several hybrid interpolating currents, taking into account QCD condensates up to dimension-six, and extract hybrid mass predictions for all J{sup P}∈{0"±, 1"±}, as well as explore possible mixing effects with conventional quark-antiquark mesons. Within theoretical uncertainties, our results are consistent with a degeneracy between the heavy-nonstrange and heavy-strange hybrids in all J{sup P} channels. We find a similar mass hierarchy of 1{sup +}, 1{sup −}, and 0{sup +} states (a 1{sup +} state lighter than essentially degenerate 1{sup −} and 0{sup +} states) in both the charm and bottom sectors, and discuss an interpretation for the 0{sup −} states. If conventional meson mixing is present the effect is an increase in the hybrid mass prediction, and we estimate an upper bound on this effect.

The magnetic moment of the Z_c(3900) as an axialvector tetraquark state with QCD sum rules

Science.gov (United States)

Wang, Zhi-Gang

2018-04-01

In this article, we assign the Z_c^± (3900) to be the diquark-antidiquark type axialvector tetraquark state, study its magnetic moment with the QCD sum rules in the external weak electromagnetic field by carrying out the operator product expansion up to the vacuum condensates of dimension 8. We pay special attention to matching the hadron side with the QCD side of the correlation function to obtain solid duality, the routine can be applied to study other electromagnetic properties of the exotic particles.

NNLO QCD analysis of CCFR data on xF3 structure function and Gross-Llewellyn Smith sum rule with higher twist and nuclear corrections

International Nuclear Information System (INIS)

Sidorov, A.V.; Tokarev, M.V.

1997-01-01

A detailed NNLO QCD analysis of new CCFR data on xF 3 structure function including the target mass, higher twist and nuclear corrections was performed and parametrizations of the perturbative and power terms of the structure function were constructed. The results of QCD analysis of the structure function were used to study the Q 2 -dependence of the Gross-Llewellyn Smith sum rule. The α S /π-expansion of S GLS (Q 2 ) was studied and parameters of the expansion were found to be s 1 =2.74±0.01, s 2 =-2.22±0.23, s 3 =-7.86±1.74 which are in good agreement with the perturbative QCD predictions for the Gross-Llewellyn Smith sum rule in the next-to-leading and next-to-next-to-leading order

Medium modifications of mesons. Chiral symmetry restoration, in-medium QCD sum rules for D and ρ mesons, and Bethe-Salpeter equations

Energy Technology Data Exchange (ETDEWEB)

Hilger, Thomas Uwe

2012-04-11

The interplay of hadron properties and their modification in an ambient nuclear medium on the one hand and spontaneous chiral symmetry breaking and its restoration on the other hand is investigated. QCD sum rules for D and B mesons embedded in cold nuclear matter are evaluated. We quantify the mass splitting of D- anti D and B- anti B mesons as a function of the nuclear matter density and investigate the impact of various condensates in linear density approximation. The analysis also includes D{sub s} and D{sup *}{sub 0} mesons. QCD sum rules for chiral partners in the open-charm meson sector are presented at nonzero baryon net density or temperature. We focus on the differences between pseudo-scalar and scalar as well as vector and axial-vector D mesons and derive the corresponding Weinberg type sum rules. Based on QCD sum rules we explore the consequences of a scenario for the ρ meson, where the chiral symmetry breaking condensates are set to zero whereas the chirally symmetric condensates remain at their vacuum values. The complementarity of mass shift and broadening is discussed. An alternative approach which utilizes coupled Dyson-Schwinger and Bethe-Salpeter equations for quark-antiquark bound states is investigated. For this purpose we analyze the analytic structure of the quark propagators in the complex plane numerically and test the possibility to widen the applicability of the method to the sector of heavy-light mesons in the scalar and pseudo-scalar channels, such as the D mesons, by varying the momentum partitioning parameter. The solutions of the Dyson-Schwinger equation in the Wigner-Weyl phase of chiral symmetry at nonzero bare quark masses are used to investigate a scenario with explicit but without dynamical chiral symmetry breaking.

Analysis of the scalar, axialvector, vector, tensor doubly charmed tetraquark states with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang; Yan, Ze-Hui [North China Electric Power University, Department of Physics, Baoding (China)

2018-01-15

In this article, we construct the axialvector-diquark-axialvector-antidiquark type currents to interpolate the scalar, axialvector, vector, tensor doubly charmed tetraquark states, and study them with QCD sum rules systematically by carrying out the operator product expansion up to the vacuum condensates of dimension 10 in a consistent way, the predicted masses can be confronted with the experimental data in the future. We can search for those doubly charmed tetraquark states in the Okubo-Zweig-Iizuka super-allowed strong decays to the charmed-meson pairs. (orig.)

QCD sum rule approach to the s→dγ contribution to the Ω-→Ξ-γ radiative decay

International Nuclear Information System (INIS)

Nielsen, M.; Barreiro, L.A.; Escobar, C.O.; Rosenfeld, R.

1996-01-01

QCD sum rules are used to calculate the contribution of the short-distance single-quark transition s→dγ to the amplitudes of the hyperon radiative decay Ω - →Ξ - γ. We reevaluate the Wilson coefficient of the effective operator responsible for this transition. We obtain a branching ratio which is comparable to the unitarity limit. copyright 1996 The American Physical Society

QCD sum rules for the gluon component of the U(1)sub(A) pseudoscalar meson

International Nuclear Information System (INIS)

Narison, S.; Centre National de la Recherche Scientifique, 13 - Marseille

1981-01-01

Using sum rules based on the positivity and the analyticity of the U(1)sub(A) spectral functions, and within the framework of QCD (quantum chromodynamics), we derive an upper bound Msub(p) approximately less than (0.6 approximately 0.75) GeV to the gluon component of the U(1)sub(A) meson mass. Such a bound could be identified as the exact value of Msub(p) if one accepts a QCD model for the ''continuum'' contribution to the U(1)sub(A) spectral functions. Comparing our result to the observed mass Msub(eta)' approximately equal to 0.96GeV, one could expect an important gluonic contribution to the eta'-mass. This experimental result could be reproduced, if one adds to our result, the quark contribution known to be Msub(q) approximately equal to root(3)msub(π). (author)

Status of the B0(S)-bar {B}0(S) Mixing from QCD Spectral Sum Rules

Science.gov (United States)

Narison, Stephan

2002-07-01

In this talk, I summarize new results 1 obtained from QCD spectral sum rules (QSSR), on the bag constant parameters entering in the analysis of the B0(s)-bar {B}0(s) mass-differences. Taking the average of the results from the Laplace and moment sum rules, one obtains to order α s: fB√ {hat {B}_B} ˜= (229 ± 55) GeV, fB{s}√ {BB_{s}}/f_B√ {BB} ˜= 1.18 ± 0.03, in units where fπ = 130.7 MeV. Combined with the experimental data on the mass-differences ΔMd,s, one obtains the constraint on the CKM weak mixing angle: |Vts/Vtd|2 ≥ 20.2(1.3). Alternatively, using the weak mixing angle from the analysis of the unitarity triangle and the data on ΔMd, one predicts ΔMs = 18.3(2.1) ps-1 in agreement with the present experimental lower bound and within the reach of Tevatron 2.

Gold-plated mode of CP-violation in decays of B{sub c} meson from QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Kiselev, V V [Russian State Research Center, ' Institute for High Energy Physics' , Protvino, Moscow Region, 142281 (Russian Federation)

2004-10-01

A model-independent method based on the triangle ideology is implemented to extract the CKM-matrix angle {gamma} in the decays of the doubly heavy long-lived meson B{sub c}. We analyse a colour structure of diagrams and conditions to reconstruct two reference triangles by tagging the flavour and CP eigenstates of D{sup 0} - D{sup 0}bar mesons in the fixed exclusive channels. The characteristic branching ratios are evaluated in the framework of QCD sum rules.

NNLO QCD analysis of CCFR data on xF3 structure function and Gross-Llewellyn-Smith sum rule with higher twist and nuclear corrections

International Nuclear Information System (INIS)

Sidorov, A.V.; Tokarev, M.V.

1997-01-01

A detailed NNLO QCD analysis of new CCFR data on xF 3 structure function including the target mass, higher twist and nuclear corrections was performed and parametrizations of the perturbative and power terms of the structure function were constructed. The results of QDC analysis of the structure function were used to study the Q 2 -dependence of the Gross-Llewellyn-Smith sum rule. The α s /π-expansion of S GLS (Q 2 ) was studied and parameters of the expansion were found to be s 1 =2.74±0.01, s 2 =-2.22±0.23, s 3 =-7.86±1.74 which are in good agreement with the perturbative QCD predictions for the Gross-Llewellyn-Smith sum rule in the next-to-leading and next-to-next-leading order

Pion form factor in QCD sum rules, local duality approach, and O(A2) fractional analytic perturbation theory

International Nuclear Information System (INIS)

Bakulev, Alexander P.

2010-01-01

Using the results on the electromagnetic pion Form Factor (FF) obtained in the O(α s ) QCD sum rules with non-local condensates [A.P. Bakulev, A.V. Pimikov, and N.G. Stefanis, Phys. Rev. D79 (2009) 093010] we determine the effective continuum threshold for the local duality approach. Then we apply it to construct the O(α s 2 ) estimation of the pion FF in the framework of the fractional analytic perturbation theory.

Analysis of the mass and width of the X*(3860) with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang [North China Electric Power University, Department of Physics, Baoding (China)

2017-10-15

In this article, we tentatively assign the X*(3860) to be the Cγ{sub 5} x γ{sub 5}C-type scalar tetraquark state and study its mass and width with the QCD sum rules; special attention is paid to calculating the hadronic coupling constants G{sub Xη{sub cπ}} and G{sub XDD} concerning the tetraquark state. We obtain the values M{sub X} = 3.86 ± 0.09 GeV and Γ{sub X} = 202 ± 146 MeV, which are consistent with the experimental data. The numerical result supports assigning the X*(3860) to be the Cγ{sub 5} x γ{sub 5}C-type scalar tetraquark state. (orig.)

QCD sum rule study of hidden-charm pentaquarks

Energy Technology Data Exchange (ETDEWEB)

Chen, Hua-Xing; Cui, Er-Liang [Beihang University, School of Physics and Beijing Key Laboratory of Advanced Nuclear Materials and Physics, Beijing (China); Chen, Wei; Steele, T.G. [University of Saskatchewan, Department of Physics and Engineering Physics, Saskatoon, Saskatchewan (Canada); Liu, Xiang [Lanzhou University, School of Physical Science and Technology, Lanzhou (China); Lanzhou University and Institute of Modern Physics of CAS, Research Center for Hadron and CSR Physics, Lanzhou (China); Zhu, Shi-Lin [Peking University, School of Physics and State Key Laboratory of Nuclear Physics and Technology, Beijing (China); Collaborative Innovation Center of Quantum Matter, Beijing (China); Peking University, Center of High Energy Physics, Beijing (China)

2016-10-15

We study the mass spectra of hidden-charm pentaquarks having spin J = (1)/(2)/(3)/(2)/(5)/(2) and quark contents uudc anti c. We systematically construct all the relevant local hidden-charm pentaquark currents, and we select some of them to perform QCD sum rule analyses. We find that the P{sub c}(4380) and P{sub c}(4450) can be identified as hidden-charm pentaquark states composed of an anti-charmed meson and a charmed baryon. Besides them, we also find (a) the lowest-lying hidden-charm pentaquark state of J{sup P} = 1/2{sup -} has the mass 4.33{sup +0.17}{sub -0.13} GeV, while the one of J{sup P} = 1/2{sup +} is significantly higher, that is, around 4.7-4.9 GeV; (b) the lowest-lying hidden-charm pentaquark state of J{sup P} = 3/2{sup -} has the mass 4.37{sup +0.18}{sub -0.13} GeV, consistent with the P{sub c}(4380) of J{sup P} = 3/2{sup -}, while the one of J{sup P} = 3/2{sup +} is also significantly higher, that is, above 4.6 GeV; (c) the hidden-charm pentaquark state of J{sup P} = 5/2{sup -} has a mass around 4.5-4.6 GeV, slightly larger than the P{sub c}(4450) of J{sup P} = 5/2{sup +}. (orig.)

Masses and decay constants of bound states containing fourth family quarks from QCD sum rules

International Nuclear Information System (INIS)

Bashiry, V.; Azizi, K.; Sultansoy, S.

2011-01-01

The heavy fourth generation of quarks that have sufficiently small mixing with the three known standard model families form hadrons. In the present work, we calculate the masses and decay constants of mesons containing either both quarks from the fourth generation or one from the fourth family and the other from known third family standard model quarks in the framework of the QCD sum rules. In the calculations, we take into account two-gluon condensate diagrams as nonperturbative contributions. The obtained results reduce to the known masses and decay constants of the bb and cc quarkonia when the fourth family quark is replaced by the bottom or charm quark.

Chiral corrections to the Adler-Weisberger sum rule

Science.gov (United States)

Beane, Silas R.; Klco, Natalie

2016-12-01

The Adler-Weisberger sum rule for the nucleon axial-vector charge, gA , offers a unique signature of chiral symmetry and its breaking in QCD. Its derivation relies on both algebraic aspects of chiral symmetry, which guarantee the convergence of the sum rule, and dynamical aspects of chiral symmetry breaking—as exploited using chiral perturbation theory—which allow the rigorous inclusion of explicit chiral symmetry breaking effects due to light-quark masses. The original derivations obtained the sum rule in the chiral limit and, without the benefit of chiral perturbation theory, made various attempts at extrapolating to nonvanishing pion masses. In this paper, the leading, universal, chiral corrections to the chiral-limit sum rule are obtained. Using PDG data, a recent parametrization of the pion-nucleon total cross sections in the resonance region given by the SAID group, as well as recent Roy-Steiner equation determinations of subthreshold amplitudes, threshold parameters, and correlated low-energy constants, the Adler-Weisberger sum rule is confronted with experimental data. With uncertainty estimates associated with the cross-section parametrization, the Goldberger-Treimann discrepancy, and the truncation of the sum rule at O (Mπ4) in the chiral expansion, this work finds gA=1.248 ±0.010 ±0.007 ±0.013 .

ρ, ω, and φ meson-nucleon scattering lengths from QCD sum rules

International Nuclear Information System (INIS)

Koike, Y.

1995-01-01

The QCD sum rule method is applied to derive a formula for the ρ, ω, and φ meson-nucleon spin-isospin--averaged scattering lengths a ρ,ω,φ . We found that the crucial matrix elements are left-angle bar qγ μ D ν q right-angle N (q=ud) (twist-2 nucleon matrix element) for a ρ,ω and m s left-angle bar ss right-angle N for a φ , and obtained a ρ =0.14±0.07 fm, a ω =0.11±0.06 fm, and a φ =0.035±0.020 fm. These small numbers originate from a common factor 1/(m N +m ρ,ω,φ ). Our result suggests a slight increase (<60 MeV for ρ and ω, and <15 MeV for φ) of the effective mass of these vector mesons in nuclear matter (in the dilute nucleon-gas approximation). The origin of the discrepancy with Hatsuda-Lee was clarified

Infrared renormalons and the relations between the Gross-Llewellyn Smith and the Bjorken polarized and unpolarized sum rules

International Nuclear Information System (INIS)

Kataev, A.L.

2005-01-01

It is demonstrated that the infrared renormalon calculus indicates that the QCD theoretical expressions for the Gross-Llewellyn Smith sum rule and for the Bjorken polarized and unpolarized ones contain an identical negative twist-4 1/Q 2 correction. This observation is supported by the consideration of the results of calculations of the corresponding twist-4 matrix elements. Together with the indication of the similarity of perturbative QCD contributions to these three sum rules, this observation leads to simple new theoretical relations between the Gross-Llewellyn Smith and Bjorken polarized and unpolarized sum rules in the energy region Q 2 ≥ 1 GeV 2 . The validity of this relation is checked using concrete experimental data for the Gross-Llewellyn Smith and Bjorken polarized sum rules [ru

Higher-twist effects in the B → π transition form factor from QCD light-cone sum rules

Energy Technology Data Exchange (ETDEWEB)

Khodjamirian, Alexander; Rusov, Aleksey [Universitaet Siegen (Germany). Fakultaet IV, Department Physik, Theoretische Physik 1 Walter-Flex-Strasse 3 57068 Siegen

2016-07-01

I report on the progress in calculating new higher-twist corrections to the QCD light-cone sum rule for the B → π transition form factor. First, the expansion of the massive heavy-quark propagator in the external gluonic field near the light-cone was extended to include new terms containing the gluon-field strength derivatives. The resulting analytical expressions for the twist-5 and twist-6 contributions to the correlation function were obtained in a factorized approximation, expressed via the product of the quark-condensate density and the lower-twist pion distribution amplitudes. The numerical analysis of new higher-twist effects is in progress.

Analysis of J/psi → etasub(c)γ decay by the method of QCD sum rules

International Nuclear Information System (INIS)

Bejlin, V.A.; Radyushkin, A.V.

1984-01-01

The radiative M1 transitions in charmonium are analyzed by the method of QCD sum rules taking into account nonperturbative corrections O( ). The dependence of the result on the choice of the parameter is investigated. The account of the lower nonperturbative corrections to the amplitude, describing radiation M1-transitions in charmonium, changes slightly the result for the decay widths GITA(J/psi → etasub(c)γ). The calculations show that the values of parameter phi, somewhat larger than the standard, one, result in shifting the theoretical values for GITA(J/psi → etasub(c)γ) in the direction of the experimental one, however no unambiguous conclusion on phi deviation of the standard value can be drawn without account for the contribution from higher dimensions

Analysis of the strong decays Ds3*(2860) → DK, D*K with QCD sum rules

International Nuclear Information System (INIS)

Wang, Zhi-Gang

2016-01-01

In this article, we assign the D s3 * (2860) to be a D-wave c anti s meson, study the hadronic coupling constants G D s3 * (2860)DK and G D s3 * (2860)D * K with the three-point QCD sum rules, and calculate the partial decay widths Γ(D s3 * (2860) → D * K) and Γ(D s3 * (2860) → DK). The predicted ratio R = Γ(D s3 * (2860) → D * K)/Γ(D s3 * (2860) → DK) = 0.57±0.38 cannot reproduce the experimental value R = Br(D sJ * (2860) → D * K)/Br(D sJ * (2860) → DK) = 1.10±0.15±0.19. (orig.)

Revisit assignments of the new excited Ω{sub c} states with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang; Wei, Xing-Ning; Yan, Ze-Hui [North China Electric Power University, Department of Physics, Baoding (China)

2017-12-15

In this article, we distinguish the contributions of the positive parity and negative parity Ω{sub c} states, study the masses and pole residues of the 1S, 1P, 2S and 2P Ω{sub c} states with the spin J = (1)/(2) and (3)/(2) using the QCD sum rules in a consistent way, and we revisit the assignments of the new narrow excited Ω{sub c}{sup 0} states. The predictions support assigning Ω{sub c}(3000) to the 1P Ω{sub c} state with J{sup P} = (1)/(2){sup -}, assigning Ω{sub c}(3090) to the 1P Ω{sub c} state with J{sup P} = (3)/(2){sup -} or the 2S Ω{sub c} state with J{sup P} = (1)/(2){sup +}, and assigning Ω{sub c}(3119) to the 2S Ω{sub c} state with J{sup P} = (3)/(2){sup +}. (orig.)

Analysis of the QQ anti Q anti Q tetraquark states with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang [North China Electric Power University, Department of Physics, Baoding (China)

2017-07-15

In this article, we study the J{sup PC} = 0{sup ++} and 2{sup ++} QQ anti Q anti Q tetraquark states with the QCD sum rules, and we obtain the predictions M{sub X(cc} {sub anti} {sub c} {sub anti} {sub c,0}{sup {sub +}{sub +)}} =5.99 ± 0.08 GeV, M{sub X(cc} {sub anti} {sub c} {sub anti} {sub c,2}{sup {sub +}{sub +)}} = 6.09 ± 0.08 GeV, M{sub X(bb} {sub anti} {sub b} {sub anti} {sub b,0}{sup {sub +}{sub +)}} = 18.84 ± 0.09 GeV and M{sub X(bb} {sub anti} {sub b} {sub anti} {sub b,2}{sup {sub +}{sub +)}} = 18.85 ± 0.09 GeV, which can be confronted to the experimental data in the future. Furthermore, we illustrate that the diquark-antidiquark type tetraquark state can be taken as a special superposition of a series of meson-meson pairs and that it embodies the net effects. (orig.)

Analysis of the strong decays Ds3 *(2860) → DK, D*K with QCD sum rules

Science.gov (United States)

Wang, Zhi-Gang

2016-10-01

In this article, we assign the D_{s3}^{ast}(2860) to be a D-wave c bar{s} meson, study the hadronic coupling constants G_{D_{s3}^{ast}(2860)DK} and G_{D_{s3}^{ast} (2860)D^{ast}K} with the three-point QCD sum rules, and calculate the partial decay widths Γ (D_{s3}^{ast} (2860) → D^{ast}K) and Γ (D_{s3}^{ast}(2860) → DK) . The predicted ratio R = Γ (D_{s3}^{ast} (2860)→ D^{ast}K)/Γ (D_{s3}^{ast} (2860)→ DK) = 0.57± 0.38 cannot reproduce the experimental value R = Br(D_{sJ}^{ast} (2860)→ D^{ast}K)/Br (D_{sJ}^{ast} (2860)→ DK) = 1.10 ± 0.15 ± 0.19.

The Zb(10610) and Zb(10650) as axial-vector tetraquark states in the QCD sum rules

International Nuclear Information System (INIS)

Wang, Zhi-Gang; Huang, Tao

2014-01-01

In this article, we study the axial-vector mesons Z b (10610) and Z b (10650) with the Cγ μ –Cγ 5 type and Cγ μ –Cγ ν type interpolating currents, respectively, by carrying out the operator product expansion to the vacuum condensates up to dimension 10. In calculations, we explore the energy scale dependence of the QCD spectral densities of the hidden bottom tetraquark states in detail for the first time, and suggest a formula μ=√(M X/Y/Z 2 −(2M b ) 2 ) with the effective mass M b =5.13 GeV to determine the energy scales. The numerical results favor assigning the Z b (10610) and Z b (10650) as the Cγ μ –Cγ 5 type and Cγ μ –Cγ ν type hidden bottom tetraquark states, respectively. We obtain the mass of the J PC =1 ++ hidden bottom tetraquark state as a byproduct, which can be compared to the experimental data in the futures. Furthermore, we study the strong decays Z b ± (10610)→ϒπ ± ,η b ρ ± with the three-point QCD sum rules, the decay widths also support assigning the Z b (10610) as the Cγ μ –Cγ 5 type hidden bottom tetraquark state

QCD sum rules of the Laplace transform type for the gluon component of the U(1)sub(A) meson mass

International Nuclear Information System (INIS)

Narison, S.

1981-07-01

We get upper bound of the gluon component of the U(1)sub(A) meson mass using QCD sum rules of the Laplace transform type to the two-point functions associated to the divergence of the U(1)sub(A) current in the chiral limit. For Λ is approximately equal to 70 is approximately 210 MeV and fsub(eta') is approximately equal to (0.5 is approximately 0.7) sqrt 3 fsub(π), we obtain Msub(G) is approximately smaller to (0.6 is approximately 0.85) GeV, which indicates an important gluon contribution to the eta' mass. (author)

Electronuclear sum rules

International Nuclear Information System (INIS)

Arenhoevel, H.; Drechsel, D.; Weber, H.J.

1978-01-01

Generalized sum rules are derived by integrating the electromagnetic structure functions along lines of constant ratio of momentum and energy transfer. For non-relativistic systems these sum rules are related to the conventional photonuclear sum rules by a scaling transformation. The generalized sum rules are connected with the absorptive part of the forward scattering amplitude of virtual photons. The analytic structure of the scattering amplitudes and the possible existence of dispersion relations have been investigated in schematic relativistic and non-relativistic models. While for the non-relativistic case analyticity does not hold, the relativistic scattering amplitude is analytical for time-like (but not for space-like) photons and relations similar to the Gell-Mann-Goldberger-Thirring sum rule exist. (Auth.)

QCD sum rules study of the JPC=1-- charmonium Y mesons

International Nuclear Information System (INIS)

Albuquerque, R.M.; Nielsen, M.

2009-01-01

We use QCD sum rules to test the nature of the recently observed mesons Y(4260), Y(4350) and Y(4660), assumed to be exotic four-quark (cc-bar qq-bar) or (cc-bar ss-bar) states with J PC =1 -- . We work at leading order in α s , consider the contributions of higher dimension condensates and keep terms which are linear in the strange quark mass m s . We find for the (cc-bar ss-bar) state a mass m Y =(4.65±0.10) GeV which is compatible with the experimental candidate Y(4660), while for the (cc-bar qq-bar) state we find a mass m Y =(4.49±0.11) GeV, which is still consistent with the mass of the experimental candidate Y(4350). With the tetraquark structure we are working we cannot explain the Y(4260) as a tetraquark state. We also consider molecular D s0 D-bar s * and D 0 D-bar * states. For the D s0 D-bar s * molecular state we get m D s0 D -bar s* =(4.42±0.10) GeV which is consistent, considering the errors, with the mass of the meson Y(4350) and for the D 0 D-bar* molecular state we get m D 0 D -bar*=(4.27±0.10) GeV in excellent agreement with the mass of the meson Y(4260)

The polarised photon g1γ sum rule at the linear collider and high luminosity B factories

International Nuclear Information System (INIS)

Shore, G.M.

2005-01-01

The sum rule for the first moment of the polarised (virtual) photon structure function g 1 γ (x,Q 2 ;K 2 ) is revisited in the light of proposals for future e + e - colliders. The sum rule exhibits an array of phenomena characteristic of QCD: for real photons (K 2 =0) electromagnetic gauge invariance constrains the first moment to vanish; the limit for asymptotic photon virtuality (m ρ 2 -bar K 2 -bar Q 2 ) is governed by the electromagnetic U A (1) axial anomaly and the approach to asymptopia by the gluonic anomaly; for intermediate values of K 2 , it reflects the realisation of chiral symmetry and is determined by the off-shell radiative couplings of the pseudoscalar mesons; finally, like many polarisation phenomena in QCD, the first moment of g 1 γ involves the gluon topological susceptibility. In this paper, we review the original sum rule proposed by Narison, Shore and Veneziano and extend the relation with pseudoscalar mesons. The possibility of measuring the sum rule in future polarised e + e - colliders is then considered in detail, focusing on the International Linear Collider (ILC) and high luminosity B factories. We conclude that all the above features of the sum rule should be accessible at a polarised collider with the characteristics of SuperKEKB

Quantum chromodynamical calculations of meson wave functions in the light-cone formalism by means of QCD sum rules

International Nuclear Information System (INIS)

Guellenstern, S.

1991-09-01

Using the technique of Cherniak and Zhitnitzky we have calculated the wavefunctions of ρ(770) and Φ(1020) within the framework of QCD sum rules. Whereas the standard approach assumes light-like distances of the quarks (z 2 = 0), we also have taken into account higher order terms in z 2 . Thus, we obtained non-vanishing orbital angular momentum contributions. The first few moments of various invariant functions have been calculated with the help of an especially developed REDUCE program package. In zeroth order (z 2 = 0) our results of the reconstructed wavefunctions agree with those in the literature. However, we got first order contributions in z 2 of an amount of almost 10% of the corresponding zeroth order. (orig.)

Local-duality QCD sum rules for strong isospin breaking in the decay constants of heavy-light mesons

Energy Technology Data Exchange (ETDEWEB)

Lucha, Wolfgang [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); Melikhov, Dmitri [Austrian Academy of Sciences, Institute for High Energy Physics, Vienna (Austria); M.V. Lomonosov Moscow State University, D.V. Skobeltsyn Institute of Nuclear Physics, Moscow (Russian Federation); University of Vienna, Faculty of Physics, Vienna (Austria); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Rome (Italy)

2018-02-15

We discuss the leptonic decay constants of heavy-light mesons by means of Borel QCD sum rules in the local-duality (LD) limit of infinitely large Borel mass parameter. In this limit, for an appropriate choice of the invariant structures in the QCD correlation functions, all vacuum-condensate contributions vanish and all nonperturbative effects are contained in only one quantity, the effective threshold. We study properties of the LD effective thresholds in the limits of large heavy-quark mass m{sub Q} and small light-quark mass m{sub q}. In the heavy-quark limit, we clarify the role played by the radiative corrections in the effective threshold for reproducing the pQCD expansion of the decay constants of pseudoscalar and vector mesons. We show that the dependence of the meson decay constants on m{sub q} arises predominantly (at the level of 70-80%) from the calculable m{sub q}-dependence of the perturbative spectral densities. Making use of the lattice QCD results for the decay constants of nonstrange and strange pseudoscalar and vector heavy mesons, we obtain solid predictions for the decay constants of heavy-light mesons as functions of m{sub q} in the range from a few to 100 MeV and evaluate the corresponding strong isospin-breaking effects: f{sub D{sup +}} - f{sub D{sup 0}} = (0.96 ± 0.09) MeV, f{sub D}{sup {sub *}{sub +}} - f{sub D}{sup {sub *}{sub 0}} = (1.18 ± 0.35) MeV, f{sub B{sup 0}} - f{sub B{sup +}} = (1.01 ± 0.10) MeV, f{sub B}{sup {sub *}{sub 0}} - f{sub B}{sup {sub *}{sub +}} = (0.89 ± 0.30) MeV. (orig.)

The nucleon axial isoscalar coupling constant and the Bjorken sum rule

International Nuclear Information System (INIS)

Belyaev, V.M.; Ioffe, B.L.; Kogan, Ya.I.

1984-01-01

The nucleon coupling constant with the axial isoscalar current entering the Bjorken sum rule for the deep inelastic scattering of polarized electrons on a polarized target is calculated in nonperturbative QCD. The result, gsub(A)sup(s) approximately 0.5, is about a factor of two smaller as compared to that of the SU(6) symmetric quark model

Estimating the small-x exponent of the structure function g1NS from the Bjorken sum rule

International Nuclear Information System (INIS)

Knauf, Anke; Meyer-Hermann, Michael; Soff, Gerhard

2002-01-01

We present a new estimate of the exponent governing the small-x behavior of the nonsinglet structure function g 1 p-n derived under the assumption that the Bjorken sum rule is valid. We use the world wide average of α s and the NNNLO QCD corrections to the Bjorken sum rule. The structure function g 1 NS is found to be clearly divergent for small x

Evaluating chiral symmetry restoration through the use of sum rules

Directory of Open Access Journals (Sweden)

Rapp Ralf

2012-11-01

Full Text Available We pursue the idea of assessing chiral restoration via in-medium modifications of hadronic spectral functions of chiral partners. The usefulness of sum rules in this endeavor is illustrated, focusing on the vector/axial-vector channel. We first present an update on obtaining quantitative results for pertinent vacuum spectral functions. These serve as a basis upon which the in-medium spectral functions can be constructed. A novel feature of our analysis of the vacuum spectral functions is the need to include excited resonances, dictated by satisfying the Weinberg-type sum rules. This includes excited states in both the vector and axial-vector channels.We also analyze the QCD sum rule for the finite temperature vector spectral function, based on a ρ spectral function tested in dilepton data which develops a shoulder at low energies.We find that the ρ′ peak flattens off which may be a sign of chiral restoration, though a study of the finite temperature axial-vector spectral function remains to be carried out.

Relativistic and Nuclear Medium Effects on the Coulomb Sum Rule.

Science.gov (United States)

Cloët, Ian C; Bentz, Wolfgang; Thomas, Anthony W

2016-01-22

In light of the forthcoming high precision quasielastic electron scattering data from Jefferson Lab, it is timely for the various approaches to nuclear structure to make robust predictions for the associated response functions. With this in mind, we focus here on the longitudinal response function and the corresponding Coulomb sum rule for isospin-symmetric nuclear matter at various baryon densities. Using a quantum field-theoretic quark-level approach which preserves the symmetries of quantum chromodynamics, as well as exhibiting dynamical chiral symmetry breaking and quark confinement, we find a dramatic quenching of the Coulomb sum rule for momentum transfers |q|≳0.5  GeV. The main driver of this effect lies in changes to the proton Dirac form factor induced by the nuclear medium. Such a dramatic quenching of the Coulomb sum rule was not seen in a recent quantum Monte Carlo calculation for carbon, suggesting that the Jefferson Lab data may well shed new light on the explicit role of QCD in nuclei.

Calculation of excited vector meson electron widths using QCD sum rules

International Nuclear Information System (INIS)

Geshkenbein, B.V.

1984-01-01

The sum rules are suggested which allow one to calculate the electron widths of excited vector mesons of the PSI, UPSILON, rho meson family assuming the values of their masses to be known. The calculated values of the electron widths agree with experiment

Reanalysis of the Y(3940), Y(4140), Zc(4020), Zc(4025), and Zb(10650) as molecular states with QCD sum rules

International Nuclear Information System (INIS)

Wang, Zhi-Gang

2014-01-01

In this article, we calculate the contributions of the vacuum condensates up to dimension 10 in the operator product expansion, and study the J PC = 0 ++ , 1 +- , 2 ++ D * anti D * , D s * anti D s * , B * anti B * , B s * anti B s * molecular states with the QCD sum rules. In the calculations, we use the formula μ = √(M 2 X/Y/Z -(2M Q ) 2 ) to determine the energy scales of the QCD spectral densities. The numerical results favor assigning the Z c (4020) and Z c (4025) to the J PC = 0 ++ , 1 +- or 2 ++ D * anti D * molecular states, the Y(4140) to the J PC = 0 ++ D s * anti D s * molecular state, the Z b (10650) to the J PC = 1 +- B * anti B * molecular state, and they disfavor assigning the Y(3940) to the (J PC = 0 ++ ) molecular state. The present predictions can be confronted with the experimental data in the future. (orig.)

Analysis of the strong coupling form factors of ΣbNB and ΣcND in QCD sum rules

Science.gov (United States)

Yu, Guo-Liang; Wang, Zhi-Gang; Li, Zhen-Yu

2017-08-01

In this article, we study the strong interaction of the vertices Σ b NB and Σ c ND using the three-point QCD sum rules under two different Dirac structures. Considering the contributions of the vacuum condensates up to dimension 5 in the operation product expansion, the form factors of these vertices are calculated. Then, we fit the form factors into analytical functions and extrapolate them into time-like regions, which gives the coupling constants. Our analysis indicates that the coupling constants for these two vertices are G ΣbNB = 0.43±0.01 GeV-1 and G ΣcND = 3.76±0.05 GeV-1. Supported by Fundamental Research Funds for the Central Universities (2016MS133)

Analysis of the strong decay X(5568) → B{sub s}{sup 0}π{sup +} with QCD sum rules

Energy Technology Data Exchange (ETDEWEB)

Wang, Zhi-Gang [North China Electric Power University, Department of Physics, Baoding (China)

2016-05-15

In this article, we take the X(5568) to be the scalar diquark-antidiquark type tetraquark state, study the hadronic coupling constant g{sub XB{sub sπ}} with the three-point QCD sum rules by carrying out the operator product expansion up to the vacuum condensates of dimension-6 and including both the connected and the disconnected Feynman diagrams; then we calculate the partial decay width of the strong decay X(5568) → B{sub s}{sup 0}π{sup +} and obtain the value Γ{sub X} = (20.5 ± 8.1) MeV, which is consistent with the experimental data Γ{sub X} = (21.9 ± 6.4{sup +5.0}{sub -2.5}) MeV from the D0 collaboration. (orig.)

Sum rules and exclusive processes in quantum chromodynamics

International Nuclear Information System (INIS)

Radyushkin, A.V.

1983-01-01

A brief review of results of analyzing hadron form factors is presented. The analysis of hardron form factors was conducted by the method of QCD sum rules. The method is based on the concept of quark-hadron duality. Correlation of calculation results with available experimental data was performed. The conclusion is made that it is sufficient to consider only the contribution of the simplest diagrams which don't contain gluon exchanges in order to describe experimental data on pion, proton and neutron form factors

0+ tetraquark states from improved QCD sum rules: delving into X(5568)

Science.gov (United States)

Zhang, Jian-Rong; Zou, Jing-Lan; Wu, Jin-Yun

2018-04-01

In order to investigate the possibility of the recently observed X(5568) being a 0+ tetraquark state, we make an improvement to the study of the related various configuration states in the framework of the QCD sum rules. Particularly, to ensure the quality of the analysis, condensates up to dimension 12 are included to inspect the convergence of operator product expansion (OPE) and improve the final results of the studied states. We note that some condensate contributions could play an important role on the OPE side. By releasing the rigid OPE convergence criterion, we arrive at the numerical value {5.57}-0.23+0.35 {{GeV}} for the scalar-scalar diquark-antidiquark 0+ state, which agrees with the experimental data for the X(5568) and could support its interpretation in terms of a 0+ tetraquark state with the scalar-scalar configuration. The corresponding result for the axial-axial current is calculated to be {5.77}-0.33+0.44 {{GeV}}, which is still consistent with the mass of X(5568) in view of the uncertainty. The feasibility of X(5568) being a tetraquark state with the axial-axial configuration therefore cannot be definitely excluded. For the pseudoscalar-pseudoscalar and the vector-vector cases, their unsatisfactory OPE convergence make it difficult to find reasonable work windows to extract the hadronic information. Supported by National Natural Science Foundation of China (11475258, 11105223, 11675263) and the Project in NUDT for Excellent Youth Talents

Q2 evolution of generalized Baldin sum rule for the proton

International Nuclear Information System (INIS)

Liang, Y.; Christy, M. E.; Ent, R.; Keppel, C. E.

2006-01-01

The generalized Baldin sum rule for virtual photon scattering, the unpolarized analogy of the generalized Gerasimov-Drell-Hearn integral provides an important way to investigate the transition between perturbative QCD and hadronic descriptions of nucleon structure. This sum rule requires integration of the nucleon structure function F 1 , which until recently had not been measured at low Q 2 and large x, i.e., in the nucleon resonance region. This work uses new data from inclusive electron-proton scattering in the resonance region obtained at Jefferson Lab, in combination with SLAC deep inelastic scattering data, to present first precision measurements of the generalized Baldin integral for the proton in the Q 2 range of 0.3 to 4.0 GeV 2

Method of analytic continuation by duality in QCD: Beyond QCD sum rules

International Nuclear Information System (INIS)

Kremer, M.; Nasrallah, N.F.; Papadopoulos, N.A.; Schilcher, K.

1986-01-01

We present the method of analytic continuation by duality which allows the approximate continuation of QCD amplitudes to small values of the momentum variables where direct perturbative calculations are not possible. This allows a substantial extension of the domain of applications of hadronic QCD phenomenology. The method is illustrated by a simple example which shows its essential features

Experimental status QCD

International Nuclear Information System (INIS)

Radyushkin, A.V.; Slepchenko, L.A.

1983-01-01

Analysis of experimental status of quantum chromodynamics (QCD) has been carried out. A short introduction into QCD is given. QCD sum rules are considered. Jets in e + e - annihilation and inclusive processes of lepton-hadron and hadron-hadron scattering are considered. Effect of QCD corrections to perturbation theory on quark count is analyzed

Quark-number susceptibility, thermodynamic sum rule, and the hard thermal loop approximation

International Nuclear Information System (INIS)

Chakraborty, Purnendu; Mustafa, Munshi G.; Thoma, Markus H.

2003-01-01

The quark number susceptibility, associated with the conserved quark number density, is closely related to the baryon and charge fluctuations in the quark-gluon plasma, which might serve as signature for the quark-gluon plasma formation in ultrarelativistic heavy-ion collisions. In addition to QCD lattice simulations, the quark number susceptibility has been calculated recently using a resummed perturbation theory (hard thermal loop resummation). In the present work we show, based on general arguments, that the computation of this quantity neglecting hard thermal loop vertices contradicts the Ward identity and violates the thermodynamic sum rule following from quark number conservation. We further show that the hard thermal loop perturbation theory is consistent with the thermodynamic sum rule

A sum rule approach to the violation of Dashen's theorem

International Nuclear Information System (INIS)

Moussallam, B.

1999-01-01

A classic sum rule by Das et al. is extended to seven of the low-energy constant K i , introduced by Urech, which parameterizes electromagnetic corrections at chiral order O(e 2 p 2 ). Using the spurion formalism, a simple convolution representation is shown to hold and the structure in terms of the chiral renormalization scale, QCD renormalization scale and the QED gauge parameter is displayed. The role of the resonances is studied as providing rational interpolants to relevant QCD n-point functions in the Euclidean domain. A variety of asymptotic constraints must be implemented which have phenomenological consequences. A current assumption concerning the dominance of the lowest-lying resonances is shown clearly to fail in some cases. (author)

The form factors of the process γ*γ*→π0 for small virtuality of one of the photons and QCD sum rules (1): the structure of the infrared singularities

International Nuclear Information System (INIS)

Radyushkin, A.V.; Ruskov, R.

1992-01-01

We extend the QCD sum rule analysis of the form factor F γ* γ *→π 0 (q 1 2 ,q 2 2 ) into the region of small virtuality of one of the photons, where one should perform more precisely an OPE to factorize large and small distance contributions. As a first step the form factor is investigated in the region of moderate virtualities and the full corrections in the sum rule are obtained. It is shown that the infrared mass singularities are subtracted in the corresponding OPE for essentially nonsymmetric kinematics due to the operators of lowest two twists. On a simple scalar example the most important steps of the further calculations are demonstrated. 26 refs.; 8 figs

QCD as a Theory of Hadrons

Science.gov (United States)

Narison, Stephan

2007-07-01

Spectral Sum Rules: 47. Introduction; 48. Theoretical foundations; 49. Survey of QCD spectral sum rules; 50. Weinberg and DMO sum rules; 51. The QCD coupling as; 52. The QCD condensates; 53. Light and heavy quark masses, etc.; 54. Hadron spectroscopy; 55. D, B and Bc exclusive weak decays; 56. B0(s)-B0(s) mixing, kaon CP violation; 57. Thermal behaviour of QCD; 58. More on spectral sum rules; Part XI. Appendix A: physical constants and unites; Appendix B: weight factors for SU(N)c; Appendix C: coordinates and momenta; Appendix D: Dirac equation and matrices; Appendix E: Feynman rules; Appendix F: Feynman integrals; Appendix G: useful formulae for the sum rules; Bibliography; Index.

The influence of gluonic operators on QCD sum rules for baryons

International Nuclear Information System (INIS)

Schall, D.

1982-01-01

In this thesis the operator product expansion (OPE) is extended up to operators of dimension d=10. The coefficient functions are calculated only up to order αsub(s). Thereby the performation of the OPE by means of the Schwinger operator formalism is extensively described. In the final section the sum rules for nucleon and delta are discussed. (orig./HSI) [de

Sum rules in classical scattering

International Nuclear Information System (INIS)

Bolle, D.; Osborn, T.A.

1981-01-01

This paper derives sum rules associated with the classical scattering of two particles. These sum rules are the analogs of Levinson's theorem in quantum mechanics which provides a relationship between the number of bound-state wavefunctions and the energy integral of the time delay of the scattering process. The associated classical relation is an identity involving classical time delay and an integral over the classical bound-state density. We show that equalities between the Nth-order energy moment of the classical time delay and the Nth-order energy moment of the classical bound-state density hold in both a local and a global form. Local sum rules involve the time delay defined on a finite but otherwise arbitrary coordinate space volume S and the bound-state density associated with this same region. Global sum rules are those that obtain when S is the whole coordinate space. Both the local and global sum rules are derived for potentials of arbitrary shape and for scattering in any space dimension. Finally the set of classical sum rules, together with the known quantum mechanical analogs, are shown to provide a unified method of obtaining the high-temperature expansion of the classical, respectively the quantum-mechanical, virial coefficients

On the twist-2 contributions to polarized structure functions and new sum rules

International Nuclear Information System (INIS)

Bluemlein, J.; Kochelev, N.

1996-03-01

The twist-2 contributions to the polarized structure functions in deep inelastic lepton-hadron scattering are calculated including the exchange of weak bosons and using both the operator product expansion and the covariant parton model. A new relation between two structure functions leading to a sequence of new sum rules is found. The light quark mass corrections to the structure functions are derived in lowest order QCD. (orig.)

Cosmic Sum Rules

DEFF Research Database (Denmark)

T. Frandsen, Mads; Masina, Isabella; Sannino, Francesco

2011-01-01

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models.......We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays and show how it can be used to predict the positron fraction at energies not yet explored by current experiments and to constrain specific models....

Estimates of md-mu and left-angle bar dd right-angle -left-angle bar uu right-angle from QCD sum rules for D and D* isospin mass differences

International Nuclear Information System (INIS)

Eletsky, V.L.; Ioffe, B.L.

1993-01-01

The recent experimental data on D +- D0 and D *+- D*0 mass differences are used as inputs in the QCD sum rules to obtain new estimates on the mass difference of light quarks and on the difference of their condensates: m d -m u =3±1 MeV, left-angle bar dd right-angle -left-angle bar uu right-angle=-(2.5±1)x10 -3 left-angle bar uu right-angle (at a standard normalization point, μ=0.5 GeV)

The Operator Product Expansion Beyond Perturbation Theory in QCD

International Nuclear Information System (INIS)

Dominguez, C. A.

2011-01-01

The Operator Product Expansion (OPE) of current correlators at short distances beyond perturbation theory in QCD, together with Cauchy's theorem in the complex energy plane, are the pillars of the method of QCD sum rules. This technique provides an analytic tool to relate QCD with hadronic physics at low and intermediate energies. It has been in use for over thirty years to determine hadronic parameters, form factors, and QCD parameters such as the quark masses, and the running strong coupling at the scale of the τ-lepton. QCD sum rules provide a powerful complement to numerical simulations of QCD on the lattice. In this talk a short review of the method is presented for non experts, followed by three examples of recent applications.

Behaviour at x = 0,1, sum rules and parametrizations for structure functions beyond the leading order

International Nuclear Information System (INIS)

Lopez, C.

1981-01-01

We write the simplest possible parametrizations of deep inelastic structure functions which satisfy the following requirements: (i) exact compatibility with QCD at the endpoints x = 0,1, to second order; (ii) fulfilment of sum rules to second order; (iii) leading and subleading Regge behaviour. In all we find that, including the QCD scale Λ, such parametrizations describe in a simple manner the three standard functions W 1 , W 2 , W 3 for all x, Q 2 in terms of four to six parameters only (two more if allowing for higher twists). (orig.)

Momentum sum rules for fragmentation functions

International Nuclear Information System (INIS)

Meissner, S.; Metz, A.; Pitonyak, D.

2010-01-01

Momentum sum rules for fragmentation functions are considered. In particular, we give a general proof of the Schaefer-Teryaev sum rule for the transverse momentum dependent Collins function. We also argue that corresponding sum rules for related fragmentation functions do not exist. Our model-independent analysis is supplemented by calculations in a simple field-theoretical model.

Current algebra sum rules for Reggeons

CERN Document Server

Carlitz, R

1972-01-01

The interplay between the constraints of chiral SU/sub 2/*SU/sub 2/ symmetry and Regge asymptotic behaviour is investigated. The author reviews the derivation of various current algebra sum rules in a study of the reaction pi + alpha to pi + beta . These sum rules imply that all particles may be classified in multiplets of SU/sub 2/*SU/sub 2/ and that each of these multiplets may contain linear combinations of an infinite number of physical states. Extending his study to the reaction pi + alpha to pi + pi + beta , he derives new sum rules involving commutators of the axial charge with the reggeon coupling matrices of the rho and f Regge trajectories. Some applications of these new sum rules are noted, and the general utility of these and related sum rules is discussed. (17 refs).

Transition form factors of π0,η and η′ mesons: What can be learned from anomaly sum rule?

International Nuclear Information System (INIS)

Klopot, Yaroslav; Oganesian, Armen; Teryaev, Oleg

2013-01-01

We studied the applications of the anomaly sum rule (ASR) to the transition form factors of light pseudoscalar mesons: π 0 ,η and η ′ . This nonperturbative QCD approach can be used even if the QCD factorization is broken. The status of possible small non-OPE corrections to continuum in comparison to BaBar and Belle data is explored. The accuracy of the applied method and the role of the quark mass contributions are discussed

Sum rules for collisional processes

International Nuclear Information System (INIS)

Oreg, J.; Goldstein, W.H.; Bar-Shalom, A.; Klapisch, M.

1991-01-01

We derive level-to-configuration sum rules for dielectronic capture and for collisional excitation and ionization. These sum rules give the total transition rate from a detailed atomic level to an atomic configuration. For each process, we show that it is possible to factor out the dependence on continuum-electron wave functions. The remaining explicit level dependence of each rate is then obtained from the matrix element of an effective operator acting on the bound orbitals only. In a large class of cases, the effective operator reduces to a one-electron monopole whose matrix element is proportional to the statistical weight of the level. We show that even in these cases, nonstatistical level dependence enters through the dependence of radial integrals on continuum orbitals. For each process, explicit analytic expressions for the level-to-configuration sum rules are given for all possible cases. Together with the well-known J-file sum rule for radiative rates [E. U. Condon and G. H. Shortley, The Theory of Atomic Spectra (University Press, Cambridge, 1935)], the sum rules offer a systematic and efficient procedure for collapsing high-multiplicity configurations into ''effective'' levels for the purpose of modeling the population kinetics of ionized heavy atoms in plasma

Quark content of the nucleon in QCD: Perturbative and nonperturbative aspects

International Nuclear Information System (INIS)

Stefanis, N.G.

1989-01-01

We elaborate on two proposed model distribution amplitudes for the nucleon, based on perturbative light-cone QCD supplemented by QCD sum rules. The novel nonperturbative features of these amplitudes are discussed in detail. Reasonable predictions for the Dirac form factor of the proton and the neutron are obtained, paying particular attention to the treatment of the effective coupling constant α s (Q 2 ) and the scale parameter Λ QCD . In addition, the stability properties of the sum rules for the moments of these model distribution amplitudes are analyzed. The range of values of the parameters entering the sum rules is estimated. Relying on expectation values of longitudinal-momentum fractions instead of moments, a heuristic interpretation of the physical content of the model distribution amplitudes is attempted

Robinson's radiation damping sum rule: Reaffirmation and extension

International Nuclear Information System (INIS)

Mane, S.R.

2011-01-01

Robinson's radiation damping sum rule is one of the classic theorems of accelerator physics. Recently Orlov has claimed to find serious flaws in Robinson's proof of his sum rule. In view of the importance of the subject, I have independently examined the derivation of the Robinson radiation damping sum rule. Orlov's criticisms are without merit: I work through Robinson's derivation and demonstrate that Orlov's criticisms violate well-established mathematical theorems and are hence not valid. I also show that Robinson's derivation, and his damping sum rule, is valid in a larger domain than that treated by Robinson himself: Robinson derived his sum rule under the approximation of a small damping rate, but I show that Robinson's sum rule applies to arbitrary damping rates. I also display more concise derivations of the sum rule using matrix differential equations. I also show that Robinson's sum rule is valid in the vicinity of a parametric resonance.

Model dependence of energy-weighted sum rules

International Nuclear Information System (INIS)

Kirson, M.W.

1977-01-01

The contribution of the nucleon-nucleon interaction to energy-weighted sum rules for electromagnetic multipole transitions is investigated. It is found that only isoscalar electric transitions might have model-independent energy-weighted sum rules. For these transitions, explicit momentum and angular momentum dependence of the nuclear force give rise to corrections to the sum rule which are found to be negligibly small, thus confirming the model independence of these specific sum rules. These conclusions are unaffected by correlation effects. (author)

Electronuclear sum rules for the lightest nuclei

International Nuclear Information System (INIS)

Efros, V.D.

1992-01-01

It is shown that the model-independent longitudinal electronuclear sum rules for nuclei with A = 3 and A = 4 have an accuracy on the order of a percent in the traditional single-nucleon approximation with free nucleons for the nuclear charge-density operator. This makes it possible to test this approximation by using these sum rules. The longitudinal sum rules for A = 3 and A = 4 are calculated using the wave functions of these nuclei corresponding to a large set of realistic NN interactions. The values of the model-independent sum rules lie in the range of values calculated by this method. Model-independent expressions are obtained for the transverse sum rules for nuclei with A = 3 and A = 4. These sum rules are calculated using a large set of realistic wave functions of these nuclei. The contribution of the convection current and the changes in the results for different versions of realistic NN forces are given. 29 refs., 4 tabs

Inverse-moment chiral sum rules

International Nuclear Information System (INIS)

Golowich, E.; Kambor, J.

1996-01-01

A general class of inverse-moment sum rules was previously derived by the authors in a chiral perturbation theory (ChPT) study at two-loop order of the isospin and hypercharge vector-current propagators. Here, we address the evaluation of the inverse-moment sum rules in terms of existing data and theoretical constraints. Two kinds of sum rules are seen to occur: those which contain as-yet undetermined O(q 6 ) counterterms and those free of such quantities. We use the former to obtain phenomenological evaluations of two O(q 6 ) counterterms. Light is shed on the important but difficult issue regarding contributions of higher orders in the ChPT expansion. copyright 1996 The American Physical Society

QCD: Renormalization for the practitioner

International Nuclear Information System (INIS)

Pascual, P.; Tarrach, R.

1984-01-01

These notes correspond to a GIFT (Grupo Interuniversitario de Fisica Teorica) course which was given by us in autumn 1983 at the University of Barcelona. Their main subject is renormalization in perturbative QCD and only the last chapter goes beyond perturbation theory. They are essentially self contained and their aim is to teach the student the techniques of perturbative QCD and the QCD sum rules. (orig./HSI)

B→ππ form factors from light-cone sum rules with B-meson distribution amplitudes

Energy Technology Data Exchange (ETDEWEB)

Cheng, Shan; Khodjamirian, Alexander [Theoretische Physik 1, Naturwissenschaftlich-Technische Fakultät,Department Physik, Universität Siegen,Walter-Flex-Strasse 3, 57068 Siegen (Germany); Virto, Javier [Albert Einstein Center for Fundamental Physics,Institute for Theoretical Physics, University of Bern,Sidlerstrasse 5, CH-3012 Bern (Switzerland)

2017-05-30

We study B→ππ form factors using QCD light-cone sum rules with B-meson distribution amplitudes. These form factors describe the semileptonic decay B→ππℓν̄{sub ℓ}, and constitute an essential input in B→ππℓ{sup +}ℓ{sup −} and B→πππ decays. We employ the correlation functions where a dipion isospin-one state is interpolated by the vector light-quark current. We obtain sum rules where convolutions of the P-wave B̄{sup 0}→π{sup +}π{sup 0} form factors with the timelike pion vector form factor are related to universal B-meson distribution amplitudes. These sum rules are valid in the kinematic regime where the dipion state has a large energy and a low invariant mass, and reproduce analytically the known light-cone sum rules for B→ρ form factors in the limit of ρ-dominance and zero width, thus providing a systematics for so far unaccounted corrections to B→ρ transitions. Using data for the pion vector form factor, we estimate finite-width effects and the contribution of excited ρ-resonances to the B→ππ form factors. We find that these contributions amount up to ∼20% in the small dipion mass region where they can be effectively regarded as a nonresonant (P-wave) background to the B→ρ transition.

Neutrino mass sum-rule

Science.gov (United States)

Damanik, Asan

2018-03-01

Neutrino mass sum-rele is a very important research subject from theoretical side because neutrino oscillation experiment only gave us two squared-mass differences and three mixing angles. We review neutrino mass sum-rule in literature that have been reported by many authors and discuss its phenomenological implications.

Sum rules in the response function method

International Nuclear Information System (INIS)

Takayanagi, Kazuo

1990-01-01

Sum rules in the response function method are studied in detail. A sum rule can be obtained theoretically by integrating the imaginary part of the response function over the excitation energy with a corresponding energy weight. Generally, the response function is calculated perturbatively in terms of the residual interaction, and the expansion can be described by diagrammatic methods. In this paper, we present a classification of the diagrams so as to clarify which diagram has what contribution to which sum rule. This will allow us to get insight into the contributions to the sum rules of all the processes expressed by Goldstone diagrams. (orig.)

Nonperturbation aspects of QCD. Monte Carlo and optimization

International Nuclear Information System (INIS)

Brezin, E.; Morel, A.; Marinari, E.; Couchot, F.; Narison, S.; Richard, J.M.; Blaizot, J.P.; Souillard, B.

1986-01-01

Phase transitions; lattice QCD; numerical simulation of lattice gauge theories; experimental research on gluonic mesons; QCD-duality sum rules; the bag model, potentials, and hadron spectra; and efficient Lagrangian functions and the Skyrme model are introduced [fr

Sum rules for nuclear collective excitations

International Nuclear Information System (INIS)

Bohigas, O.

1978-07-01

Characterizations of the response function and of integral properties of the strength function via a moment expansion are discussed. Sum rule expressions for the moments in the RPA are derived. The validity of these sum rules for both density independent and density dependent interactions is proved. For forces of the Skyrme type, analytic expressions for the plus one and plus three energy weighted sum rules are given for isoscalar monopole and quadrupole operators. From these, a close relationship between the monopole and quadrupole energies is shown and their dependence on incompressibility and effective mass is studied. The inverse energy weighted sum rule is computed numerically for the monopole operator, and an upper bound for the width of the monopole resonance is given. Finally the reliability of moments given by the RPA with effective interactions is discussed using simple soluble models for the hamiltonian, and also by comparison with experimental data

Transition form factors of π{sup 0},η and η{sup ′} mesons: What can be learned from anomaly sum rule?

Energy Technology Data Exchange (ETDEWEB)

Klopot, Yaroslav, E-mail: klopot@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Oganesian, Armen, E-mail: armen@itep.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation); Institute of Theoretical and Experimental Physics, 117218 Moscow (Russian Federation); Teryaev, Oleg, E-mail: teryaev@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, 141980 Dubna (Russian Federation)

2013-12-15

We studied the applications of the anomaly sum rule (ASR) to the transition form factors of light pseudoscalar mesons: π{sup 0},η and η{sup ′}. This nonperturbative QCD approach can be used even if the QCD factorization is broken. The status of possible small non-OPE corrections to continuum in comparison to BaBar and Belle data is explored. The accuracy of the applied method and the role of the quark mass contributions are discussed.

'Sum rules' for preequilibrium reactions

International Nuclear Information System (INIS)

Hussein, M.S.

1981-03-01

Evidence that suggests a correct relationship between the optical transmission matrix, P, and the several correlation widths, gamma sub(n), found in nsmission matrix, P, and the several correlation widths, n, found in multistep compound (preequilibrium) nuclear reactions, is presented. A second sum rule is also derived within the shell model approach to nuclear reactions. Indications of the potential usefulness of the sum rules in preequilibrium studies are given. (Author) [pt

Determination of {alpha}{sub s} from Gross-Llewellyn Smith sum rule by accounting for infrared renormalon

Energy Technology Data Exchange (ETDEWEB)

Contreras, C [Department of Physics, Universidad Tecn. Federico Santa Maria, Valparaiso (Chile); Cvetic, G [Department of Physics, Universidad Tecn. Federico Santa Maria, Valparaiso (Chile); Jeong, K S [Department of Physics, Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of); Lee, Taekoon [Department of Physics, Korea Advanced Institute of Science and Technology, Daejon (Korea, Republic of)

2003-08-01

We recapitulate the method which resums the truncated perturbation series of a physical observable in a way which takes into account the structure of the leading infrared renormalon. We apply the method to the Gross-Llewellyn Smith (GLS) sum rule. By confronting the obtained result with the experimentally extracted GLS value, we determine the value of the QCD coupling parameter, which turns out to agree with the present world average.

Transition sum rules in the shell model

Science.gov (United States)

Lu, Yi; Johnson, Calvin W.

2018-03-01

An important characterization of electromagnetic and weak transitions in atomic nuclei are sum rules. We focus on the non-energy-weighted sum rule (NEWSR), or total strength, and the energy-weighted sum rule (EWSR); the ratio of the EWSR to the NEWSR is the centroid or average energy of transition strengths from an nuclear initial state to all allowed final states. These sum rules can be expressed as expectation values of operators, which in the case of the EWSR is a double commutator. While most prior applications of the double commutator have been to special cases, we derive general formulas for matrix elements of both operators in a shell model framework (occupation space), given the input matrix elements for the nuclear Hamiltonian and for the transition operator. With these new formulas, we easily evaluate centroids of transition strength functions, with no need to calculate daughter states. We apply this simple tool to a number of nuclides and demonstrate the sum rules follow smooth secular behavior as a function of initial energy, as well as compare the electric dipole (E 1 ) sum rule against the famous Thomas-Reiche-Kuhn version. We also find surprising systematic behaviors for ground-state electric quadrupole (E 2 ) centroids in the s d shell.

The spin-dependent structure function of the proton g(1)(p) and a test of the Bjorken sum rule

Czech Academy of Sciences Publication Activity Database

Alekseev, M.; Alexakhin, V. Yu.; Alexandrov, Yu.; Alexeev, G. D.; Amoroso, A.; Austregisilio, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.; Chaberny, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Cotic, D.; Crespo, M.; Dalla Torre, S.; Das, S.; Dasgupta, S. S.; Denisov, O.; Dhara, L.; Diaz, V.; Donskov, S.; Doshita, N.; Duic, V.; Dünnweber, W.; Efremov, A.V.; El Alaoui, A.; Eversheim, P.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Friedrich, J.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.; Gazda, R.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmüller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Haas, F.; von Harrach, D.; Hasegawa, T.; Heinsius, F.; Hermann, R.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Höppner, Ch.; d'Hose, N.; Ilgner, C.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Jegou, G.; Joosten, R.; Kabuss, E.; Käfer, W.; Kang, D.; Ketzer, B.; Khaustov, G.; Khokhlov, Y.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.; Kolosov, V.; Kondo, K.; Königsmann, K.; Konopka, R.; Konorov, I.; Konstantinov, V.; Korzenev, A.; Kotzinian, A.; Kouznetsov, O.; Kowalik, K.; Krämer, M.; Kral, A.; Kroumchtein, Z.; Kuhn, R.; Kunne, F.; Kurek, K.; Lauser, L.; Le Goff, J.; Lednev, A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.; Mann, A.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Meyer, W.; Michigami, T.; Mikhailov, Y.; Moinester, M.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Nassalski, J.; Negrini, S.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.; Nunes, A.S.; Olshevsky, A.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pawlukiewicz-Kaminska, B.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.; Pontecorvo, G.; Pretz, J.; Quintans, C.; Rajotte, J.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ryabchikov, D.; Samoylenko, V.; Sandacz, A.; Santos, H.; Sapozhnikov, M.; Sarkar, S.; Savin, I.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schlütter, T.; Schmitt, L.; Schopferer, S.; Schröder, W.; Shevchenko, O.; Siebert, H.; Silva, L.; Sinha, L.; Sissakian, A.; Slunecka, M.; Smirnov, G.; Sosio, S.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Sulc, M.; Sulej, R.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.; Uhl, S.; Uman, I.; Virius, M.; Vlassov, N.; Vossen, A.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhao, J.; Zhuravlev, N.; Zvyagin, A.

2010-01-01

Roč. 690, č. 5 (2010), s. 466-472 ISSN 0370-2693 R&D Projects: GA MŠk ME 492 Institutional research plan: CEZ:AV0Z20650511 Keywords : deep inelastic scattering * structure function * QCD analysis * Bjorken sum rule Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 5.255, year: 2010

Fixed mass and scaling sum rules

International Nuclear Information System (INIS)

Ward, B.F.L.

1975-01-01

Using the correspondence principle (continuity in dynamics), the approach of Keppell-Jones-Ward-Taha to fixed mass and scaling current algebraic sum rules is extended so as to consider explicitly the contributions of all classes of intermediate states. A natural, generalized formulation of the truncation ideas of Cornwall, Corrigan, and Norton is introduced as a by-product of this extension. The formalism is illustrated in the familiar case of the spin independent Schwinger term sum rule. New sum rules are derived which relate the Regge residue functions of the respective structure functions to their fixed hadronic mass limits for q 2 → infinity. (Auth.)

Adler Function, DIS sum rules and Crewther Relations

International Nuclear Information System (INIS)

Baikov, P.A.; Chetyrkin, K.G.; Kuehn, J.H.

2010-01-01

The current status of the Adler function and two closely related Deep Inelastic Scattering (DIS) sum rules, namely, the Bjorken sum rule for polarized DIS and the Gross-Llewellyn Smith sum rule are briefly reviewed. A new result is presented: an analytical calculation of the coefficient function of the latter sum rule in a generic gauge theory in order O(α s 4 ). It is demonstrated that the corresponding Crewther relation allows to fix two of three colour structures in the O(α s 4 ) contribution to the singlet part of the Adler function.

The Q2-Dependence of the Gross-Llewellyn Smith Sum Rule and of the Parton Distributions

International Nuclear Information System (INIS)

Kataev, A.L.; AN SSSR, Moscow; Sidorov, A.V.

1994-01-01

We describe the results of our recent work on the determination of the value of the parameter Λ and of the Q 2 -dependence of the Gross-Llewellyn Smith (GLS) sum rule from the experimental data of the CCFR collaboration on neutrino-nucleon deep inelastic scattering, using the Jacobi polynomials QCD analysis. The new information on the Q 2 -dependence of the parton distributions is presented. 37 refs., 3 figs., 3 tabs

Isospin sum rules for inclusive cross-sections

NARCIS (Netherlands)

Rotelli, P.; Suttorp, L.G.

1972-01-01

A systematic analysis of isospin sum rules is presented for the distribution functions of strong, electromagnetic weak inclusive processes. The general expression for these sum rules is given and some new examples are presented.

Nonperturbative QCD and elastic processes at CEBAF energies

Energy Technology Data Exchange (ETDEWEB)

Radyushkin, A.V. [Old Dominion Univ., Norfolk, VA (United States)]|[Continuous Electron Beam Accelerator Facility, Newport News, VA (United States)

1994-04-01

The author outlines how one can approach nonperturbative aspects of the QCD dynamics studying elastic processes at energies accessible at upgraded CEBAF. The author`s point is that, in the absence of a complete theory of the nonperturbative effects, a possible way out is based on a systematic use of the QCD factorization procedure which separates theoretically understood ({open_quotes}known{close_quotes}) short-distance effects and nonperturbative ({open_quotes}unknown{close_quotes}) long-distance ones. The latter include hadronic distribution amplitudes, soft components of hadronic form factors etc. Incorporating the QCD sum rule version of the QCD factorization approach, one can relate these nonperturbative functions to more fundamental objects, vacuum condensates, which accumulate information about the nonperturbative structure of the QCD vacuum. The emerging QCD sum rule picture of hadronic form factors is characterized by a dominant role of essentially nonperturbative effects in the few GeV region, with perturbative mechanisms starting to show up for momentum transfers Q{sup 2} closer to 10 GeV{sup 2} and higher. Thus, increasing CEBAF energy provides a unique opportunity for a precision study of interplay between the perturbative and nonperturbative phenomena in the QCD description of elastic processes.

Nonperturbative QCD and elastic processes at CEBAF energies

International Nuclear Information System (INIS)

Radyushkin, A.V.

1994-01-01

The author outlines how one can approach nonperturbative aspects of the QCD dynamics studying elastic processes at energies accessible at upgraded CEBAF. The author's point is that, in the absence of a complete theory of the nonperturbative effects, a possible way out is based on a systematic use of the QCD factorization procedure which separates theoretically understood (open-quotes knownclose quotes) short-distance effects and nonperturbative (open-quotes unknownclose quotes) long-distance ones. The latter include hadronic distribution amplitudes, soft components of hadronic form factors etc. Incorporating the QCD sum rule version of the QCD factorization approach, one can relate these nonperturbative functions to more fundamental objects, vacuum condensates, which accumulate information about the nonperturbative structure of the QCD vacuum. The emerging QCD sum rule picture of hadronic form factors is characterized by a dominant role of essentially nonperturbative effects in the few GeV region, with perturbative mechanisms starting to show up for momentum transfers Q 2 closer to 10 GeV 2 and higher. Thus, increasing CEBAF energy provides a unique opportunity for a precision study of interplay between the perturbative and nonperturbative phenomena in the QCD description of elastic processes

Gluonium spectrum in QCD

International Nuclear Information System (INIS)

Dominguez, C.A.

1987-02-01

The scalar (0 ++ ) and the tensor (2 ++ ) gluonium spectrum is analyzed in the framework of QCD sum rules. Stable eigenvalue solutions, consistent with duality and low energy theorems, are obtained for the mass and width of these glueballs. (orig.)

Analyzing Bs - anti Bs mixing. Non-perturbative contributions to bag parameters from sum rules

International Nuclear Information System (INIS)

Mannel, T.; Pivovarov, A.A.; Russian Academy of Sciecnes, Moscow

2007-03-01

We use QCD sum rules to compute matrix elements of the ΔB=2 operators appearing in the heavy-quark expansion of the width difference of the B s mass eigenstates. Our analysis includes the leading-order operators Q and Q S , as well as the subleading operators R 2 and R 3 , which appear at next-to-leading order in the 1/m b expansion. We conclude that the violation of the factorization approximation for these matrix elements due to non-perturbative vacuum condensates is as low as 1-2%. (orig.)

Proof of Kochen–Specker Theorem: Conversion of Product Rule to Sum Rule

International Nuclear Information System (INIS)

Toh, S.P.; Zainuddin, Hishamuddin

2009-01-01

Valuation functions of observables in quantum mechanics are often expected to obey two constraints called the sum rule and product rule. However, the Kochen–Specker (KS) theorem shows that for a Hilbert space of quantum mechanics of dimension d ≤ 3, these constraints contradict individually with the assumption of value definiteness. The two rules are not irrelated and Peres [Found. Phys. 26 (1996) 807] has conceived a method of converting the product rule into a sum rule for the case of two qubits. Here we apply this method to a proof provided by Mermin based on the product rule for a three-qubit system involving nine operators. We provide the conversion of this proof to one based on sum rule involving ten operators. (general)

Gaussian sum rules for optical functions

International Nuclear Information System (INIS)

Kimel, I.

1981-12-01

A new (Gaussian) type of sum rules (GSR) for several optical functions, is presented. The functions considered are: dielectric permeability, refractive index, energy loss function, rotatory power and ellipticity (circular dichroism). While reducing to the usual type of sum rules in a certain limit, the GSR contain in general, a Gaussian factor that serves to improve convergence. GSR might be useful in analysing experimental data. (Author) [pt

Adler Function, Bjorken Sum Rule, and the Crewther Relation to Order αs4 in a General Gauge Theory

International Nuclear Information System (INIS)

Baikov, P. A.; Chetyrkin, K. G.; Kuehn, J. H.

2010-01-01

We compute, for the first time, the order α s 4 contributions to the Bjorken sum rule for polarized electron-nucleon scattering and to the (nonsinglet) Adler function for the case of a generic color gauge group. We confirm at the same order a (generalized) Crewther relation which provides a strong test of the correctness of our previously obtained results: the QCD Adler function and the five-loop β function in quenched QED. In particular, the appearance of an irrational contribution proportional to ζ 3 in the latter quantity is confirmed. We obtain the commensurate scale equation relating the effective strong coupling constants as inferred from the Bjorken sum rule and from the Adler function at order α s 4 .

Singular f-sum rule for superfluid 4He

International Nuclear Information System (INIS)

Wong, V.K.

1979-01-01

The validity and applicability to inelastic neutron scattering of a singular f-sum rule for superfluid helium, proposed by Griffin to explain the rhosub(s) dependence in S(k, ω) as observed by Woods and Svensson, are examined in the light of similar sum rules rigorously derived for anharmonic crystals and Bose liquids. It is concluded that the singular f-sum rules are only of microscopic interest. (Auth,)

Superconvergent sum rules for the normal reflectivity

International Nuclear Information System (INIS)

Furuya, K.; Zimerman, A.H.; Villani, A.

1976-05-01

Families of superconvergent relations for the normal reflectivity function are written. Sum rules connecting the difference of phases of the reflectivities of two materials are also considered. Finally superconvergence relations and sum rules for magneto-reflectivity in the Faraday and Voigt regimes are also studied

Spectral sum rules for the three-body problem

International Nuclear Information System (INIS)

Bolle, D.; Osborn, T.A.

1982-01-01

This paper derives a number of sum rules for nonrelativistic three-body scattering. These rules are valid for any finite region μ in the six-dimensional coordinate space. They relate energy moments of the trace of the onshell time-delay operator to the energy-weighted probability for finding the three-body bound-state wave functions in the region μ. If μ is all of the six-dimensional space, the global form of the sum rules is obtained. In this form the rules constitute higher-order Levinson's theorems for the three-body problem. Finally, the sum rules are extended to allow the energy momtns have complex powers

Sum rules for neutrino oscillations

International Nuclear Information System (INIS)

Kobzarev, I.Yu.; Martemyanov, B.V.; Okun, L.B.; Schepkin, M.G.

1981-01-01

Sum rules for neutrino oscillations are obtained. The derivation of the general form of the s matrix for two stage process lsub(i)sup(-)→ν→lsub(k)sup(+-) (where lsub(i)sup(-)e, μ, tau, ... are initial leptons with flavor i and lsub(k)sup(+-) is final lepton) is presented. The consideration of two stage process lsub(i)sup(-)→ν→lsub(k)sup(+-) gives the possibility to take into account neutrino masses and to obtain the expressions for the oscillating cross sections. In the case of Dirac and left-handed Majorana neutrino is obtained the sum rule for the quantities 1/Vsub(K)σ(lsub(i)sup(-)→lsub(K)sup(+-)), (where Vsub(K) is a velocity of lsub(K)). In the left-handed Majorana neutrino case there is an additional antineutrino admixture leading to lsub(i)sup(-)→lsub(K)sup(+) process. Both components (neutrino and antineutrino) oscillate independently. The sums Σsub(K)1/Vsub(k)σ(lsub(i)sup(-) - lsub(K)sup(+-) then oscillate due to the presence of left-handed antineutrinos and right-handed neutrinos which do not take part in weak interactions. If right-handed currents are added sum rules analogous to considered above may be obtained. All conclusions are valid in the general case when CP is not conserved [ru

Systematics of strength function sum rules

Directory of Open Access Journals (Sweden)

Calvin W. Johnson

2015-11-01

Full Text Available Sum rules provide useful insights into transition strength functions and are often expressed as expectation values of an operator. In this letter I demonstrate that non-energy-weighted transition sum rules have strong secular dependences on the energy of the initial state. Such non-trivial systematics have consequences: the simplification suggested by the generalized Brink–Axel hypothesis, for example, does not hold for most cases, though it weakly holds in at least some cases for electric dipole transitions. Furthermore, I show the systematics can be understood through spectral distribution theory, calculated via traces of operators and of products of operators. Seen through this lens, violation of the generalized Brink–Axel hypothesis is unsurprising: one expects sum rules to evolve with excitation energy. Furthermore, to lowest order the slope of the secular evolution can be traced to a component of the Hamiltonian being positive (repulsive or negative (attractive.

Light relativistic bound states in high temperature QCD

International Nuclear Information System (INIS)

Zahed, Ismail

1991-01-01

The nonperturbative structure of high temperature QCD is combined with generalized sum-rules arguments to analyse gauge invariant correlation functions in real time. It is shown that for a plausible choice of condensates, QCD at high temperature exhibits color singlet excitations as opposed to merely screened quarks and gluons. (author). 14 refs.; 2 figs

B-decay form factors from QCD sum rules

International Nuclear Information System (INIS)

Offen, Nils

2008-01-01

In the Standard Model of particle physics there is only one source of CP-violation. Namely, a single complex phase in the unitary 3 x 3 CKM-Matrix governing flavor transitions in the weak interaction. The unitarity is usually visualized by a triangle in the complex ρ - η-plane. Therefore testing this framework comes down to measuring weak decays, relating observables to sides and angles of this so called Unitarity Triangle(UT). Particular interest in this respect is payed to decays of mesons containing a heavy b-quark, giving the opportunity to alone determine all parameters of the UT. Doing this is far from easy. Besides tedious experimental measurements the theoretical calculations are plagued by hadronic quantities which cannot be determined by perturbation theory. In this work several of these quantities so called form factors are computed using the well known method of light cone sum rules(LCSR). Two different setups have been used. One, established in this work, utilizing a correlation function with an on-shell B-Meson and one following the traditional calculation by taking the light meson on-shell. Both using light cone expansion in the respective on-shell mesons distribution amplitudes. While the first approach allows to calculate a whole bunch of phenomenologically interesting quantities by just changing Dirac-structures of the relevant currents it has the drawback that it does not have access to the well developed twist expansion of the latter. To incorporate higher Fock-state contributions the first models for three-particle distribution amplitudes of the B-Meson have been derived. α s -corrections remain out of the scope of this work. Nevertheless does a comparison with more sophisticated methods show an encouraging numerical agreement. In the second setup all known corrections especially the never verified α s -corrections to Twist three terms have been recalculated and a competitive result for the CKM-matrixelement vertical stroke V ub vertical

Sum rules and spectral density flow in QCD and in superconformal theories

Directory of Open Access Journals (Sweden)

Costantini Antonio

2014-01-01

Full Text Available We discuss the signature of the anomalous breaking of the superconformal symmetry in N${\\cal N}$ = 1 super Yang Mills theory and its manifestation in the form of anomaly poles. Moreover, we describe the massive deformations of the N${\\cal N}$ = 1 theory and the spectral densities of the corresponding anomaly form factors. These are characterized by spectral densities which flow with the mass deformation and turn the continuum contributions from the two-particle cuts of the intermediate states into poles, with a single sum rule satisfied by each component. The poles can be interpreted as signaling the exchange of a composite axion/dilaton/dilatino (ADD multiplet in the effective Lagrangian. We conclude that global anomalous currents characterized by a single flow in the perturbative picture always predict the existence of composite interpolating fields.

Cosmic-ray sum rules

International Nuclear Information System (INIS)

Frandsen, Mads T.; Masina, Isabella; Sannino, Francesco

2011-01-01

We introduce new sum rules allowing to determine universal properties of the unknown component of the cosmic rays; we show how they can be used to predict the positron fraction at energies not yet explored by current experiments, and to constrain specific models.

Compton scattering from nuclei and photo-absorption sum rules

International Nuclear Information System (INIS)

Gorchtein, Mikhail; Hobbs, Timothy; Londergan, J. Timothy; Szczepaniak, Adam P.

2011-01-01

We revisit the photo-absorption sum rule for real Compton scattering from the proton and from nuclear targets. In analogy with the Thomas-Reiche-Kuhn sum rule appropriate at low energies, we propose a new 'constituent quark model' sum rule that relates the integrated strength of hadronic resonances to the scattering amplitude on constituent quarks. We study the constituent quark model sum rule for several nuclear targets. In addition, we extract the α=0 pole contribution for both proton and nuclei. Using the modern high-energy proton data, we find that the α=0 pole contribution differs significantly from the Thomson term, in contrast with the original findings by Damashek and Gilman.

Adler-Weisberger sum rule for WLWL→WLWL scattering

International Nuclear Information System (INIS)

Pham, T.N.

1991-01-01

We analyse the Adler-Weisberger sum rule for W L W L →W L W L scattering. We find that at some energy, the W L W L total cross section must be large to saturate the sum rule. Measurements at future colliders would be needed to check the sum rule and to obtain the decay rates Γ(H→W L W L , Z L Z L ) which would be modified by the existence of a P-wave vector meson resonance in the standard model with strongly interacting Higgs sector or in technicolour models. (orig.)

Sum rules for the quarkonium systems

International Nuclear Information System (INIS)

Burnel, A.; Caprasse, H.

1980-01-01

In the framework of the radial Schroedinger equation we derive in a very simple way sum rules relating the potential to physical quantities such as the energy eigenvalues and the square of the lth derivative of the eigenfunctions at the origin. These sum rules contain as particular cases well-known results such as the quantum version of the Clausius theorem in classical mechanics as well as Kramers's relations for the Coulomb potential. Several illustrations are given and the possibilities of applying them to the quarkonium systems are considered

Coulomb sum rules in the relativistic Fermi gas model

International Nuclear Information System (INIS)

Do Dang, G.; L'Huillier, M.; Nguyen Giai, Van.

1986-11-01

Coulomb sum rules are studied in the framework of the Fermi gas model. A distinction is made between mathematical and observable sum rules. Differences between non-relativistic and relativistic Fermi gas predictions are stressed. A method to deduce a Coulomb response function from the longitudinal response is proposed and tested numerically. This method is applied to the 40 Ca data to obtain the experimental Coulomb sum rule as a function of momentum transfer

Sum rules for nuclear excitations with the Skyrme-Landau interaction

International Nuclear Information System (INIS)

Liu Kehfei; Luo Hongde; Ma Zhongyu; Feng Man; Shen Qingbiao

1991-01-01

The energy-weighted sum rules for electric, magnetic, Fermi and Gamow-Teller transitions with the Skyrme-Landau interaction are derived from the double commutators and numerically calculated in a HF + RPA formalism. As a numerical check of the Thouless theorem, our self-consistent calculations show that the calculated RPA strengths exhaust more than 85% of the sum rules in most cases. The well known non-energy-weighted sum rules for Fermi and Gamow-Teller transitions are also checked numerically. The sum rules are exhausted by more than 94% in these cases. (orig.)

Measurement of αs(Q2) from the Gross endash Llewellyn Smith Sum Rule

International Nuclear Information System (INIS)

Johnson, R.A.; Vakili, M.; Kim, J.H.; Arroyo, C.G.; Bazarko, A.O.; Conrad, J.; King, B.J.; Lefmann, W.C.; McNulty, C.; Mishra, S.R.; Quintas, P.Z.; Romosan, A.; Schellman, H.; Sciulli, F.J.; Seligman, W.G.; Shaevitz, M.H.; Spentzouris, P.; Stern, E.G.; Bernstein, R.H.; Lamm, M.J.; Marsh, W.; McFarland, K.S.; Yu, J.; Bolton, T.; Naples, D.; Barbaro, L. de; Harris, D.A.; Barbaro, P. de; Bodek, A.; Budd, H.; Sakumoto, W.K.; Yang, U.K.; Kinnel, T.; Smith, W.H.

1998-01-01

We extract a set of values for the Gross endash Llewellyn Smith sum rule at different values of 4-momentum transfer squared (Q 2 ), by combining revised CCFR neutrino data with data from other neutrino deep-inelastic scattering experiments for 1 2 2 /c 2 . A comparison with the order α 3 s theoretical predictions yields a determination of α s at the scale of the Z -boson mass of 0.114± 0.009 0.012 . This measurement provides a new and useful test of perturbative QCD at low Q 2 , because of the low uncertainties in the higher order calculations. copyright 1998 The American Physical Society

Heavy-to-light form factors: Sum rules on the light cone and beyond

International Nuclear Information System (INIS)

Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano

2007-01-01

We report the first systematic analysis of the off-light-cone effects in sum rules for heavy-to-light form factors. These effects are investigated in a model based on scalar constituents, which allows a technically rather simple analysis but has the essential features of the analogous QCD calculation. The correlator relevant for the extraction of the heavy-to-light form factor is calculated in two different ways: first, by adopting the full Bethe-Salpeter amplitude of the light meson and, second, by performing the expansion of this amplitude near the light cone x 2 =0. We demonstrate that the contributions to the correlator from the light-cone term x 2 =0 and the off-light-cone terms x 2 ≠0 have the same order in the 1/m Q expansion. The light-cone correlator, corresponding to x 2 =0, is shown to systematically overestimate the full correlator, the difference being ∼Λ QCD /δ, with δ the continuum subtraction parameter of order 1 GeV. Numerically, this difference is found to be 10 divide 20%

Light cone sum rules in nonabelian gauge field theory

Energy Technology Data Exchange (ETDEWEB)

Mallik, S [Bern Univ. (Switzerland). Inst. fuer Theoretische Physik

1981-03-24

The author examines, in the context of nonabelian gauge field theory, the derivation of the light cone sum rules which were obtained earlier on the assumption of dominance of canonical singularity in the current commutator on the light cone. The retarded scaling functions appearing in the sum rules are numbers known in terms of the charges of the quarks and the number of quarks and gluons in the theory. Possible applications of the sum rules are suggested.

Light cone sum rules for single-pion electroproduction

International Nuclear Information System (INIS)

Mallik, S.

1978-01-01

Light cone dispersion sum rules (of low energy and superconvergence types) are derived for nucleon matrix elements of the commutator involving electromagnetic and divergence of axial vector currents. The superconvergence type sum rules in the fixed mass limit are rewritten without requiring the knowledge of Regge subtractions. The retarded scaling functions occurring in these sum rules are evaluated within the framework of quark light cone algebra of currents. Besides a general consistency check of the framework underlying the derivation, the author infers, on the basis of crude evaluation of scaling functions, an upper limit of 100 MeV for the bare mass of nonstrange quarks. (Auth.)

Moessbauer sum rules for use with synchrotron sources

International Nuclear Information System (INIS)

Lipkin, Harry J.

1999-01-01

The availability of tunable synchrotron radiation sources with millivolt resolution has opened new prospects for exploring dynamics of complex systems with Moessbauer spectroscopy. Early Moessbauer treatments and moment sum rules are extended to treat inelastic excitations measured in synchrotron experiments, with emphasis on the unique new conditions absent in neutron scattering and arising in resonance scattering: prompt absorption, delayed emission, recoil-free transitions and coherent forward scattering. The first moment sum rule normalizes the inelastic spectrum. New sum rules obtained for higher moments include the third moment proportional to the second derivative of the potential acting on the Moessbauer nucleus and independent of temperature in the the harmonic approximation

Sum Rules, Classical and Quantum - A Pedagogical Approach

Science.gov (United States)

Karstens, William; Smith, David Y.

2014-03-01

Sum rules in the form of integrals over the response of a system to an external probe provide general analytical tools for both experiment and theory. For example, the celebrated f-sum rule gives a system's plasma frequency as an integral over the optical-dipole absorption spectrum regardless of the specific spectral distribution. Moreover, this rule underlies Smakula's equation for the number density of absorbers in a sample in terms of the area under their absorption bands. Commonly such rules are derived from quantum-mechanical commutation relations, but many are fundamentally classical (independent of ℏ) and so can be derived from more transparent mechanical models. We have exploited this to illustrate the fundamental role of inertia in the case of optical sum rules. Similar considerations apply to sum rules in many other branches of physics. Thus, the ``attenuation integral theorems'' of ac circuit theory reflect the ``inertial'' effect of Lenz's Law in inductors or the potential energy ``storage'' in capacitors. These considerations are closely related to the fact that the real and imaginary parts of a response function cannot be specified independently, a result that is encapsulated in the Kramers-Kronig relations. Supported in part by the US Department of Energy, Office of Nuclear Physics under contract DE-AC02-06CH11357.

Derivation of sum rules for quark and baryon fields

International Nuclear Information System (INIS)

Bongardt, K.

1978-01-01

In an analogous way to the Weinberg sum rules, two spectral-function sum rules for quark and baryon fields are derived by means of the concept of lightlike charges. The baryon sum rules are valid for the case of SU 3 as well as for SU 4 and the one-particle approximation yields a linear mass relation. This relation is not in disagreement with the normal linear GMO formula for the baryons. The calculated masses of the first resonance states agree very well with the experimental data

On the Laplace transform of the Weinberg type sum rules

International Nuclear Information System (INIS)

Narison, S.

1981-09-01

We consider the Laplace transform of various sum rules of the Weinberg type including the leading non-perturbative effects. We show from the third type Weinberg sum rules that 7.5 to 8.9 1 coupling to the W boson, while the second sum rule gives an upper bound on the A 1 mass (Msub(A 1 ) < or approx. 1.25 GeV). (author)

Death to perturbative QCD in exclusive processes?

Energy Technology Data Exchange (ETDEWEB)

Eckardt, R.; Hansper, J.; Gari, M.F. [Institut fuer Theoretische Physik, Bochum (Germany)

1994-04-01

The authors discuss the question of whether perturbative QCD is applicable in calculations of exclusive processes at available momentum transfers. They show that the currently used method of determining hadronic quark distribution amplitudes from QCD sum rules yields wave functions which are completely undetermined because the polynomial expansion diverges. Because of the indeterminacy of the wave functions no statement can be made at present as to whether perturbative QCD is valid. The authors emphasize the necessity of a rigorous discussion of the subject and the importance of experimental data in the range of interest.

Quark virtuality and QCD vacuum condensates

International Nuclear Information System (INIS)

Zhou Lijuan; Ma Weixing

2004-01-01

Based on the Dyson-Schwinger equations (DSEs) in the 'rainbow' approximation, the authors investigate the quark virtuality in the vacuum state and quantum-chromodynamics (QCD) vacuum condensates. In particular, authors calculate the local quark vacuum condensate and quark-gluon mixed condensates, and then the virtuality of quark. The calculated quark virtualities are λ u,d 2 =0.7 GeV 2 for u, d quarks, and λ s 2 =1.6 GeV 2 for s quark. The theoretical predictions are consistent with empirical values used in QCD sum rules, and also fit to lattice QCD predictions

The AdS/CFT Correspondence and Holographic QCD

International Nuclear Information System (INIS)

Erlich, J.

2012-01-01

Holographic QCD is an extra-dimensional approach to modeling QCD resonances and their interactions. Holographic models encode information about chiral symmetry breaking, Weinberg sum rules, vector meson dominance, and other phenomenological features of QCD. There are two complementary approaches to holographic model building: a top-down approach which begins with string-theory brane configurations, and a bottom-up approach which is more phenomenological. In this talk I will describe the AdS/CFT correspondence, which motivates Holographic QCD, and the techniques used to build holographic models of QCD and to calculate observables in those models. I will also discuss an intriguing light cone approach to Holographic QCD discovered by Brodsky and De Teramond. (author)

Integrals of Lagrange functions and sum rules

Energy Technology Data Exchange (ETDEWEB)

Baye, Daniel, E-mail: dbaye@ulb.ac.be [Physique Quantique, CP 165/82, Universite Libre de Bruxelles, B 1050 Bruxelles (Belgium); Physique Nucleaire Theorique et Physique Mathematique, CP 229, Universite Libre de Bruxelles, B 1050 Bruxelles (Belgium)

2011-09-30

Exact values are derived for some matrix elements of Lagrange functions, i.e. orthonormal cardinal functions, constructed from orthogonal polynomials. They are obtained with exact Gauss quadratures supplemented by corrections. In the particular case of Lagrange-Laguerre and shifted Lagrange-Jacobi functions, sum rules provide exact values for matrix elements of 1/x and 1/x{sup 2} as well as for the kinetic energy. From these expressions, new sum rules involving Laguerre and shifted Jacobi zeros and weights are derived. (paper)

Inclusive sum rules and spectra of neutrons at the ISR

International Nuclear Information System (INIS)

Grigoryan, A.A.

1975-01-01

Neutron spectra in pp collisions at ISR energies are studied in the framework of sum rules for inclusive processes. The contributions of protons, π- and E- mesons to the energy sum rule are calculated at √5 = 53 GeV. It is shown by means of this sum rule that the spectra of neutrons at the ISR are in contradiction with the spectra of other particles also measured at the ISR

Luttinger and Hubbard sum rules: are they compatible?

International Nuclear Information System (INIS)

Matho, K.

1992-01-01

A so-called Hubbard sum rule determines the weight of a satellite in fermionic single-particle excitations with strong local repulsion (U→∞). Together with the Luttinger sum rule, this imposes two different energy scales on the remaining finite excitations. In the Hubbard chain, this has been identified microscopically as being due to a separation of spin and charge. (orig.)

Energy-weighted sum rules for mesons in hot and dense matter

NARCIS (Netherlands)

Cabrera, D.; Polls, A.; Ramos, A.; Tolos Rigueiro, Laura

2009-01-01

We study energy-weighted sum rules of the pion and kaon propagator in nuclear matter at finite temperature. The sum rules are obtained from matching the Dyson form of the meson propagator with its spectral Lehmann representation at low and high energies. We calculate the sum rules for specific

β-decay in the Skyrme-Witten representation of QCD

International Nuclear Information System (INIS)

Snyderman, N.J.

1991-01-01

The renormalized coupling strength of the β-decay axial vector current is related to π ± p cross sections through the Adler-Weisberger sum rule, that follows from chiral symmetry. We attempt to understand the Adler-Weisberger sum rule in the 1/N c expansion in QCD, and in Skyrme-Witten model that realizes the 1/N c expansion in the low energy limit, using it to explicitly calculate both g A and the π ± p cross sections

Complex-energy approach to sum rules within nuclear density functional theory

Science.gov (United States)

Hinohara, Nobuo; Kortelainen, Markus; Nazarewicz, Witold; Olsen, Erik

2015-04-01

Background: The linear response of the nucleus to an external field contains unique information about the effective interaction, the correlations governing the behavior of the many-body system, and the properties of its excited states. To characterize the response, it is useful to use its energy-weighted moments, or sum rules. By comparing computed sum rules with experimental values, the information content of the response can be utilized in the optimization process of the nuclear Hamiltonian or the nuclear energy density functional (EDF). But the additional information comes at a price: compared to the ground state, computation of excited states is more demanding. Purpose: To establish an efficient framework to compute energy-weighted sum rules of the response that is adaptable to the optimization of the nuclear EDF and large-scale surveys of collective strength, we have developed a new technique within the complex-energy finite-amplitude method (FAM) based on the quasiparticle random-phase approximation (QRPA). Methods: To compute sum rules, we carry out contour integration of the response function in the complex-energy plane. We benchmark our results against the conventional matrix formulation of the QRPA theory, the Thouless theorem for the energy-weighted sum rule, and the dielectric theorem for the inverse-energy-weighted sum rule. Results: We derive the sum-rule expressions from the contour integration of the complex-energy FAM. We demonstrate that calculated sum-rule values agree with those obtained from the matrix formulation of the QRPA. We also discuss the applicability of both the Thouless theorem about the energy-weighted sum rule and the dielectric theorem for the inverse-energy-weighted sum rule to nuclear density functional theory in cases when the EDF is not based on a Hamiltonian. Conclusions: The proposed sum-rule technique based on the complex-energy FAM is a tool of choice when optimizing effective interactions or energy functionals. The method

Light-cone sum rules: A SCET-based formulation

CERN Document Server

De Fazio, F; Hurth, Tobias; Feldmann, Th.

2007-01-01

We describe the construction of light-cone sum rules (LCSRs) for exclusive $B$-meson decays into light energetic hadrons from correlation functions within soft-collinear effective theory (SCET). As an example, we consider the SCET sum rule for the $B \\to \\pi$ transition form factor at large recoil, including radiative corrections from hard-collinear loop diagrams at first order in the strong coupling constant.

3He electron scattering sum rules

International Nuclear Information System (INIS)

Kim, Y.E.; Tornow, V.

1982-01-01

Electron scattering sum rules for 3 He are derived with a realistic ground-state wave function. The theoretical results are compared with the experimentally measured integrated cross sections. (author)

Counter-ions at single charged wall: Sum rules.

Science.gov (United States)

Samaj, Ladislav

2013-09-01

For inhomogeneous classical Coulomb fluids in thermal equilibrium, like the jellium or the two-component Coulomb gas, there exists a variety of exact sum rules which relate the particle one-body and two-body densities. The necessary condition for these sum rules is that the Coulomb fluid possesses good screening properties, i.e. the particle correlation functions or the averaged charge inhomogeneity, say close to a wall, exhibit a short-range (usually exponential) decay. In this work, we study equilibrium statistical mechanics of an electric double layer with counter-ions only, i.e. a globally neutral system of equally charged point-like particles in the vicinity of a plain hard wall carrying a fixed uniform surface charge density of opposite sign. At large distances from the wall, the one-body and two-body counter-ion densities go to zero slowly according to the inverse-power law. In spite of the absence of screening, all known sum rules are shown to hold for two exactly solvable cases of the present system: in the weak-coupling Poisson-Boltzmann limit (in any spatial dimension larger than one) and at a special free-fermion coupling constant in two dimensions. This fact indicates an extended validity of the sum rules and provides a consistency check for reasonable theoretical approaches.

Moessbauer sum rules for use with synchrotron sources

International Nuclear Information System (INIS)

Lipkin, H.J.

1995-01-01

The availability of tunable synchrotron radiation sources with millivolt resolution has opened prospects for exploring dynamics of complex systems with Moessbauer spectroscopy. Early Moessbauer treatments and moment sum rules are extended to treat inelastic excitations measured in synchrotron experiments, with emphasis on the unique conditions absent in neutron scattering and arising in resonance scattering: prompt absorption, delayed emission, recoilfree transitions, and coherent forward scattering. The first moment sum rule normalizes the inelastic spectrum. Sum rules obtained for higher moments include the third moment proportional to the second derivative of the potential acting on the Moessbauer nucleus and independent of temperature in the harmonic approximation. Interesting information may be obtained on the behavior of the potential acting on this nucleus in samples not easily investigated with neutron scattering, e.g., small samples, thin films, time-dependent structures, and amorphous-metallic high pressure phases

GDH sum rule measurement at low Q2

International Nuclear Information System (INIS)

Bianchi, N.

1996-01-01

The Gerasimov-Drell-Hearn (GDH) sum rule is based on a general dispersive relation for the forward Compton scattering. Multipole analysis suggested the possible violation of the sum rule. Some propositions have been made to modify the original GDH expression. An effort is now being made in several laboratories to shred some light on this topic. The purposes of the different planned experiments are briefly presented according to their Q 2 range

Coherent-state representation for the QCD ground state

International Nuclear Information System (INIS)

Celenza, L.S.; Ji, C.; Shakin, C.M.

1987-01-01

We make use of the temporal gauge to construct a coherent state which is meant to describe the gluon condensate in the QCD vacuum under the assumption that the condensate is in a zero-momentum mode. The state so constructed is a color singlet and will yield finite, nonperturbative vacuum expectation values such as . (This matrix element is found to have a value of about 0.012 GeV 4 in QCD sum-rule studies.)

Symbolic methods for the evaluation of sum rules of Bessel functions

International Nuclear Information System (INIS)

Babusci, D.; Dattoli, G.; Górska, K.; Penson, K. A.

2013-01-01

The use of the umbral formalism allows a significant simplification of the derivation of sum rules involving products of special functions and polynomials. We rederive in this way known sum rules and addition theorems for Bessel functions. Furthermore, we obtain a set of new closed form sum rules involving various special polynomials and Bessel functions. The examples we consider are relevant for applications ranging from plasma physics to quantum optics

B --> K$*\\gamma$ from hybrid sum rule

CERN Document Server

Narison, Stéphan

1994-01-01

Using the {\\it hybrid} moments-Laplace sum rule (HSR), which is well-defined for M_b \\rar \\infty, in contrast with the popular double Borel (Laplace) sum rule (DLSR), which blows up in this limit when applied to the heavy-to-light processes, we show that the form factor of the B \\rar K^* \\ \\gamma radiative transition is dominated by the light-quark condensate for M_b \\rar \\infty and behaves like \\sqrt M_b. The form factor is found to be F^{B\\rar K^*}_1(0) \\simeq (30.8 \\pm 1.3 \\pm 3.6 \\pm 0.6)\\times 10^{-2}, where the errors come respectively from the procedure in the sum rule analysis, the errors in the input and in the SU(3)_f-breaking parameters. This result leads to Br(B\\rar K^* \\ \\gamma) \\simeq (4.45 \\pm 1.12) \\times 10^{-5} in agreement with the recent CLEO data. Parametrization of the M_b-dependence of the form factor including the SU(3)_f-breaking effects is given in (26), which leads to F^{B\\rar K^*}_1(0)/ F^{B\\rar \\rho}_1(0) \\simeq (1.14 \\pm 0.02).

Neutrino mass sum rules and symmetries of the mass matrix

Energy Technology Data Exchange (ETDEWEB)

Gehrlein, Julia [Karlsruhe Institute of Technology, Institut fuer Theoretische Teilchenphysik, Karlsruhe (Germany); Universidad Autonoma de Madrid, Departamento de Fisica Teorica, Madrid (Spain); Instituto de Fisica Teorica UAM/CSIC, Madrid (Spain); Spinrath, Martin [Karlsruhe Institute of Technology, Institut fuer Theoretische Teilchenphysik, Karlsruhe (Germany); National Center for Theoretical Sciences, Physics Division, Hsinchu (China)

2017-05-15

Neutrino mass sum rules have recently gained again more attention as a powerful tool to discriminate and test various flavour models in the near future. A related question which has not yet been discussed fully satisfactorily was the origin of these sum rules and if they are related to any residual or accidental symmetry. We will address this open issue here systematically and find previous statements confirmed. Namely, the sum rules are not related to any enhanced symmetry of the Lagrangian after family symmetry breaking but they are simply the result of a reduction of free parameters due to skillful model building. (orig.)

Analyzing B{sub s} - anti B{sub s} mixing. Non-perturbative contributions to bag parameters from sum rules

Energy Technology Data Exchange (ETDEWEB)

Mannel, T. [Siegen Univ. (Germany). FB 7, Theoretische Physik; Pecjak, B.D. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Pivovarov, A.A. [Siegen Univ. (Germany). FB 7, Theoretische Physik]|[Russian Academy of Sciecnes, Moscow (Russian Federation). Inst. for Nuclear Research

2007-03-15

We use QCD sum rules to compute matrix elements of the {delta}B=2 operators appearing in the heavy-quark expansion of the width difference of the B{sub s} mass eigenstates. Our analysis includes the leading-order operators Q and Q{sub S}, as well as the subleading operators R{sub 2} and R{sub 3}, which appear at next-to-leading order in the 1/m{sub b} expansion. We conclude that the violation of the factorization approximation for these matrix elements due to non-perturbative vacuum condensates is as low as 1-2%. (orig.)

Sum rules for quasifree scattering of hadrons

Science.gov (United States)

Peterson, R. J.

2018-02-01

The areas d σ /d Ω of fitted quasifree scattering peaks from bound nucleons for continuum hadron-nucleus spectra measuring d2σ /d Ω d ω are converted to sum rules akin to the Coulomb sums familiar from continuum electron scattering spectra from nuclear charge. Hadronic spectra with or without charge exchange of the beam are considered. These sums are compared to the simple expectations of a nonrelativistic Fermi gas, including a Pauli blocking factor. For scattering without charge exchange, the hadronic sums are below this expectation, as also observed with Coulomb sums. For charge exchange spectra, the sums are near or above the simple expectation, with larger uncertainties. The strong role of hadron-nucleon in-medium total cross sections is noted from use of the Glauber model.

Nucleon form factors and hidden symmetry in holographic QCD

International Nuclear Information System (INIS)

Hong, D.K.; Rho, M.; Yee, H.-U.; Yi, P.

2007-10-01

The vector dominance of the electromagnetic (EM) form factors both for mesons and baryons arises naturally in holographic QCD, where both the number of colors and the 't Hooft coupling are taken to be very large, offering a bona-fide derivation of the notion of vector dominance. The crucial ingredient for this is the infinite tower of vector mesons in the approximations made which share features that are characteristic of the quenched approximation in lattice QCD. We approximate the infinite sum by contributions from the lowest four vector mesons of the tower which turn out to saturate the charge and magnetic moment sum rules within a few % and compute them totally free of unknown parameters for momentum transfers Q 2 approx.= 1 GeV 2 . We identify certain observables that can be reliably computed within the approximations and others that are not, and discuss how the improvement of the latter can enable one to bring holographic QCD closer to QCD proper. (author)

Spectral sum rule for time delay in R2

International Nuclear Information System (INIS)

Osborn, T.A.; Sinha, K.B.; Bolle, D.; Danneels, C.

1985-01-01

A local spectral sum rule for nonrelativistic scattering in two dimensions is derived for the potential class velement ofL 4 /sup // 3 (R 2 ). The sum rule relates the integral over all scattering energies of the trace of the time-delay operator for a finite region Σis contained inR 2 to the contributions in Σ of the pure point and singularly continuous spectra

Forward Compton scattering with weak neutral current: Constraints from sum rules

Directory of Open Access Journals (Sweden)

Mikhail Gorchtein

2015-07-01

Full Text Available We generalize forward real Compton amplitude to the case of the interference of the electromagnetic and weak neutral current, formulate a low-energy theorem, relate the new amplitudes to the interference structure functions and obtain a new set of sum rules. We address a possible new sum rule that relates the product of the axial charge and magnetic moment of the nucleon to the 0th moment of the structure function g5(ν,0. For the dispersive γZ-box correction to the proton's weak charge, the application of the GDH sum rule allows us to reduce the uncertainty due to resonance contributions by a factor of two. The finite energy sum rule helps addressing the uncertainty in that calculation due to possible duality violations.

Polarizability sum rules in QED

International Nuclear Information System (INIS)

Llanta, E.; Tarrach, R.

1978-01-01

The well founded total photoproduction and the, assumed subtraction free, longitudinal photoproduction polarizability sum rules are checked in QED at the lowest non-trivial order. The first one is shown to hold, whereas the second one turns out to need a subtraction, which makes its usefulness for determining the electromagnetic polarizabilities of the nucleons quite doubtful. (Auth.)

Quark-spin isospin sum rules and the Adler-Weisberger relation in nuclei

International Nuclear Information System (INIS)

Delorme, J.; Ericson, M.

1982-01-01

We use a quark model to extend the classical Gamow-Teller sum rule for the difference of the β - and β + strengths to excitations of the nucleon (mainly the Δ isobar). A schematic model illustrates the realization of the new sum rule when a particle-hole force is introduced. We discuss the connection of our result with the model-independent Adler-Weisberger sum rule. (orig.)

Exclusive hadronic and nuclear processes in QCD

International Nuclear Information System (INIS)

Brodsky, S.J.

1985-12-01

Hadronic and nuclear processes are covered, in which all final particles are measured at large invariant masses compared with each other, i.e., large momentum transfer exclusive reactions. Hadronic wave functions in QCD and QCD sum rule constraints on hadron wave functions are discussed. The question of the range of applicability of the factorization formula and perturbation theory for exclusive processes is considered. Some consequences of quark and gluon degrees of freedom in nuclei are discussed which are outside the usual domain of traditional nuclear physics. 44 refs., 7 figs

Lindhard's polarization parameter and atomic sum rules in the local plasma approximation

DEFF Research Database (Denmark)

Cabrera-Trujillo, R.; Apell, P.; Oddershede, J.

2017-01-01

In this work, we analyze the effects of Lindhard polarization parameter, χ, on the sum rule, Sp, within the local plasma approximation (LPA) as well as on the logarithmic sum rule Lp = dSp/dp, in both cases for the system in an initial excited state. We show results for a hydrogenic atom with nuc......In this work, we analyze the effects of Lindhard polarization parameter, χ, on the sum rule, Sp, within the local plasma approximation (LPA) as well as on the logarithmic sum rule Lp = dSp/dp, in both cases for the system in an initial excited state. We show results for a hydrogenic atom...... in terms of a screened charge Z* for the ground state. Our study shows that by increasing χ, the sum rule for p0 it increases, and the value p=0 provides the normalization/closure relation which remains fixed to the number of electrons for the same initial state. When p is fixed...

Faraday effect revisited: sum rules and convergence issues

DEFF Research Database (Denmark)

Cornean, Horia; Nenciu, Gheorghe

2010-01-01

This is the third paper of a series revisiting the Faraday effect. The question of the absolute convergence of the sums over the band indices entering the Verdet constant is considered. In general, sum rules and traces per unit volume play an important role in solid-state physics, and they give...

The generalized scheme-independent Crewther relation in QCD

Science.gov (United States)

Shen, Jian-Ming; Wu, Xing-Gang; Ma, Yang; Brodsky, Stanley J.

2017-07-01

The Principle of Maximal Conformality (PMC) provides a systematic way to set the renormalization scales order-by-order for any perturbative QCD calculable processes. The resulting predictions are independent of the choice of renormalization scheme, a requirement of renormalization group invariance. The Crewther relation, which was originally derived as a consequence of conformally invariant field theory, provides a remarkable connection between two observables when the β function vanishes: one can show that the product of the Bjorken sum rule for spin-dependent deep inelastic lepton-nucleon scattering times the Adler function, defined from the cross section for electron-positron annihilation into hadrons, has no pQCD radiative corrections. The ;Generalized Crewther Relation; relates these two observables for physical QCD with nonzero β function; specifically, it connects the non-singlet Adler function (Dns) to the Bjorken sum rule coefficient for polarized deep-inelastic electron scattering (CBjp) at leading twist. A scheme-dependent ΔCSB-term appears in the analysis in order to compensate for the conformal symmetry breaking (CSB) terms from perturbative QCD. In conventional analyses, this normally leads to unphysical dependence in both the choice of the renormalization scheme and the choice of the initial scale at any finite order. However, by applying PMC scale-setting, we can fix the scales of the QCD coupling unambiguously at every order of pQCD. The result is that both Dns and the inverse coefficient CBjp-1 have identical pQCD coefficients, which also exactly match the coefficients of the corresponding conformal theory. Thus one obtains a new generalized Crewther relation for QCD which connects two effective charges, αˆd (Q) =∑i≥1 αˆg1 i (Qi), at their respective physical scales. This identity is independent of the choice of the renormalization scheme at any finite order, and the dependence on the choice of the initial scale is negligible. Similar

Magnetic susceptibility and M1 transitions in /sup 208/Pb. [Sum rules

Energy Technology Data Exchange (ETDEWEB)

Traini, M; Lipparini, E; Orlandini, G; Stringari, S [Dipartimento di Matematica e Fisica, Universita di Trento, Italy

1979-04-16

M1 transitions in /sup 208/Pb are studied by evaluating energy-weighted and inverse energy-weighted sum-rules. The role of the nuclear interaction is widely discussed. It is shown that the nuclear potential increases the energy-weighted sum rule and lowers the inverse energy-weighted sum rule, with respect to the prediction of the pure shell model. Values of strengths and excitation energies are compared with experimental results and other theoretical calculations.

Sum rules for the real parts of nonforward current-particle scattering amplitudes

International Nuclear Information System (INIS)

Abdel-Rahman, A.M.M.

1976-01-01

Extending previous work, using Taha's refined infinite-momentum method, new sum rules for the real parts of nonforward current-particle scattering amplitudes are derived. The sum rules are based on covariance, casuality, scaling, equal-time algebra and unsubtracted dispersion relations for the amplitudes. A comparison with the corresponding light-cone approach is made, and it is shown that the light-cone sum rules would also follow from the assumptions underlying the present work

A sum rule description of giant resonances at finite temperature

International Nuclear Information System (INIS)

Meyer, J.; Quentin, P.; Brack, M.

1983-01-01

A generalization of the sum rule approach to collective motion at finite temperature is presented. The m 1 and msub(-1) sum rules for the isovector dipole and the isoscalar monopole electric modes have been evaluated with the modified SkM force for the 208 Pb nucleus. The variation of the resulting giant resonance energies with temperature is discussed. (orig.)

Dispersion relations and sum rules for natural optical activity

International Nuclear Information System (INIS)

Thomaz, M.T.; Nussenzveig, H.M.

1981-06-01

Dispersion relations and sum rules are derived for the complex rotatory power of an arbitrary linear (nonmagnetic) isotropic medium showing natural optical activity. Both previously known dispersion relations and sum rules as well as new ones are obtained. It is shown that the Rosenfeld-Condon dispersion formula is inconsistent with the expected asymptotic behavior at high frequencies. A new dispersion formula based on quantum eletro-dynamics removes this inconsistency; however, it still requires modification in the low-frequency limit. (Author) [pt

Sum rule approach to nuclear vibrations

International Nuclear Information System (INIS)

Suzuki, T.

1983-01-01

Velocity field of various collective states is explored by using sum rules for the nuclear current. It is shown that an irrotational and incompressible flow model is applicable to giant resonance states. Structure of the hydrodynamical states is discussed according to Tomonaga's microscopic theory for collective motions. (author)

Sum Rules of Charm CP Asymmetries beyond the SU(3)_{F} Limit.

Science.gov (United States)

Müller, Sarah; Nierste, Ulrich; Schacht, Stefan

2015-12-18

We find new sum rules between direct CP asymmetries in D meson decays with coefficients that can be determined from a global fit to branching ratio data. Our sum rules eliminate the penguin topologies P and PA, which cannot be determined from branching ratios. In this way, we can make predictions about direct CP asymmetries in the standard model without ad hoc assumptions on the sizes of penguin diagrams. We consistently include first-order SU(3)_{F} breaking in the topological amplitudes extracted from the branching ratios. By confronting our sum rules with future precise data from LHCb and Belle II, one will identify or constrain new-physics contributions to P or PA. The first sum rule correlates the CP asymmetries a_{CP}^{dir} in D^{0}→K^{+}K^{-}, D^{0}→π^{+}π^{-}, and D^{0}→π^{0}π^{0}. We study the region of the a_{CP}^{dir}(D^{0}→π^{+}π^{-})-a_{CP}^{dir}(D^{0}→π^{0}π^{0}) plane allowed by current data and find that our sum rule excludes more than half of the allowed region at 95% C.L. Our second sum rule correlates the direct CP asymmetries in D^{+}→K[over ¯]^{0}K^{+}, D_{s}^{+}→K^{0}π^{+}, and D_{s}^{+}→K^{+}π^{0}.

QCD contributions to vacuum polarization

International Nuclear Information System (INIS)

Reinders, L.J.; Rubinstein, H.R.; Yazaki, S.

1980-01-01

We have computed to lowest non-trivial order the perturbative and non-perturbative contributions to the vacuum polarization from all currents up to and including spin 2 ++ . These expressions are important, for example to evaluate QCD sum rules for heavy and light quark systems as shown by Shifman, Vainshtein and Zakharov. Most of the known ones are verified, one slightly changed, and many new ones are displayed. (orig.)

Higher-Twist Distribution Amplitudes of the K Meson in QCD

CERN Document Server

Ball, P; Lenz, A; Ball, Patricia

2006-01-01

We present a systematic study of twist-3 and twist-4 light-cone distribution amplitudes of the K meson in QCD. The structure of SU(3)-breaking corrections is studied in detail. Non-perturbative input parameters are estimated from QCD sum rules and renormalons. As a by-product, we give a complete reanalysis of the twist-3 and -4 parameters of the pi-meson distribution amplitudes; some of the results differ from those usually quoted in the literature.

Quasilocal quark models as effective theory of non-perturbative QCD

International Nuclear Information System (INIS)

Andrianov, A.A.

2006-01-01

We consider the Quasilocal Quark Model of NJL type (QNJLM) as effective theory of non-perturbative QCD including scalar (S), pseudo-scalar (P), vector (V) and axial-vector (A) four-fermion interaction with derivatives. In the presence of a strong attraction in the scalar channel the chiral symmetry is spontaneously broken and as a consequence the composite meson states are generated in all channels. With the help of Operator Product Expansion the appropriate set of Chiral Symmetry Restoration (CSR) Sum Rules in these channels are imposed as matching rules to QCD at intermediate energies. The mass spectrum and some decay constants for ground and excited meson states are calculated

Hadronic final states and sum rules in deep inelastic processes

International Nuclear Information System (INIS)

Pal, B.K.

1977-01-01

In order to get maximum information on the hadronic final states and sum rules in deep inelastic processes, Regge phenomenology and quarks parton model have been used. The unified picture for the production of hadrons of type i as a function of Bjorken and Feyman variables with only one adjustable parameter is formulated. The results of neutrino experiments and the production of charm particles are discussed in sum rules. (author)

Perturbative QCD and electromagnetic form factors

International Nuclear Information System (INIS)

Carlson, C.E.; Gross, F.

1987-01-01

We calculate nucleon magnetic form factors using perturbative QCD for several distribution amplitudes including a general one given in terms of Appell polynomials. We find that the magnitude and sign of both nucleon magnetic form factors can be explained within perturbative QCD. The observed normalization of G/sub Mp/ requires that the distribution amplitude be broader than its superhigh momentum transfer limit, and the G/sub Mn//G/sub Mp/ data may require the distribution amplitude to be asymmetric, in accord with distribution amplitudes derived from QCD sum rules. Some speculation as to how an asymmetric distribution amplitude can come about is offered. Finally, we show that the soft contributions corresponding to the particular distribution amplitudes we use need not be bigger than the data. 16 refs., 6 figs

Masses and couplings of open beauty states in QCD

International Nuclear Information System (INIS)

Rubinstein, H.R.; Reinders, L.J.; Yazaki, S.

1981-05-01

Masses and couplings of open beauty states (strange and non-strange) with Jsup(PC) = 0 ++ , 0 -+ , 1 -- . and 1 ++ are calculated using the QCD sum rule formalism. Non-perturbative effects due to quark and gluon condensate operators are shown to be important, confirming earlier calculations for equal quark mass systems. (author)

Derivation of sum rules for quark and baryon fields. [light-like charges

Energy Technology Data Exchange (ETDEWEB)

Bongardt, K [Karlsruhe Univ. (TH) (Germany, F.R.). Inst. fuer Theoretische Kernphysik

1978-08-21

In an analogous way to the Weinberg sum rules, two spectral-function sum rules for quark and baryon fields are derived by means of the concept of lightlike charges. The baryon sum rules are valid for the case of SU/sub 3/ as well as for SU/sub 4/ and the one-particle approximation yields a linear mass relation. This relation is not in disagreement with the normal linear GMO formula for the baryons. The calculated masses of the first resonance states agree very well with the experimental data.

Sum rules for four-spinon dynamic structure factor in XXX model

International Nuclear Information System (INIS)

Si Lakhal, B.; Abada, A.

2005-01-01

In the context of the antiferromagnetic spin 12 Heisenberg quantum spin chain (XXX model), we estimate the contribution of the exact four-spinon dynamic structure factor S 4 by calculating a number of sum rules the total dynamic structure factor S is known to satisfy exactly. These sum rules are: the static susceptibility, the integrated intensity, the total integrated intensity, the first frequency moment and the nearest-neighbor correlation function. We find that the contribution of S 4 is between 1% and 2.5%, depending on the sum rule, whereas the contribution of the exact two-spinon dynamic structure factor S 2 is between 70% and 75%. The calculations are numerical and Monte Carlo based. Good statistics are obtained

Dynamical local field, compressibility, and frequency sum rules for quasiparticles

International Nuclear Information System (INIS)

Morawetz, Klaus

2002-01-01

The finite temperature dynamical response function including the dynamical local field is derived within a quasiparticle picture for interacting one-, two-, and three-dimensional Fermi systems. The correlations are assumed to be given by a density-dependent effective mass, quasiparticle energy shift, and relaxation time. The latter one describes disorder or collisional effects. This parametrization of correlations includes local-density functionals as a special case and is therefore applicable for density-functional theories. With a single static local field, the third-order frequency sum rule can be fulfilled simultaneously with the compressibility sum rule by relating the effective mass and quasiparticle energy shift to the structure function or pair-correlation function. Consequently, solely local-density functionals without taking into account effective masses cannot fulfill both sum rules simultaneously with a static local field. The comparison to the Monte Carlo data seems to support such a quasiparticle picture

1S and $\\overline{MS}$ Bottom Quark Masses from $\\Upsilon$ Sum Rules

CERN Document Server

Hoang, A.H.

2000-01-01

The bottom quark $1S$ mass, $M_b^{1S}$, is determined using sum rules which relate the masses and the electronic decay widths of the $\\Upsilon$ mesons to moments of the vacuum polarization function. The $1S$ mass is defined as half the perturbative mass of a fictitious ${}^3S_1$ bottom-antibottom quark bound state, and is free of the ambiguity of order $\\Lambda_{QCD}$ which plagues the pole mass definition. Compared to an earlier analysis by the same author, which had been carried out in the pole mass scheme, the $1S$ mass scheme leads to a much better behaved perturbative series of the moments, smaller uncertainties in the mass extraction and to a reduced correlation of the mass and the strong coupling. We arrive at $M_b^{1S}=4.71\\pm 0.03$ GeV taking m_b(\\bar m_b)$ can be reduced if the three-loop corrections to the relation of pole and $\\bar{MS}$ mass are known and if the error in the strong coupling is decreased.

Second-moment sum rules for correlation functions in a classical ionic mixture

NARCIS (Netherlands)

Suttorp, L.G.; Ebeling, W.

1992-01-01

The complete set of second-moment sum rules for the correlation functions of arbitrarily high order describing a classical multi-component ionic mixture in equilibrium is derived from the grand-canonical ensemble. The connection of these sum rules with the large-scale behaviour of fluctuations in an

Two-particle lepton-nucleon processes in the dual QCD approach

International Nuclear Information System (INIS)

Bel'kov, A.A.

1984-01-01

The data on elastic and quasielastic lepton-nucleon scattering and on Δ 33 electro- and neutrino-production are analyzed in the dual approach based on finite-energy sum rules and QCD. A large class of two-particle lepton-nucleon processes at small and moderate momentum transfers 0.4 (GeV/c) 2 2 2 are described. It is shown that the data on these processes, used as an additional information, essentially decrease the ambiguity in determination of QCD parameters from analysis of deep inelastic lepton-nucleon scattering

Distributions of valence quarks in hadrons at small x in QCD

International Nuclear Information System (INIS)

Ioffe, B.L.; Kaidalov, A.B.

1984-01-01

Valence u- and d-quark distributions in nucleon and pion at small x (x=-q 2 /2ν is the fraction of the momentum carried by quarks) corresponding to rho and ω Regge pole exchange have been obtained on the basis of the QCD sum rule me-thod

Sum rule limitations of kinetic particle-production models

International Nuclear Information System (INIS)

Knoll, J.; CEA Centre d'Etudes Nucleaires de Grenoble, 38; Guet, C.

1988-04-01

Photoproduction and absorption sum rules generalized to systems at finite temperature provide a stringent check on the validity of kinetic models for the production of hard photons in intermediate energy nuclear collisions. We inspect such models for the case of nuclear matter at finite temperature employed in a kinetic regime which copes those encountered in energetic nuclear collisions, and find photon production rates which significantly exceed the limits imposed by the sum rule even under favourable concession. This suggests that coherence effects are quite important and the production of photons cannot be considered as an incoherent addition of individual NNγ production processes. The deficiencies of present kinetic models may also apply for the production of probes such as the pion which do not couple perturbatively to the nuclear currents. (orig.)

Continuum contributions to dipole oscillator-strength sum rules for hydrogen in finite basis sets

DEFF Research Database (Denmark)

Oddershede, Jens; Ogilvie, John F.; Sauer, Stephan P. A.

2017-01-01

Calculations of the continuum contributions to dipole oscillator sum rules for hydrogen are performed using both exact and basis-set representations of the stick spectra of the continuum wave function. We show that the same results are obtained for the sum rules in both cases, but that the conver......Calculations of the continuum contributions to dipole oscillator sum rules for hydrogen are performed using both exact and basis-set representations of the stick spectra of the continuum wave function. We show that the same results are obtained for the sum rules in both cases......, but that the convergence towards the final results with increasing excitation energies included in the sum over states is slower in the basis-set cases when we use the best basis. We argue also that this conclusion most likely holds also for larger atoms or molecules....

Bulk stress auto-correlation function in simple liquids-sum rules

International Nuclear Information System (INIS)

Tankeshwar, K.; Bhandari, R.; Pathak, K.N.

1990-10-01

Expressions for the zeroth, second and fourth frequency sum rules of the bulk stress auto correlation function have been derived. The exact expressions involve static correlation function up to four particles. Because of the non availability of any information about static quadruplet correlation function we use a low order decoupling approximation for this. In this work, we have obtained, separately, the sum rules for the different mechanism of momentum transfer in the fluids. The results are expected to be useful in the study of bulk viscosity of the fluids. (author). 9 refs

The Relation between the Electric Conductance of Nanostructure Bridge and Friedel Sum Rule

International Nuclear Information System (INIS)

Kotani, Y; Shima, N; Makoshi, K

2012-01-01

We analyze the electric conductance through nanostructure bridges in terms of phase-shifts, which satisfy the Friedel sum rule. The phase-shifts are given by solving the eigenvalue equation obtained by extending the method applied to a single impurity problem in a metal. The local charge neutrality condition is introduced through the Friedel sum rule. It is analytically shown that the electric conductance can increase as the two electrodes separate with the condition in which the phase-shifts satisfy the Friedel sum rule. The increment of the distance between two electrodes is obtained by gradually separating interatomic distance.

The spin structure function g1p of the proton and a test of the Bjorken sum rule

Directory of Open Access Journals (Sweden)

C. Adolph

2016-02-01

Full Text Available New results for the double spin asymmetry A1p and the proton longitudinal spin structure function g1p are presented. They were obtained by the COMPASS Collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH3 target. The data were collected in 2011 and complement those recorded in 2007 at 160 GeV, in particular at lower values of x. They improve the statistical precision of g1p(x by about a factor of two in the region x≲0.02. A next-to-leading order QCD fit to the g1 world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, ΔΣ, ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of g1p. The uncertainty of ΔΣ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function g1NS(x,Q2 yields as ratio of the axial and vector coupling constants |gA/gV|=1.22±0.05 (stat.±0.10 (syst., which validates the sum rule to an accuracy of about 9%.

Dense QCD in a Finite Volume

OpenAIRE

Yamamoto, Naoki; Kanazawa, Takuya

2009-01-01

We study the properties of QCD at high baryon density in a finite volume where color superconductivity occurs. We derive exact sum rules for complex eigenvalues of the Dirac operator at finite chemical potential, and show that the Dirac spectrum is directly related to the color superconducting gap $\\Delta$. Also, we find a characteristic signature of color superconductivity: an X-shaped spectrum of partition function zeros in the complex quark mass plane near the origin, reflecting the $Z(2)_...

Calculation of baryon sum rules and SU(4) mass formulae for mesons and baryons

International Nuclear Information System (INIS)

Bongardt, K.

1976-01-01

Light cone coordinates and field-field anticommutators for the free quark model on the light cone are introduced and light cone charges and light cone currents for the free quark model as well as sum rules for the meson and quark states are derived. The derivation of sum rules for the baryons is attempted. It is seen that it is possible formally to derive the same sum rules for the baryons and for the quarks. The baryon sums were derived through the symmetry properties of the baryon fields. Explicit assumptions about the spatial distribution of the three quarks in the baryons were not utilized. The meson-baryon Σ-terms, Zweig's rules in the SU (4) and a number of properties of the M-matrix are discussed. (BJ) [de

Slave-particle quantization and sum rules in the t-J model

International Nuclear Information System (INIS)

Le Guillou, J.C.; Ragoucy, E.

1994-12-01

In the framework of constrained systems, the classical Hamiltonian formulation of slave-particle models and their correct quantization are given. The electron-momentum distribution function in the t-J and Hubbard models is then studied in the framework of slave-particle approaches and within the decoupling scheme. It is shown that criticisms which have been addressed in this context coming from a violation of the sum rule for the physical electron are not valid. Due to the correct quantization rules for the slave-particles, the sum rule for the physical electron is indeed obeyed, both exactly and within the decoupling scheme. (author). 15 refs

Sum rules and moments for lepton-pair production. [Cross sections, Drell--Yan formula

Energy Technology Data Exchange (ETDEWEB)

Hwa, R.C.

1978-01-01

Sum rules on lepton-pair production cross sections are derived on the bases of the Drell--Yan formula and the known sum rules in leptoproduction. Also exact relations are obtained between the average transverse momenta squared of the valence quarks and moments of the dilepton cross sections. 12 references.

General solution of superconvergent sum rules for scattering of I=1 reggeons on baryons

International Nuclear Information System (INIS)

Grigoryan, A.A.; Khachatryan, G.N.

1986-01-01

Superconvergent sum rules for reggeon-particle scattering are applied to scattering of reggeons α i (i=π, ρ, A 2 ) with isospin I=1 on baryons with strangeness S=-1. The saturation scheme of these sum rules is determined on the basis of experimental data. Two series of baryon resonances with arbitrary isospins I and spins J=I+1/2 and J=I-1/2 are predicted. A general solution for vertices of interaction of these resonances with α i is found. Predictions for coupling vertices B α i B'(B, B'=Λ, Σ, Σ * ) agree well with the experiment. It is shown that the condition of sum rules saturation by minimal number of resonances brings to saturation schemes resulting from experimental data. A general solution of sum rules for scattering of α i reggeons on Ξ and Ω hyperons is analyzed

Chiral restoration and the extended photoabsorption sum rule in nuclei

International Nuclear Information System (INIS)

Ericson, M.; Rosa-Clot, M.; Kulagin, S.A.

1996-07-01

The Bethe-Levinger sum rule is extended beyond the potential model. The pion degrees of freedom are taken into account and the modifications of the potential theory are analyzed within two different approaches: dipole sum rule and dispersion relation on the Compton amplitude. Our aim is to extract from the photon data experimental information on the expectation value of the square of the pion field, a quantity which enters also in the restoration of chiral symmetry in nuclei and in pion-nucleus scattering. We are led to incorporate in the description the Δ resonance, which is strongly excited by the pion degrees of freedom

Chiral restoration and the extended photoabsorption sum rule in nuclei

Energy Technology Data Exchange (ETDEWEB)

Ericson, M [Lyon-1 Univ., 69 - Villeurbanne (France). Inst. de Physique Nucleaire; [European Organization for Nuclear Research, Geneva (Switzerland); Rosa-Clot, M [Florence Univ. (Italy). Ist. di Fisica; [Istituto Nazionale di Fisica Nucleare, Florence (Italy); Kulagin, S A [Akademiya Meditsinskikh Nauk SSSR, Moscow (Russian Federation)

1996-07-01

The Bethe-Levinger sum rule is extended beyond the potential model. The pion degrees of freedom are taken into account and the modifications of the potential theory are analyzed within two different approaches: dipole sum rule and dispersion relation on the Compton amplitude. Our aim is to extract from the photon data experimental information on the expectation value of the square of the pion field, a quantity which enters also in the restoration of chiral symmetry in nuclei and in pion-nucleus scattering. We are led to incorporate in the description the {Delta} resonance, which is strongly excited by the pion degrees of freedom. 11 refs.

Bottom mass from nonrelativistic sum rules at NNLL

Energy Technology Data Exchange (ETDEWEB)

Stahlhofen, Maximilian

2013-01-15

We report on a recent determination of the bottom quark mass from nonrelativistic (large-n) {Upsilon} sum rules with renormalization group improvement (RGI) at next-to-next-to-leading logarithmic (NNLL) order. The comparison to previous fixed-order analyses shows that the RGI computed in the vNRQCD framework leads to a substantial stabilization of the theoretical sum rule moments with respect to scale variations. A single moment fit (n=10) to the available experimental data yields M{sub b}{sup 1S}=4.755{+-}0.057{sub pert}{+-}0.009{sub {alpha}{sub s}}{+-}0.003{sub exp} GeV for the bottom 1S mass and anti m{sub b}(anti m{sub b})=4.235{+-}0.055{sub pert}{+-}0.003{sub exp} GeV for the bottom MS mass. The quoted uncertainties refer to the perturbative error and the uncertainties associated with the strong coupling and the experimental input.

The heat current density correlation function: sum rules and thermal conductivity

International Nuclear Information System (INIS)

Singh, Shaminder; Tankeshwar, K; Pathak, K N; Ranganathan, S

2006-01-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed

The heat current density correlation function: sum rules and thermal conductivity

Energy Technology Data Exchange (ETDEWEB)

Singh, Shaminder [Department of Physics, Panjab University, Chandigarh-160 014 (India); Tankeshwar, K [Department of Physics, Panjab University, Chandigarh-160 014 (India); Pathak, K N [Department of Physics, Panjab University, Chandigarh-160 014 (India); Ranganathan, S [Department of Physics, Royal Military College, Kingston, ON, K7K 7B4 (Canada)

2006-02-01

Expressions for the second and fourth sum rules of the heat current density correlation function have been derived in an appropriate ensemble. The thermal conductivity of Lennard-Jones fluids has been calculated using these sum rules for the heat current density correlation function and the Gaussian form of the memory function. It is found that the results obtained for the thermal conductivity are in good agreement with the molecular dynamics simulation results over a wide range of densities and temperatures. Earlier results obtained using the energy current density correlation function are also discussed.

The Adler sum rule and quark parton distribution functions in nucleon

International Nuclear Information System (INIS)

Niegawa, Akira; Sasaki, Ken.

1975-01-01

The behaviour of the quark parton distribution functions is discussed through the phenomenological analysis of the deep inelastic e-p and e-n data under constraint of the saturation of the Adler sum rule. It is concluded that in the region 0 0 where the Regge parametrization can be applied, anti u(x) is equal to anti d(x), and both behave as const/x, (x 0 will be 0.04--0.05); for x 0 x 0 is given. The rate of convergence of the Adler sum rule is also discussed. (auth.)

The generalized Crewther relation in QCD and its experimental consequences

International Nuclear Information System (INIS)

Brodsky, S.J.; Gabadadze, G.T.; Kataev, A.L.; Lu, H.J.

1995-12-01

We use the BLM scale-fixing prescription to derive a renormalization-scheme invariant relation between the coefficient function for the Bjorken sum rule for polarized deep inelastic scattering and the R-ratio for the e + e - annihilation cross section. This relation provides a generalization of the Crewther relation to non-conformally invariant gauge theories. The derived relations allow one to calculate unambiguously without renormalization scale or scheme ambiguity the effective charges of the polarized Bjorken and the Gross-Llewellen Smith sum rules from the experimental value for the effective charge associated with R-ratio. Present data are consistent with the generalized Crewther relations, but measurements at higher precision and energies will be needed to decisively test these fundamental relations in QCD. (orig.)

Measurement of xF3, F2 structure functions and Gross-Llewellyn Smith sum rule with IHEP-JINR neutrino detector

International Nuclear Information System (INIS)

Barabash, L.S.; Baranov, S.A.; Batusov, Yu.A.

1996-01-01

The isoscalar structure functions xF 3 and F 2 are measured as functions of x averaged over all Q 2 permissible for the range 6 to 28 GeV of incident (anti)neutrino energy. With the measured values of xF 3 , the value of the Gross-Llewellyn Smith sum rule is found to be ∫ 0 1 F 3 dx=2.13±0.38 (stat)±0.26 (syst). The QCD analysis of xF 3 provides Λ b ar M b ar S bar =358±59 MeV. The obtained value of the strong interaction constant α S (M Z )=0.120 -4 +3 is larger than most of the deep inelastic scattering results. 37 refs., 1 figs., 3 tabs

Limiting law excess sum rule for polyelectrolytes.

Science.gov (United States)

Landy, Jonathan; Lee, YongJin; Jho, YongSeok

2013-11-01

We revisit the mean-field limiting law screening excess sum rule that holds for rodlike polyelectrolytes. We present an efficient derivation of this law that clarifies its region of applicability: The law holds in the limit of small polymer radius, measured relative to the Debye screening length. From the limiting law, we determine the individual ion excess values for single-salt electrolytes. We also consider the mean-field excess sum away from the limiting region, and we relate this quantity to the osmotic pressure of a dilute polyelectrolyte solution. Finally, we consider numerical simulations of many-body polymer-electrolyte solutions. We conclude that the limiting law often accurately describes the screening of physical charged polymers of interest, such as extended DNA.

Lorentz-Lorenz quenching for the Gamow-Teller sum rule

International Nuclear Information System (INIS)

Delorme, J.; Ericson, M.; Figureau, A.

1984-03-01

We investigate the modification of the Gamow-Teller sum rule brought in by nucleonic excitations. The general trend of the data is well reproduced. The value of the force which mixes nucleonic and nuclear excitations is discussed

The black hole interior and a curious sum rule

International Nuclear Information System (INIS)

Giveon, Amit; Itzhaki, Nissan; Troost, Jan

2014-01-01

We analyze the Euclidean geometry near non-extremal NS5-branes in string theory, including regions beyond the horizon and beyond the singularity of the black brane. The various regions have an exact description in string theory, in terms of cigar, trumpet and negative level minimal model conformal field theories. We study the worldsheet elliptic genera of these three superconformal theories, and show that their sum vanishes. We speculate on the significance of this curious sum rule for black hole physics

The black hole interior and a curious sum rule

Energy Technology Data Exchange (ETDEWEB)

Giveon, Amit [Racah Institute of Physics, The Hebrew University,Jerusalem, 91904 (Israel); Itzhaki, Nissan [Physics Department, Tel-Aviv University,Ramat-Aviv, 69978 (Israel); Troost, Jan [Laboratoire de Physique Théorique,Unité Mixte du CRNS et de l’École Normale Supérieure,associée à l’Université Pierre et Marie Curie 6,UMR 8549 École Normale Supérieure,24 Rue Lhomond Paris 75005 (France)

2014-03-12

We analyze the Euclidean geometry near non-extremal NS5-branes in string theory, including regions beyond the horizon and beyond the singularity of the black brane. The various regions have an exact description in string theory, in terms of cigar, trumpet and negative level minimal model conformal field theories. We study the worldsheet elliptic genera of these three superconformal theories, and show that their sum vanishes. We speculate on the significance of this curious sum rule for black hole physics.

Sum rules in extended RPA theories

International Nuclear Information System (INIS)

Adachi, S.; Lipparini, E.

1988-01-01

Different moments m k of the excitation strength function are studied in the framework of the second RPA and of the extended RPA in which 2p2h correlations are explicitly introduced into the ground state by using first-order perturbation theory. Formal properties of the equations of motion concerning sum rules are derived and compared with those exhibited by the usual 1p1h RPA. The problem of the separation of the spurious solutions in extended RPA calculations is also discussed. (orig.)

Measurement of the neutron (³He) spin structure functions at low Q²: A connection between the Bjorken and gerasimov-drell-hearn sum rule

Energy Technology Data Exchange (ETDEWEB)

Djawotho, Pibero [College of William and Mary, Williamsburg, VA (United States)

2002-12-01

This dissertation presents results of experiment E94-010 performed at Jefferson Laboratory (simply known as JLab) in Hall A. The experiment aimed to measure the low Q² evolution of the Gerasimov-Drell-Hearn (GDH) integral from Q² = 0.1 to 0.9 GeV². The GDH sum rule at the real photon point provides an important test of Quantum Chromodynamics (QCD). The low Q² evolution of the GDH integral contests various resonance models, Chiral Perturbation Theory ({chi} PT) and lattice QCD calculations, but more importantly, it helps us understand the transition between partonic and hadronic degrees of freedom. At high Q², beyond 1 GeV², the difference of the GDH integrals for the proton and the neutron is related to the Bjorken sum rule, another fundamental test of QCD. In addition, results of the measurements for the spin structure functions g₁ and g₂, cross sections, and asymmetries are presented. E94-010 was the first experiment of its kind at JLab. It used a high-pressure, polarized ³He target with a gas pressure of 10 atm and average target polarization of 35%. For the first time, the polarized electron source delivered an average beam polarization of 70% with a beam current of 15 micro A. The limit on the beam current was only imposed by the target. The experiment required six different beam energies from 0.86 to 5.1 GeV. This was the first time the accelerator ever reached 5.1 GeV. Both High-Resolution Spectrometers of Hall A, used in singles mode, were positioned at 15.5 ° each.

Sum rules for charge transition density

Energy Technology Data Exchange (ETDEWEB)

Gul' karov, I S [Tashkentskij Politekhnicheskij Inst. (USSR)

1979-01-01

The form factors of the quadrupole and octupole oscillations of the /sup 12/C nucleus are compared with the predictions of the sum rules for the charge transition density (CTD). These rules allow one to obtain various CTDs which contain the components k: r/sup lambda + 2k-2/rho(r) and r/sup lambda + 2k-1)(drho(r)/dr) (k = 0, 1, 2...) and can be applied to analyze the inelastic scattering of high energy particles by nuclei. It is shown that the CTD under consideration have different radius dependence and describe the data essentially better (though ambiguously) than the Tassy and Steinwedel-Jensen models do. Recurrence formulas are derived for the ratios of the higher-order transition matrix elements and CTD. These formulas can be used to predict the CTD behavior for highly excited nuclear states.

A self-consistent semiclassical sum rule approach to the average properties of giant resonances

International Nuclear Information System (INIS)

Li Guoqiang; Xu Gongou

1990-01-01

The average energies of isovector giant resonances and the widths of isoscalar giant resonances are evaluated with the help of a self-consistent semiclassical Sum rule approach. The comparison of the present results with the experimental ones justifies the self-consistent semiclassical sum rule approach to the average properties of giant resonances

Two-particle lepton--nucleon processes in the dual QCD approach

International Nuclear Information System (INIS)

Bel'kov, A.A.; Ivanov, Y.P.; Kovalenko, S.G.

1984-01-01

Using a dual approach based on finite-energy sum rules and QCD, an analysis is made of data on elastic and quasielastic lepton--nucleon scattering and on the reactions of electron- and neutrino-induced production of the Δ 33 isobar. A description is obtained of a wide range of two-particle lepton--nucleon processes in the region of small and moderate momentum transfers 0.4 (GeV/c) 2 2 2 . It is shown that the use of data on these processes as additional information substantially reduces the ambiguity in the determination of the QCD parameters in the analysis of deep inelastic lepton--nucleon scattering

O(N) symmetries, sum rules for generalized Hermite polynomials and squeezed states

International Nuclear Information System (INIS)

Daboul, Jamil; Mizrahi, Salomon S

2005-01-01

Quantum optics has been dealing with coherent states, squeezed states and many other non-classical states. The associated mathematical framework makes use of special functions as Hermite polynomials, Laguerre polynomials and others. In this connection we here present some formal results that follow directly from the group O(N) of complex transformations. Motivated by the squeezed states structure, we introduce the generalized Hermite polynomials (GHP), which include as particular cases, the Hermite polynomials as well as the heat polynomials. Using generalized raising operators, we derive new sum rules for the GHP, which are covariant under O(N) transformations. The GHP and the associated sum rules become useful for evaluating Wigner functions in a straightforward manner. As a byproduct, we use one of these sum rules, on the operator level, to obtain raising and lowering operators for the Laguerre polynomials and show that they generate an sl(2, R) ≅ su(1, 1) algebra

Sum rule approach to the nuclear response in the isovector spin channel

International Nuclear Information System (INIS)

Alberico, W.M.; Ericson, M.; Molinari, A.

1982-01-01

We study the global features of the response of infinite nuclear matter in the spin-isospin channel through the energy weighted sum rules S 1 and Ssub(-) 1 . In particular we compare the outcome of the ring approximation with the exact RPA evaluation of the sum rules. We also investigate the influence of the collective character of the response, induced by the particle hole force for a longitudinal and transverse spin couplings. We show that S 1 is insensitive to the collectivity of the response, as long as the Δ degree of freedom is ignored. The inverse energy weighted sum rule on the other hand, which is linked to the paramagnetic susceptibility, always reflects the hardening or softening of the nuclear response, due to the repulsive or attractive character of the p-h force. This quantity is well suited to the comparison with the experiments, which we perform for 12 C and 56 Fe. (orig.)

Parton model (Moessbauer) sum rules for b → c decays

International Nuclear Information System (INIS)

Lipkin, H.J.

1993-01-01

The parton model is a starting point or zero-order approximation in many treatments. The author follows an approach previously used for the Moessbauer effect and shows how parton model sum rules derived for certain moments of the lepton energy spectrum in b → c semileptonic decays remain valid even when binding effects are included. The parton model appears as a open-quote semiclassical close-quote model whose results for certain averages also hold (correspondence principle) in quantum mechanics. Algebraic techniques developed for the Moessbauer effect exploit simple features of the commutator between the weak current operator and the bound state Hamiltonian to find the appropriate sum rules and show the validity of the parton model in the classical limit, ℎ → 0, where all commutators vanish

Sum-rule analysis of long-wavelength excitations in electron liquids

International Nuclear Information System (INIS)

Ichimaru, Setsuo; Totsuji, Hiroo; Tange, Toshio; Pines, D.

1975-01-01

The properties of the plasma oscillations, the single-particle excitations and the collisional excitations in the classical one-component plasma are investigated in the long-wave-length domain with the aid of moment sum rules. The frequency moments of the dynamic form factor are calculated up to that term which involves the ternary correlation function. The dispersion in the plasma-wave frequency and the strengths of the single-particle and collisional excitations are computed over the thermodynamically stable domain of the plasma parameter, epsilon<=10. It is emphasized that inclusion of the collisional excitations plays a vital part in satisfying various moment-sum rules and in securing agreement with known boundary conditions such as the Vlasov description and molecular-dynamics computations. (auth.)

Meson widths and form factor at intermediate momentum transfer in nonperturbative QCD

International Nuclear Information System (INIS)

Ioffe, B.L.; Smilga, A.V.

1982-01-01

A general method is proposed for the QCD based calculations of form factors at intermediate momentum transfer Q 2 and of the partial widths of the low-lying meson resonances. The basic idea is to use the QCD sum rules for the vertex functions. With this method the pion electromagnetic form factor along with electromagnetic form factors of rho- and A 1 mesons and transition form factors γπ → A 1 at 0.5 2 2 are calculated. The widths rho+2π and A 1 → rhoπ are also determined. +.he results are in a good agreement with experiment

Experimental check of the GDH sum rule at MAMI and ELSA

International Nuclear Information System (INIS)

Krimmer, J.

2002-01-01

The experimental check of the GDH sum rule is being performed at the tagged photon facilities of the electron accelerators MAMI (Mainz) and ELSA (Bonn), using circularly polarized photons impinging on a longitudinally polarized proton target, together with detector systems covering almost the whole solid angle range. Results from the MAMI experiment for the double polarized total photoabsorption cross section in the low energy region (200 MeV < Eγ < 800 MeV) will be shown together with their contribution to the GDH sum rule. Furthermore first results from the ELSA experiment in the higher energy region (680 MeV < Eγ < 1900 MeV) will be presented

Light Cone Sum Rules for gamma*N ->Delta Transition Form Factors

Energy Technology Data Exchange (ETDEWEB)

V.M. Braun; A. Lenz; G. Peters; A. Radyushkin

2006-02-01

A theoretical framework is suggested for the calculation of {gamma}* N {yields} {Delta} transition form factors using the light-cone sum rule approach. Leading-order sum rules are derived and compared with the existing experimental data. We find that the transition form factors in a several GeV region are dominated by the ''soft'' contributions that can be thought of as overlap integrals of the valence components of the hadron wave functions. The ''minus'' components of the quark fields contribute significantly to the result, which can be reinterpreted as large contributions of the quark orbital angular momentum.

Form factors and QCD in spacelike and timelike region

International Nuclear Information System (INIS)

A.P. Bakulev; A.V. Radyushkin; N.G. Stefanis

2000-01-01

The authors analyze the basic hard exclusive processes: πγ * γ-transition, pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 > 0 of the relevant momentum transfers. They describe the construction of the timelike version of the coupling constant α s . They show that due to the analytic continuation of the collinear logarithms each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. They found no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, they use a QCD sum rule inspired model and show that there are non-canceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region

Form factors and QCD in spacelike and timelike regions

International Nuclear Information System (INIS)

Bakulev, A. P.; Radyushkin, A. V.; Stefanis, N. G.

2000-01-01

We analyze the basic hard exclusive processes, the πγ * γ-transition and the pion and nucleon electromagnetic form factors, and discuss the analytic continuation of QCD formulas from the spacelike q 2 2 >0 of the relevant momentum transfers. We describe the construction of the timelike version of the coupling constant α s . We show that due to the analytic continuation of the collinear logarithms, each eigenfunction of the evolution equation acquires a phase factor and investigate the resulting interference effects which are shown to be very small. We find no sources for the K-factor-type enhancements in the perturbative QCD contribution to the hadronic form factors. To study the soft part of the pion electromagnetic form factor, we use a QCD sum rule inspired model and show that there are noncanceling Sudakov double logarithms which result in a K-factor-type enhancement in the timelike region

Uses of dipole oscillator strength sum rules in second order perturbation theory

International Nuclear Information System (INIS)

Struensee, M.C.

1984-01-01

Certain moments of the dipole oscillator strength distribution of atoms and molecules can be calculated from theory (using sum rules) or deduced from experiment. The present work describes the use of these moments to construct effective distributions which lead to bounds and estimates of physical properties of interest. Asymptotic analysis is then used to obtain the high energy behavior of the oscillator strength density and a previously unknown sum rule for atoms and molecules. A new type of effective distribution, which incorporates the information concerning the asymptotic behavior and the new sum rule, is suggested. This new type of distribution is used to calculate the logarithmic mean excitation energies for the ground states of atomic hydrogen, atomic helium and the negative hydrogen ion. The calculations for atomic helium and the negative hydrogen ion require the evaluation of certain ground state expectation values. These have been calculated using high accuracy wavefunctions containing the nonconventional terms shown by Fock to be necessary for a correct analytic expansion when both electrons are near the nucleus

The Bethe Sum Rule and Basis Set Selection in the Calculation of Generalized Oscillator Strengths

DEFF Research Database (Denmark)

Cabrera-Trujillo, Remigio; Sabin, John R.; Oddershede, Jens

1999-01-01

Fulfillment of the Bethe sum rule may be construed as a measure of basis set quality for atomic and molecular properties involving the generalized oscillator strength distribution. It is first shown that, in the case of a complete basis, the Bethe sum rule is fulfilled exactly in the random phase...

Tracing back resonances to families of Regge trajectories. New finite energy sum rules

International Nuclear Information System (INIS)

Mandelbrojt, Jacques.

1975-04-01

An amplitude is supposed to be expressed for large enough energies as a sum of contributions of Regge poles. Calling family of trajectories the set of trajectories which differ by integers from one of them, a correspondance, such that the energy and width of a given resonance depend on only family of trajectories, is established between resonances of the amplitude and families of trajectories. The contribution to the amplitude of each family of trajectories is shown to satisfy the same finite energy sum rules as does the amplitude itself. In these sum rules the resonance approximation can be made where the only resonances that will appear are those which are in correspondence with the family [fr

The Gauge-Invariant Angular Momentum Sum-Rule for the Proton

CERN Document Server

Shore, G.M.

2000-01-01

We give a gauge-invariant treatment of the angular momentum sum-rule for the proton in terms of matrix elements of three gauge-invariant, local composite operators. These matrix elements are decomposed into three independent form factors, one of which is the flavour singlet axial charge. We further show that the axial charge cancels out of the sum-rule, so that it is unaffacted by the axial anomaly. The three form factors are then related to the four proton spin components in the parton model, namely quark and gluon intrinsic spin and orbital angular momentum. The renormalisation of the three operators is determined to one loop from which the scale dependence and mixing of the spin components is derived under the constraint that the quark spin be scale-independent. We also show how the three form factors can be measured in experiments.

The Thomas-Reiche-Kuhn sum rule and the toroid moments

International Nuclear Information System (INIS)

Dubovik, V.M.

1975-01-01

By example of the Thomas-Reiche-Kuhn sum rule a procedure is given for calculating the retardation effects in any E-transition strengths via the toroid moments. The investigation has been performed at the Laboratory of Theoretical Physics, JINR

Spin structure of the neutron ({sup 3}He) and the Bjoerken sum rule

Energy Technology Data Exchange (ETDEWEB)

Meziani, Z.E. [Stanford Univ., CA (United States)

1994-12-01

A first measurement of the longitudinal asymmetry of deep-inelastic scattering of polarized electrons from a polarized {sup 3}He target at energies ranging from 19 to 26 GeV has been performed at the Stanford Linear Accelerator Center (SLAC). The spin-structure function of the neutron g{sub 1}{sup n} has been extracted from the measured asymmetries. The Quark Parton Model (QPM) interpretation of the nucleon spin-structure function is examined in light of the new results. A test of the Ellis-Jaffe sum rule (E-J) on the neutron is performed at high momentum transfer and found to be satisfied. Furthermore, combining the proton results of the European Muon Collaboration (EMC) and the neutron results of E-142, the Bjoerken sum rule test is carried at high Q{sup 2} where higher order Perturbative Quantum Chromodynamics (PQCD) corrections and higher-twist corrections are smaller. The sum rule is saturated to within one standard deviation.

Pion form factor in QCD at intermediate momentum transfers

Science.gov (United States)

Braun, V. M.; Khodjamirian, A.; Maul, M.

2000-04-01

We present a quantitative analysis of the electromagnetic pion form factor in the light-cone sum rule approach, including radiative corrections and higher-twist effects. The comparison to the existing data favors the asymptotic profile of the pion distribution amplitude and allows us to estimate the deviation: [∫du/uφπ(u)]/[∫du/uφasπ(u)]=1.1+/-0.1 at the scale of 1 GeV. Special attention is paid to the precise definition and interplay of soft and hard contributions at intermediate momentum transfer, and to the matching of the sum rule to the perturbative QCD prediction. We observe a strong numerical cancellation between the soft (end-point) contribution and power-suppressed hard contributions of higher twist, so that the total nonperturbative correction to the usual PQCD result turns out to be of the order of 30% for Q2~1 GeV2.

A simple derivation of new sum rules of Bessel functions

International Nuclear Information System (INIS)

Ciocci, F.; Dattoli, G.; Dipace, A.

1985-01-01

In this note it is exploited a recently suggested technique to get simple expressions for a class of sum rules of Bessel functions appearing in plasma physics; their relevance to the numerical evaluation of the Turkin function is also discussed

Radiative E1-decay of charmonium 1P1 level within sum rules of quantum chromodynamics

International Nuclear Information System (INIS)

Martynenko, A.P.

1991-01-01

Analysis of radiative decay of 1 P 1 → 1 S 0 + γ charmonium within sum rules of quantum chromodynamics was conducted. The sum rule, taking account of gluon exponential correction, was obtained, and width of Χ → η c + γ decay was calculated

Nucleon wave function from lattice QCD

International Nuclear Information System (INIS)

Warkentin, Nikolaus

2008-04-01

In this work we develop a systematic approach to calculate moments of leading-twist and next-to-leading twist baryon distribution amplitudes within lattice QCD. Using two flavours of dynamical clover fermions we determine low moments of nucleon distribution amplitudes as well as constants relevant for proton decay calculations in grand unified theories. The deviations of the leading-twist nucleon distribution amplitude from its asymptotic form, which we obtain, are less pronounced than sometimes claimed in the literature. The results are applied within the light cone sum rule approach to calculate nucleon form factors that are compared with recent experimental data. (orig.)

Nucleon wave function from lattice QCD

Energy Technology Data Exchange (ETDEWEB)

Warkentin, Nikolaus

2008-04-15

In this work we develop a systematic approach to calculate moments of leading-twist and next-to-leading twist baryon distribution amplitudes within lattice QCD. Using two flavours of dynamical clover fermions we determine low moments of nucleon distribution amplitudes as well as constants relevant for proton decay calculations in grand unified theories. The deviations of the leading-twist nucleon distribution amplitude from its asymptotic form, which we obtain, are less pronounced than sometimes claimed in the literature. The results are applied within the light cone sum rule approach to calculate nucleon form factors that are compared with recent experimental data. (orig.)

On sum rules for charge transition density

International Nuclear Information System (INIS)

Gul'karov, I.S.

1979-01-01

The form factors of the quadrupole and octupole oscillations of the 12 C nucleus are compared with the predictions of the sum rules for the charge transition density (CTD). These rules allow to obtain various CTD which contain the components k: rsup(lambda+2k-2)rho(r) and rsup(lambda+2k-1)(drho(r)/dr) (k=0, 1, 2...) and can be applied to analyze the inelastic scattering of high energy particles by nuclei. It is shown that the CTD under consideration have different radius dependence and describe the data essentially better (though ambiguously) than the Tassy and Steinwedel-Jensen models do. The recurrent formulas are derived for the ratios of the higher order transition matrix elements and CTD. These formulas can be used to predict the CTD behaviour for highly excited nuclear states

Borel sum rules for octet baryons in nuclear medium

International Nuclear Information System (INIS)

Kondo, Y.; Morimatsu, O.

1992-06-01

Borel sum rules are examined for octet baryons in the nuclear medium. First, it is noticed that in the medium the dispersion relation is realized for the retarded correlation Π R (ω, q 2 ) in the energy ω. Then, Π R (ω, q 2 ) is split into even and odd parts of ω in order to apply the Borel transformation. The obtained Borel sum rules differ from those of previous works. The mass shifts of octet baryons are calculated in the leading order of the operator product expansion with linear density approximation for the condensates. It is found that both scalar and vector condensates of the quark field, and + q>, induce attraction to the octet baryons in the medium in contrast to the results of previous works. It is also found that |δM N | > |δM Λ | > |δM Σ | ∼ |δM Ξ |. The absolute values, however, turn out to be one order of magnitude larger than those empirically known if a Borel mass of around 1 GeV is used in the present approximation. (author)

Sum rules for elements of flavor-mixing matrices based on a non-semisimple symmetry

International Nuclear Information System (INIS)

Sogami, Ikuo S.

2006-01-01

Sum rules for elements of flavor-mixing matrices (FMMs) are derived within a new algebraic theory for flavor physics, in which the FMMs are identified with elements of the Lie group isomorphic to SU(2) x U(1). The resulting sum rules originating from the unique elaborate structure of the algebra of the group are so simple and explicit that their validity can be confirmed by analyzing properly processed experimental data. (author)

A new sum rule relating the deep-inelastic polarized structure function to the cross section of photoproduction

International Nuclear Information System (INIS)

Koretune, Susumu

1993-01-01

A sum rule which relates the deep-inelastic polarized structure function g 1 p (x,Q 2 ) to the cross section of photoproduction, (σ 3/2 -σ 1/2 ), is derived. This rule makes it possible to compare the integral of g 1 p (x,Q 2 ) with the Drell-Hearn-Gerasimov sum rule without worrying about contributions from higher twist terms. Further this sum rule shows that there may exist a dynamical mechanism which relates the low energy region to the high energy one. It is conjectured that the spontaneous chiral symmetry breaking of the vacuum is the origin of this mechanism. (author)

Charge symmetry breaking in spin dependent parton distributions and the Bjorken sum rule

International Nuclear Information System (INIS)

Cloet, I.C.; Horsley, R.; Londergan, J.T.

2012-04-01

We present the rst determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the rst two Mellin moments of the spin-dependent parton distribution functions of the octet baryons from N f =2+1 lattice simulations. The results are compared with predictions from quark models of nucleon structure. We discuss the contribution of partonic spin CSV to the Bjorken sum rule, which is important because the CSV contributions represent the only partonic corrections to the Bjorken sum rule.

Charge symmetry breaking in spin dependent parton distributions and the Bjorken sum rule

Energy Technology Data Exchange (ETDEWEB)

Cloet, I.C. [Adelaide Univ, SA (Australia). CSSM, School of Chemistry and Physics; Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Londergan, J.T. [Indiana Univ., Bloomington, IN (US). Dept. of Physics and Center for Exploration of Energy and Matter] (and others)

2012-04-15

We present the rst determination of charge symmetry violation (CSV) in the spin-dependent parton distribution functions of the nucleon. This is done by determining the rst two Mellin moments of the spin-dependent parton distribution functions of the octet baryons from N{sub f}=2+1 lattice simulations. The results are compared with predictions from quark models of nucleon structure. We discuss the contribution of partonic spin CSV to the Bjorken sum rule, which is important because the CSV contributions represent the only partonic corrections to the Bjorken sum rule.

Isospin sum rule for nuclear photoabsorption: Effect of retardation

International Nuclear Information System (INIS)

Maize, M.A.; Fallieros, S.

1987-01-01

Motivated by the close similarity between a sum rule originally derived by Cabibbo and Radicati and a simplified version based on nonrelativistic nuclear physics in the long-wavelength limit, we have investigated the effect of retardation corrections. An account of the contributions due to higher multipolarities is presented, together with a physical interpretation of the results

A convergent reformulation of perturbative QCD

International Nuclear Information System (INIS)

Alves, R.J.G.

2000-10-01

We present and explore a new formulation of perturbative QCD based not on the renormalised coupling but on the dimensional transmutation parameter of the theory and the property of asymptotic scaling. The approach yields a continued function, the iterated function being that involved in the solution of the two-loop β-function equation. In the so-called large-b limit the continued function reduces to a continued fraction and the successive approximants are diagonal Pade approximants. We investigate numerically the convergence of successive approximants using the leading-b approximation, motivated by renormalons, to model the all-orders result. We consider the Adler D-function of vacuum polarisation, the Polarised Bjorken and Gross-LIewellyn Smith sum rules, the (unpolarised) Bjorken sum rule, and the Minkowskian quantities R τ and the R-ratio of e + e - annihilation. In contrast to diagonal Pade approximants the truncated continued function method gives remarkably stable large-order approximants in cases where infrared renormalon effects are important. We also use the new approach to determine the QCD fundamental parameters from the R τ and the R-ratio measurements, where we find Λ-tilde (3)/MS = 516 ± 48 MeV (which yields α s (μ = m τ ) = 0.360 -0.020 +0.021 ), and Λ-tilde (5)/MS = 299 -7 +6 MeV (which yields α s (μ = m z 0 ) = 0.1218 ± 0.0004), respectively. The evolution of the former value to the m z 0 energy results in α s (μ = m z 0 ) = 0.123 ± 0.002. These values are in line with other determinations available in the literature. We implement the Complete Renormalisation Group Improvement (CORGI) scheme throughout all the calculations. We report on how the mathematical concept of Stieltjes series can be used to assess the convergence of Pade approximants of perturbative series. We find that the combinations of UV renormalons which occur in perturbative QCD may or may not be Stieltjes series depending on the renormalisation scheme used. (author)

Magnetic dipole moments of the heavy tensor mesons in QCD

Energy Technology Data Exchange (ETDEWEB)

Aliev, T. M., E-mail: taliev@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T., E-mail: tbarakat@KSU.EDU.SA [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Physics and Astronomy Department, King Saud University, Riyadh (Saudi Arabia); Savcı, M., E-mail: savci@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey)

2015-11-03

The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors.

Magnetic dipole moments of the heavy tensor mesons in QCD

Energy Technology Data Exchange (ETDEWEB)

Aliev, T.M. [Middle East Technical University, Physics Department, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T. [Middle East Technical University, Physics Department, Ankara (Turkey); King Saud University, Physics and Astronomy Department, Riyadh (Saudi Arabia); Savci, M. [Middle East Technical University, Physics Department, Ankara (Turkey)

2015-11-15

The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors. (orig.)

Nucleon magnetic moments and magnetic properties of vacuum in QCD

International Nuclear Information System (INIS)

Ioffe, B.L.; Smilga, A.V.

1983-01-01

Magnetic moments of a proton and a neutron are calculated in the QCD sum rule approach. The substantial role of the external electromagnetic field induced vacuum expectation values, the most important of which is connected with quark condensate magnetic susceptibility, is demonstrated. The results are μsub(p)=3.0, μsub(n)=2.0(+-10%) that is in a perfect agreement with experiment. The invariant amplitudes of Δ→pγ transition are also calculated

Various versions of analytic QCD and skeleton-motivated evaluation of observables

International Nuclear Information System (INIS)

Cvetic, Gorazd; Valenzuela, Cristian

2006-01-01

We present skeleton-motivated evaluation of QCD observables. The approach can be applied in analytic versions of QCD in certain classes of renormalization schemes. We present two versions of analytic QCD which can be regarded as low-energy modifications of the ''minimal'' analytic QCD and which reproduce the measured value of the semihadronic τ decay ratio r τ . Further, we describe an approach of calculating the higher-order analytic couplings A k (k=2,3,...) on the basis of logarithmic derivatives of the analytic coupling A 1 (Q 2 ). This approach can be applied in any version of analytic QCD. We adjust the free parameters of the aforementioned two analytic models in such a way that the skeleton-motivated evaluation reproduces the correct known values of r τ and of the Bjorken polarized sum rule (BjPSR) d b (Q 2 ) at a given point (e.g., at Q 2 =2 GeV 2 ). We then evaluate the low-energy behavior of the Adler function d v (Q 2 ) and the BjPSR d b (Q 2 ) in the aforementioned evaluation approach, in the three analytic versions of QCD. We compare with the results obtained in the minimal analytic QCD and with the evaluation approach of Milton et al. and Shirkov

More sum rules for quark and lepton masses

International Nuclear Information System (INIS)

Terazawa, Hidezumi.

1990-04-01

Sum rules for quark and lepton masses are derived from the Ward identity of Chanowitz and Ellis for the vertex function of the trace of the energy-momentum tensor and the two axial-vector currents and the partially conserved axial-vector current hypothesis. They indicate, among other things, that the constituent quark masses of u and d and those of the techniquarks, if any, are about 300 MeV and 300 GeV, respectively. (author)

Predictions for the Dirac C P -violating phase from sum rules

Science.gov (United States)

Delgadillo, Luis A.; Everett, Lisa L.; Ramos, Raymundo; Stuart, Alexander J.

2018-05-01

We explore the implications of recent results relating the Dirac C P -violating phase to predicted and measured leptonic mixing angles within a standard set of theoretical scenarios in which charged lepton corrections are responsible for generating a nonzero value of the reactor mixing angle. We employ a full set of leptonic sum rules as required by the unitarity of the lepton mixing matrix, which can be reduced to predictions for the observable mixing angles and the Dirac C P -violating phase in terms of model parameters. These sum rules are investigated within a given set of theoretical scenarios for the neutrino sector diagonalization matrix for several known classes of charged lepton corrections. The results provide explicit maps of the allowed model parameter space within each given scenario and assumed form of charged lepton perturbations.

QCD and resonance physics. The π-p-A1 system

International Nuclear Information System (INIS)

Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.

1978-01-01

The QCD sum rules derived earlier are applied to evaluate the leptonic widths and masses of the π, rho, A 1 mesons (the very existence of resonances is taken as granted, however). The mass scale is set by the power corrections to asymptotic freedom which are due to nonperturbative effects in QCD. The main results are expressions for the p → e + e - and π → μν decay widths and a relation between the mass and the power corrections. Estimates of the A 1 leptonic width are also presented. It is argued that the observed difference in the spectra in the in the vector and axial-vector channels (π - rho - A 1 system) provides a very clean test of the power corrections

Next-to-next-to-leading order QCD analysis of combined data for xF3 structure function and higher-twist contribution

International Nuclear Information System (INIS)

Sidorov, A.V.

1996-01-01

The simultaneous QCD analysis of the xF 3 structure function measured in deep-inelastic scattering by several collaborations is done up to 3-loop order of QCD. The x dependence of the higher-twist contribution is evaluated and turns out to be in a qualitative agreement with the results of 'old' CCFR data analysis and with renormalon approach predictions. The Gross-Llewellyn Smith sum rule and its higher-twist corrections are evaluated. 32 refs., 1 figs., 1 tab

Experimental check of the Gerasimov-Drell-Hearn sum rule for H1

International Nuclear Information System (INIS)

Dutz, H.; Drachenfels, W. von; Frommberger, F.; Hillert, W.; Klein, F.; Menze, D.; Rohlof, C.; Schoch, B.; Helbing, K.; Speckner, T.; Zeitler, G.; Anton, G.; Bock, A.; Godo, M.; Kiel, B.; Michel, T.; Naumann, J.; Krimmer, J.; Grabmayr, P.; Sauer, M.

2004-01-01

For the first time we checked the fundamental Gerasimov-Drell-Hearn (GDH) sum rule for the proton experimentally in the photon energy range from 0.2-2.9 GeV with the tagged photon facilities at MAMI (Mainz) and ELSA (Bonn). New data of the doubly polarized total cross section difference are presented in the energy range from 1.6 to 2.9 GeV. The contribution to the GDH integral from 0.2-2.9 GeV yields [254±5(stat)±12(syst)] μb with negative contributions in the Regge regime at photon energies above 2.1 GeV. This trend supports the validity of the GDH sum rule

The Spin-dependent Structure Function of the Proton $g_{1}^p$ and a Test of the Bjorken Sum Rule

CERN Document Server

Alekseev, M.G.; Alexandrov, Yu.; Alexeev, G.D.; Amoroso, A.; Austregesilo, A.; Badelek, B.; Balestra, F.; Ball, J.; Barth, J.; Baum, G.; Bedfer, Y.; Bernhard, J.; Bertini, R.; Bettinelli, M.; Birsa, R.; Bisplinghoff, J.; Bordalo, P.; Bradamante, F.; Bravar, A.; Bressan, A.; Brona, G.; Burtin, E.; Bussa, M.P.; Chaberny, D.; Cotic, D.; Chiosso, M.; Chung, S.U.; Cicuttin, A.; Colantoni, M.; Crespo, M.L.; Dalla Torre, S.; Das, S.; Dasgupta, S.S.; Denisov, O.Yu.; Dhara, L.; Diaz, V.; Donskov, S.V.; Doshita, N.; Duic, V.; Dunnweber, W.; Efremov, A.; El Alaoui, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Filin, A.; Finger, M.; Finger, M., Jr.; Fischer, H.; Franco, C.; Friedrich, J.M.; Garfagnini, R.; Gautheron, F.; Gavrichtchouk, O.P.; Gazda, R.; Gerassimov, S.; Geyer, R.; Giorgi, M.; Gnesi, I.; Gobbo, B.; Goertz, S.; Grabmuller, S.; Grasso, A.; Grube, B.; Gushterski, R.; Guskov, A.; Haas, F.; von Harrach, D.; Hasegawa, T.; Heinsius, F.H.; Hermann, R.; Herrmann, F.; Hess, C.; Hinterberger, F.; Horikawa, N.; Hoppner, Ch.; d'Hose, N.; Ilgner, C.; Ishimoto, S.; Ivanov, O.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jasinski, P.; Jegou, G.; Joosten, R.; Kabuss, E.; Kafer, W.; Kang, D.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu.A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koblitz, S.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konopka, R.; Konorov, I.; Konstantinov, V.F.; Korzenev, A.; Kotzinian, A.M.; Kouznetsov, O.; Kowalik, K.; Kramer, M.; Kral, A.; Kroumchtein, Z.V.; Kuhn, R.; Kunne, F.; Kurek, K.; Lauser, L.; Le Goff, J.M.; Lednev, A.A.; Lehmann, A.; Levorato, S.; Lichtenstadt, J.; Liska, T.; Maggiora, A.; Maggiora, M.; Magnon, A.; Mallot, G.K.; Mann, A.; Marchand, C.; Marroncle, J.; Martin, A.; Marzec, J.; Massmann, F.; Matsuda, T.; Maximov, A.N.; Meyer, W.; Michigami, T.; Mikhailov, Yu.V.; Moinester, M.A.; Mutter, A.; Nagaytsev, A.; Nagel, T.; Nassalski, J.; Negrini, T.; Nerling, F.; Neubert, S.; Neyret, D.; Nikolaenko, V.I.; Nunes, A.S.; Olshevsky, A.G.; Ostrick, M.; Padee, A.; Panknin, R.; Panzieri, D.; Parsamyan, B.; Paul, S.; Pawlukiewicz-Kaminska, B.; Perevalova, E.; Pesaro, G.; Peshekhonov, D.V.; Piragino, G.; Platchkov, S.; Pochodzalla, J.; Polak, J.; Polyakov, V.A.; Pontecorvo, G.; Pretz, J.; Quintans, C.; Rajotte, J.F.; Ramos, S.; Rapatsky, V.; Reicherz, G.; Richter, A.; Robinet, F.; Rocco, E.; Rondio, E.; Ryabchikov, D.I.; Samoylenko, V.D.; Sandacz, A.; Santos, H.; Sapozhnikov, M.G.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schill, C.; Schmitt, L.; Schluter, T.; Schopferer, S.; Schroder, W.; Shevchenko, O.Yu.; Siebert, H.W.; Silva, L.; Sinha, L.; Sissakian, A.N.; Slunecka, M.; Smirnov, G.I.; Sosio, S.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Sulej, R.; Takekawa, S.; Tessaro, S.; Tessarotto, F.; Teufel, A.; Tkatchev, L.G.; Uhl, S.; Uman, I.; Virius, M.; Vlassov, N.V.; Vossen, A.; Weitzel, Q.; Windmolders, R.; Wislicki, W.; Wollny, H.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zhao, J.; Zhuravlev, N.; Zvyagin, A.

2010-01-01

The inclusive double-spin asymmetry, $A_{1}^{p}$, has been measured at COMPASS in deepinelastic polarised muon scattering off a large polarised NH3 target. The data, collected in the year 2007, cover the range Q2 > 1 (GeV/c)^2, 0.004 < x < 0.7 and improve the statistical precision of g_{1}^{p}(x) by a factor of two in the region x < 0.02. The new proton asymmetries are combined with those previously published for the deuteron to extract the non-singlet spin-dependent structure function g_1^NS(x,Q2). The isovector quark density, Delta_q_3(x,Q2), is evaluated from a NLO QCD fit of g_1^NS. The first moment of Delta_q3 is in good agreement with the value predicted by the Bjorken sum rule and corresponds to a ratio of the axial and vector coupling constants g_A/g_V = 1.28+-0.07(stat)+-0.10(syst).

Integrands for QCD rational terms and {N} = {4} SYM from massive CSW rules

Science.gov (United States)

Elvang, Henriette; Freedman, Daniel Z.; Kiermaier, Michael

2012-06-01

We use massive CSW rules to derive explicit compact expressions for integrands of rational terms in QCD with any number of external legs. Specifically, we present all- n integrands for the one-loop all-plus and one-minus gluon amplitudes in QCD. We extract the finite part of spurious external-bubble contributions systematically; this is crucial for the application of integrand-level CSW rules in theories without supersymmetry. Our approach yields integrands that are independent of the choice of CSW reference spinor even before integration. Furthermore, we present a recursive derivation of the recently proposed massive CSW-style vertex expansion for massive tree amplitudes and loop integrands on the Coulomb-branch of {N} = {4} SYM. The derivation requires a careful study of boundary terms in all-line shift recursion relations, and provides a rigorous (albeit indirect) proof of the recently proposed construction of massive amplitudes from soft-limits of massless on-shell amplitudes. We show that the massive vertex expansion manifestly preserves all holomorphic and half of the anti-holomorphic supercharges, diagram-by-diagram, even off-shell.

Introduction to non-perturbative quantum chromodynamics; Introduction a QCD non perturbatif

Energy Technology Data Exchange (ETDEWEB)

Pene, O. [Paris-11 Univ., 91 - Orsay (France). Lab. de Physique Theorique et Hautes Energies

1995-12-31

Quantum chromodynamics is considered to be the theory of strong interaction. The main peculiarity of this theory is that its asymptotic states (hadrons) are different from its elementary fields (quarks and gluons). This property plays a great part in any physical process involving small momentum-energy transfers. In such a range perturbative methods are no longer allowed. This work focuses on other tools such as QCD symmetry, the quark model, Green functions and the sum rules. To get hadron characteristics numerically, QCD on lattices is used but only in the case of simple process involving no more than one hadron in the initial and final states because of the complexity of the Green function. Some examples using a Monte-Carlo simulation are given. (A.C.) 39 refs.

Sum rules, asymptotic behaviour and (multi)baryon states in the Skyrme model

International Nuclear Information System (INIS)

Mignaco, J.A.; Wulck, S.

1990-01-01

We obtain sum roles that should be satisfied by the solutions of the Euler-Lagrange equation for the chiral angle in the Skyrme model in the hedgehog representation. The sum rules allow to determine the existence of solutions with integer baryon number for well determined values of a relevant dimensionless parameter Φ only. For all other values, there are no solutions with integer baryon number, in particular for the pure non-linear sigma model. (author)

Spectral sum rules and search for periodicities in DNA sequences

International Nuclear Information System (INIS)

Chechetkin, V.R.

2011-01-01

Periodic patterns play the important regulatory and structural roles in genomic DNA sequences. Commonly, the underlying periodicities should be understood in a broad statistical sense, since the corresponding periodic patterns have been strongly distorted by the random point mutations and insertions/deletions during molecular evolution. The latent periodicities in DNA sequences can be efficiently displayed by Fourier transform. The criteria of significance for observed periodicities are obtained via the comparison versus the counterpart characteristics of the reference random sequences. We show that the restrictions imposed on the significance criteria by the rigorous spectral sum rules can be rationally described with De Finetti distribution. This distribution provides the convenient intermediate asymptotic form between Rayleigh distribution and exact combinatoric theory. - Highlights: → We study the significance criteria for latent periodicities in DNA sequences. → The constraints imposed by sum rules can be described with De Finetti distribution. → It is intermediate between Rayleigh distribution and exact combinatoric theory. → Theory is applicable to the study of correlations between different periodicities. → The approach can be generalized to the arbitrary discrete Fourier transform.

Finite energy sum rules and instantons in the instanton liquid model

International Nuclear Information System (INIS)

Elias, V.; Fang Shi; Steele, T.G.

1998-01-01

We obtain the imaginary part of the direct single-instanton contribution to the pseudoscalar correlator, as defined by the appropriate dispersion relation, in order to derive an explicit integral representation for the instanton contribution to finite energy sum rules in the instanton liquid model. (author)

Duality between QCD perturbative series and power corrections

International Nuclear Information System (INIS)

Narison, S.; Zakharov, V.I.

2009-01-01

We elaborate on the relation between perturbative and power-like corrections to short-distance sensitive QCD observables. We confront theoretical expectations with explicit perturbative calculations existing in literature. As is expected, the quadratic correction is dual to a long perturbative series and one should use one of them but not both. However, this might be true only for very long perturbative series, with number of terms needed in most cases exceeding the number of terms available. What has not been foreseen, the quartic corrections might also be dual to the perturbative series. If confirmed, this would imply a crucial modification of the dogma. We confront this quadratic correction against existing phenomenology (QCD (spectral) sum rules scales, determinations of light quark masses and of α s from τ-decay). We find no contradiction and (to some extent) better agreement with the data and with recent lattice calculations.

Duality between QCD perturbative series and power corrections

Energy Technology Data Exchange (ETDEWEB)

Narison, S. [Laboratoire de Physique Theorique et Astroparticules, CNRS-IN2P3 and Universite de Montpellier II, Case 070, Place Eugene, 34095 Montpellier Cedex 05 (France)], E-mail: snarison@yahoo.fr; Zakharov, V.I. [Max-Planck-Institut fuer Physik, Foehringer Ring 6, 80805 Munich (Germany); Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, Moscow 117218 (Russian Federation)], E-mail: xxz@mppmu.mpg.de

2009-08-31

We elaborate on the relation between perturbative and power-like corrections to short-distance sensitive QCD observables. We confront theoretical expectations with explicit perturbative calculations existing in literature. As is expected, the quadratic correction is dual to a long perturbative series and one should use one of them but not both. However, this might be true only for very long perturbative series, with number of terms needed in most cases exceeding the number of terms available. What has not been foreseen, the quartic corrections might also be dual to the perturbative series. If confirmed, this would imply a crucial modification of the dogma. We confront this quadratic correction against existing phenomenology (QCD (spectral) sum rules scales, determinations of light quark masses and of {alpha}{sub s} from {tau}-decay). We find no contradiction and (to some extent) better agreement with the data and with recent lattice calculations.

Spin Sum Rules and Polarizabilities: Results from Jefferson Lab

International Nuclear Information System (INIS)

Jian-Ping Chen

2006-01-01

The nucleon spin structure has been an active, exciting and intriguing subject of interest for the last three decades. Recent experimental data on nucleon spin structure at low to intermediate momentum transfers provide new information in the confinement regime and the transition region from the confinement regime to the asymptotic freedom regime. New insight is gained by exploring moments of spin structure functions and their corresponding sum rules (i.e. the generalized Gerasimov-Drell-Hearn, Burkhardt-Cottingham and Bjorken). The Burkhardt-Cottingham sum rule is verified to good accuracy. The spin structure moments data are compared with Chiral Perturbation Theory calculations at low momentum transfers. It is found that chiral perturbation calculations agree reasonably well with the first moment of the spin structure function g 1 at momentum transfer of 0.05 to 0.1 GeV 2 but fail to reproduce the neutron data in the case of the generalized polarizability (delta) LT (the (delta) LT puzzle). New data have been taken on the neutron ( 3 He), the proton and the deuteron at very low Q 2 down to 0.02 GeV 2 . They will provide benchmark tests of Chiral dynamics in the kinematic region where the Chiral Perturbation theory is expected to work

Modified Adler sum rule and violation of charge symmetry

International Nuclear Information System (INIS)

Dominguez, C.A.; Moreno, H.; Zepeda, A.

The consequences of a once subtracted dispersion relation in the derivation of the Adler sum rule are investigated. It is shown that one can expect a breakdown of charge symmetry, of the isotriplet current hypothesis, and of scaling of the structure functions. These breakdowns are related to the possible presence of a non-zero subtraction function at asymptotic energies and arbitrary q 2 . Second class currents and PCAC relations are also discussed

SUM-RULES FOR MAGNETIC DICHROISM IN RARE-EARTH 4F-PHOTOEMISSION

NARCIS (Netherlands)

THOLE, BT; VANDERLAAN, G

1993-01-01

We present new sum rules for magnetic dichroism in spin polarized photoemission from partly filled shells which give the expectation values of the orbital and spin magnetic moments and their correlations in the ground state. We apply this to the 4f photoemission of rare earths, where the

I. Photon transition amplitudes predicted by the transformation between current and constituent quarks. II. Saturation of the Drell--Hearn--Gerasimov sum rule

International Nuclear Information System (INIS)

Karliner, I.

1975-01-01

The SU(6)-W group structure appears in both current algebra and in the spectroscopy of hadrons. Recently, a considerable progress has taken place in relating these two SU(6)-W structures. The consequences of the proposed correspondence, as it applies to real photon transitions, are investigated in this work. The general structure of such transitions is shown, and a set of resulting selection rules is presented for the multipole character of the photon amplitudes. Many specific amplitudes for both mesons and baryons are worked out and their signs and magnitudes are compared with available experimental data. The saturation of the Drell-Hearn-Gerasimov sum rule for the forward spin-flip amplitude of nucleon Compton scattering was investigated. The sum rule saturation was studied using recent analyses of single pion photoproduction in the region up to photon laboratory energies of 1.2 GeV. The original sum rule is decomposed into separate sum rules originating from different isospin compnents of the electromagnetic current. All three sum rules receive important nonresonant as well as resonant contributions. The isovector-isovector sum rule, whose contributions are known best, is found to be nearly saturated, lending support to the assumptions underlying the sum rules. The failure of the isovector-isoscalar sumrule to be saturated is then presumably to be blamed on inadequate data for inelastic contributions. (Diss. Abs,r. Int., B)

Large-Nc quantum chromodynamics and harmonic sums

Indian Academy of Sciences (India)

In the large- limit of QCD, two-point functions of local operators become harmonic sums. I review some properties which follow from this fact and which are relevant for phenomenological applications. This has led us to consider a class of analytic number theory functions as toy models of large- QCD which also is ...

A next-to-leading order QCD analysis of the spin structure function $g_1$

CERN Document Server

AUTHOR|(CDS)2067425; Arik, E; Badelek, B; Bardin, G; Baum, G; Berglund, P; Betev, L; Birsa, R; De Botton, N R; Bradamante, Franco; Bravar, A; Bressan, A; Bültmann, S; Burtin, E; Crabb, D; Cranshaw, J; Çuhadar-Dönszelmann, T; Dalla Torre, S; Van Dantzig, R; Derro, B R; Deshpande, A A; Dhawan, S K; Dulya, C M; Eichblatt, S; Fasching, D; Feinstein, F; Fernández, C; Forthmann, S; Frois, Bernard; Gallas, A; Garzón, J A; Gilly, H; Giorgi, M A; von Goeler, E; Görtz, S; Gracia, G; De Groot, N; Grosse-Perdekamp, M; Haft, K; Von Harrach, D; Hasegawa, T; Hautle, P; Hayashi, N; Heusch, C A; Horikawa, N; Hughes, V W; Igo, G; Ishimoto, S; Iwata, T; Kabuss, E M; Kageya, T; Karev, A G; Kessler, H J; Ketel, T; Kiryluk, J; Kiselev, Yu F; Krämer, Dietrich; Krivokhizhin, V G; Kröger, W; Kukhtin, V V; Kurek, K; Kyynäräinen, J; Lamanna, M; Landgraf, U; Le Goff, J M; Lehár, F; de Lesquen, A; Lichtenstadt, J; Litmaath, M; Magnon, A; Mallot, G K; Marie, F; Martin, A; Martino, J; Matsuda, T; Mayes, B W; McCarthy, J S; Medved, K S; Meyer, W T; Van Middelkoop, G; Miller, D; Miyachi, Y; Mori, K; Moromisato, J H; Nassalski, J P; Naumann, Lutz; Niinikoski, T O; Oberski, J; Ogawa, A; Ozben, C; Pereira, H; Perrot-Kunne, F; Peshekhonov, V D; Piegia, R; Pinsky, L; Platchkov, S K; Pló, M; Pose, D; Postma, H; Pretz, J; Puntaferro, R; Rädel, G; Rijllart, A; Reicherz, G; Roberts, J; Rodríguez, M; Rondio, Ewa; Sabo, I; Saborido, J; Sandacz, A; Savin, I A; Schiavon, R P; Schiller, A; Sichtermann, E P; Simeoni, F; Smirnov, G I; Staude, A; Steinmetz, A; Stiegler, U; Stuhrmann, H B; Szleper, M; Tessarotto, F; Thers, D; Tlaczala, W; Tripet, A; Ünel, G; Velasco, M; Vogt, J; Voss, Rüdiger; Whitten, C; Windmolders, R; Willumeit, R; Wislicki, W; Witzmann, A; Ylöstalo, J; Zanetti, A M; Zaremba, K; Zhao, J

1998-01-01

We present a next-to-leading order QCD analysis of the presently available data on the spin structure function $g_1$ including the final data from the Spin Muon Collaboration (SMC). We present resu lts for the first moments of the proton, deuteron and neutron structure functions, and determine singlet and non-singlet parton distributions in two factorization schemes. We also test the Bjor ken sum rule and find agreement with the theoretical prediction at the level of 10\\%.

Renormalization and applications of baryon distribution amplitudes QCD

International Nuclear Information System (INIS)

Rohrwild, Juergen Holger

2009-01-01

Higher-twist effects are relevant for precision calculations of hard exclusive reactions. Furthermore, they reveal fine details of the hadron structure. In this work we construct an operator basis for arbitrary twist respecting the conformal symmetry of QCD (which is realized on 1-loop level). Using this basis the 1-loop renormalization kernels of twist 4 are constructed for baryon operators. The full spectrum of anomalous dimensions and the multiplicatively renormalizable operators is obtained. As an application of these results the radiative N * (1535) decay is discussed. Employing light-cone sum rule, the transition form factors can be directly related to the N * distribution amplitudes. (orig.)

Renormalization and applications of baryon distribution amplitudes QCD

Energy Technology Data Exchange (ETDEWEB)

Rohrwild, Juergen Holger

2009-07-17

Higher-twist effects are relevant for precision calculations of hard exclusive reactions. Furthermore, they reveal fine details of the hadron structure. In this work we construct an operator basis for arbitrary twist respecting the conformal symmetry of QCD (which is realized on 1-loop level). Using this basis the 1-loop renormalization kernels of twist 4 are constructed for baryon operators. The full spectrum of anomalous dimensions and the multiplicatively renormalizable operators is obtained. As an application of these results the radiative N{sup *}(1535) decay is discussed. Employing light-cone sum rule, the transition form factors can be directly related to the N{sup *} distribution amplitudes. (orig.)

Dense QCD in a Finite Volume

International Nuclear Information System (INIS)

Yamamoto, Naoki; Kanazawa, Takuya

2009-01-01

We study the properties of QCD at high baryon density in a finite volume where color superconductivity occurs. We derive exact sum rules for complex eigenvalues of the Dirac operator at a finite chemical potential, and show that the Dirac spectrum is directly related to the color superconducting gap Δ. Also, we find a characteristic signature of color superconductivity: an X-shaped spectrum of partition function zeros in the complex quark mass plane near the origin, reflecting the Z(2) L xZ(2) R symmetry of the diquark pairing. Our results are universal in the domain Δ -1 π -1 where L is the linear size of the system and m π is the pion mass at high density.

Sum rules and other properties involving resonance projection operators. [for optical potential description of electron scattering from atoms and ions

Science.gov (United States)

Berk, A.; Temkin, A.

1985-01-01

A sum rule is derived for the auxiliary eigenvalues of an equation whose eigenspectrum pertains to projection operators which describe electron scattering from multielectron atoms and ions. The sum rule's right-hand side depends on an integral involving the target system eigenfunctions. The sum rule is checked for several approximations of the two-electron target. It is shown that target functions which have a unit eigenvalue in their auxiliary eigenspectrum do not give rise to well-defined projection operators except through a limiting process. For Hylleraas target approximations, the auxiliary equations are shown to contain an infinite spectrum. However, using a Rayleigh-Ritz variational principle, it is shown that a comparatively simple aproximation can exhaust the sum rule to better than five significant figures. The auxiliary Hylleraas equation is greatly simplified by conversion to a square root equation containing the same eigenfunction spectrum and from which the required eigenvalues are trivially recovered by squaring.

Non-leading contributions in QCD: Summing the perturbative series

International Nuclear Information System (INIS)

Trentadue, L.

1984-01-01

This paper presents the results of a systematic analysis of the leading and non-leading contributions in perturbative QCD and addresses the question of logarithmic contributions to all orders of the perturbative series

Analytic and algorithmic aspects of generalized harmonic sums and polylogarithms

International Nuclear Information System (INIS)

Ablinger, Jakob; Schneider, Carsten

2013-01-01

In recent three-loop calculations of massive Feynman integrals within Quantum Chromodynamics (QCD) and, e.g., in recent combinatorial problems the so-called generalized harmonic sums (in short S-sums) arise. They are characterized by rational (or real) numerator weights also different from ±1. In this article we explore the algorithmic and analytic properties of these sums systematically. We work out the Mellin and inverse Mellin transform which connects the sums under consideration with the associated Poincare iterated integrals, also called generalized harmonic polylogarithms. In this regard, we obtain explicit analytic continuations by means of asymptotic expansions of the S-sums which started to occur frequently in current QCD calculations. In addition, we derive algebraic and structural relations, like differentiation w.r.t. the external summation index and different multi-argument relations, for the compactification of S-sum expressions. Finally, we calculate algebraic relations for infinite S-sums, or equivalently for generalized harmonic polylogarithms evaluated at special values. The corresponding algorithms and relations are encoded in the computer algebra package HarmonicSums.

Analytic and algorithmic aspects of generalized harmonic sums and polylogarithms

Energy Technology Data Exchange (ETDEWEB)

Ablinger, Jakob; Schneider, Carsten [Johannes Kepler Univ., Linz (Austria). Research Inst. for Symbolic Computation; Bluemlein, Johannes [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)

2013-01-15

In recent three-loop calculations of massive Feynman integrals within Quantum Chromodynamics (QCD) and, e.g., in recent combinatorial problems the so-called generalized harmonic sums (in short S-sums) arise. They are characterized by rational (or real) numerator weights also different from {+-}1. In this article we explore the algorithmic and analytic properties of these sums systematically. We work out the Mellin and inverse Mellin transform which connects the sums under consideration with the associated Poincare iterated integrals, also called generalized harmonic polylogarithms. In this regard, we obtain explicit analytic continuations by means of asymptotic expansions of the S-sums which started to occur frequently in current QCD calculations. In addition, we derive algebraic and structural relations, like differentiation w.r.t. the external summation index and different multi-argument relations, for the compactification of S-sum expressions. Finally, we calculate algebraic relations for infinite S-sums, or equivalently for generalized harmonic polylogarithms evaluated at special values. The corresponding algorithms and relations are encoded in the computer algebra package HarmonicSums.

Analytic and algorithmic aspects of generalized harmonic sums and polylogarithms

Energy Technology Data Exchange (ETDEWEB)

Ablinger, Jakob; Schneider, Carsten [Research Institute for Symbolic Computation (RISC), Johannes Kepler University, Altenbergerstraße 69, A-4040, Linz (Austria); Blümlein, Johannes [Deutsches Elektronen–Synchrotron, DESY, Platanenallee 6, D-15738 Zeuthen (Germany)

2013-08-15

In recent three-loop calculations of massive Feynman integrals within Quantum Chromodynamics (QCD) and, e.g., in recent combinatorial problems the so-called generalized harmonic sums (in short S-sums) arise. They are characterized by rational (or real) numerator weights also different from ±1. In this article we explore the algorithmic and analytic properties of these sums systematically. We work out the Mellin and inverse Mellin transform which connects the sums under consideration with the associated Poincaré iterated integrals, also called generalized harmonic polylogarithms. In this regard, we obtain explicit analytic continuations by means of asymptotic expansions of the S-sums which started to occur frequently in current QCD calculations. In addition, we derive algebraic and structural relations, like differentiation with respect to the external summation index and different multi-argument relations, for the compactification of S-sum expressions. Finally, we calculate algebraic relations for infinite S-sums, or equivalently for generalized harmonic polylogarithms evaluated at special values. The corresponding algorithms and relations are encoded in the computer algebra package HarmonicSums.

Renormalization and applications of baryon distribution amplitudes in QCD

International Nuclear Information System (INIS)

Rohrwild, Juergen Holger

2009-01-01

Higher-twist effects are relevant for precision calculations of hard exclusive reactions. Furthermore, they reveal fine details of the hadron structure. In this work we construct an operator basis for arbitrary twist respecting the conformal symmetry of QCD (which is realized on 1-loop level). Using this basis the 1-loop renormalization kernels of twist 4 are constructed for baryon operators. The full spectrum of anomalous dimensions and the multiplicatively renormalizable operators is obtained. As an application of these results the radiative N * (1535) decay is discussed. Employing light-cone sum rule, the transition form factors can be directly related to the N* distribution amplitudes. (orig.)

Renormalization and applications of baryon distribution amplitudes in QCD

Energy Technology Data Exchange (ETDEWEB)

Rohrwild, Juergen Holger

2009-07-17

Higher-twist effects are relevant for precision calculations of hard exclusive reactions. Furthermore, they reveal fine details of the hadron structure. In this work we construct an operator basis for arbitrary twist respecting the conformal symmetry of QCD (which is realized on 1-loop level). Using this basis the 1-loop renormalization kernels of twist 4 are constructed for baryon operators. The full spectrum of anomalous dimensions and the multiplicatively renormalizable operators is obtained. As an application of these results the radiative N{sup *}(1535) decay is discussed. Employing light-cone sum rule, the transition form factors can be directly related to the N* distribution amplitudes. (orig.)

Renormalized sum rules for structure functions of heavy meson decays

International Nuclear Information System (INIS)

Grozin, A.G.; Korchemsky, G.P.

1996-01-01

We consider the properties of the structure functions of inclusive heavy meson decays B→X c and treat the c quark mass as a free parameter. We show that in two extreme cases of heavy and light c quarks the structure functions of heavy-heavy and heavy-light transitions are given by a Fourier transform of the matrix elements of Wilson lines containing a timelike and a lightlike segment, correspondingly. Using the renormalization properties of Wilson lines we find the dependence of the structure functions on the factorization scale, the structure function of the heavy-heavy transition is renormalized multiplicatively, while that of the heavy-light transition obeys the GLAP-type evolution equation. We propose a generalization of the sum rules for the moments of the structure functions (Bjorken, Voloshin, and the open-quote open-quote third close-quote close-quote sum rules) with a soft exponential factorization cutoff, which correctly incorporates both perturbative and nonperturbative effects. We analyze nonperturbative corrections by first considering infrared renormalon contributions to the Wilson lines. Uncertainties induced by the leading renormalon pole at u=1/2 are exactly canceled by a similar uncertainty in the heavy quark pole mass. The leading nonperturbative corrections associated with the next renormalon at u=1 are parametrized by the matrix element μ π 2 which is proportional to the heavy quark kinetic energy. copyright 1996 The American Physical Society

Sum rule approach to the study of statistical decay properties of nuclear giant resonances

International Nuclear Information System (INIS)

Adhikari, S.K.; Hussein, M.S.

1987-03-01

Corrections to the well-known statistical sum rule that relates the summed transmission coefficients on the one hand and 2πΓ C.N. .ρ C.N. On the other, in the context of the statistical decay properties of nuclear giant resonances, are discussed. These corrections arise both from pre-equilibrium processes as well as from the giant resonance itself. It is shown that the compound nucleus average width is reduced as a result of these corrections. (Author) [pt

QCD and Light-Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.

2010-10-27

The soft-wall AdS/QCD model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics. The model predicts a zero-mass pion for zero-mass quarks and a Regge spectrum of linear trajectories with the same slope in the leading orbital angular momentum L of hadrons and the radial quantum number N. Light-Front Holography maps the amplitudes which are functions of the fifth dimension variable z of anti-de Sitter space to a corresponding hadron theory quantized on the light front. The resulting Lorentz-invariant relativistic light-front wave equations are functions of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. The result is to a semi-classical frame-independent first approximation to the spectra and light-front wavefunctions of meson and baryon light-quark bound states, which in turn predict the behavior of the pion and nucleon form factors. The theory implements chiral symmetry in a novel way: the effects of chiral symmetry breaking increase as one goes toward large interquark separation, consistent with spectroscopic data, and the the hadron eigenstates generally have components with different orbital angular momentum; e.g., the proton eigenstate in AdS/QCD with massless quarks has L = 0 and L = 1 light-front Fock components with equal probability. The soft-wall model also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q) and its {beta}-function which agrees with the effective coupling {alpha}{sub g1} extracted from the Bjorken sum rule. The AdS/QCD model can be systematically improved by using its complete orthonormal solutions to diagonalize the full QCD light-front Hamiltonian or by applying the Lippmann-Schwinger method in order to systematically include the QCD interaction terms. A new perspective on quark and gluon condensates is also reviewed.

The Spin Structure Function $g_1^{\\rm p}$ of the Proton and a Test of the Bjorken Sum Rule

CERN Document Server

Adolph, C.; Alexeev, M.G.; Alexeev, G.D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Baum, G.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E.R.; Birsa, R.; Bisplinghoff, J.; Bodlak, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Buchele, M.; Burtin, E.; Capozza, L.; Chang, W.C.; Chiosso, M.; Choi, I.; Chung, S.U.; Cicuttin, A.; Crespo, M.L.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S.S.; Dasgupta, S.; Denisov, O.Yu.; Dhara, L.; Donskov, S.V.; Doshita, N.; Duic, V.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Ferrero, A.; Finger, M.; M. Finger jr; Fischer, H.; Franco, C.; von Hohenesche, N. du Fresne; Friedrich, J.M.; Frolov, V.; Fuchey, E.; Gautheron, F.; Gavrichtchouk, O.P.; Gerassimov, S.; Giordano, F.; Gnesi, I.; Gorzellik, M.; Grabmuller, S.; Grasso, A.; Grosse-Perdekamp, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; Hahne, D.; von Harrach, D.; Hashimoto, R.; Heinsius, F.H.; Herrmann, F.; Hinterberger, F.; Horikawa, N.; d'Hose, N.; Hsieh, C.Yu; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jary, V.; Jorg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G.V.; Khokhlov, Yu. A.; Kisselev, Yu.; Klein, F.; Klimaszewski, K.; Koivuniemi, J.H.; Kolosov, V.N.; Kondo, K.; Konigsmann, K.; Konorov, I.; Konstantinov, V.F.; Kotzinian, A.M.; Kouznetsov, O.; Kramer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z.V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R.P.; Lednev, A.A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Longo, R.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.K.; Marchand, C.; Martin, A.; Marzec, J.; Matousek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V.I.; Novy, J.; Nowak, W.D.; Nunes, A.S.; Olshevsky, A.G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.C.; Pereira, F.; Pesek, M.; Peshekhonov, D.V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.A.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N.S.; Ryabchikov, D.I.; Rychter, A.; Samoylenko, V.D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I.A.; Sbrizzai, G.; Schiavon, P.; Schmidt, K.; Schmieden, H.; Schonning, K.; Schopferer, S.; Selyunin, A.; Shevchenko, O.Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, A.; Stolarski, M.; Sulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Wolbeek, J. ter; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tosello, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Weisrock, T.; Wilfert, M.; Windmolders, R.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.

2016-02-10

New results for the double spin asymmetry $A_1^{\\rm p}$ and the proton longitudinal spin structure function $g_1^{\\rm p}$ are presented. They were obtained by the COMPASS collaboration using polarised 200 GeV muons scattered off a longitudinally polarised NH$_3$ target. The data were collected in 2011 and complement those recorded in 2007 at 160\\,GeV, in particular at lower values of $x$. They improve the statistical precision of $g_1^{\\rm p}(x)$ by about a factor of two in the region $x\\lesssim 0.02$. A next-to-leading order QCD fit to the $g_1$ world data is performed. It leads to a new determination of the quark spin contribution to the nucleon spin, $\\Delta \\Sigma$ ranging from 0.26 to 0.36, and to a re-evaluation of the first moment of $g_1^{\\rm p}$. The uncertainty of $\\Delta \\Sigma$ is mostly due to the large uncertainty in the present determinations of the gluon helicity distribution. A new evaluation of the Bjorken sum rule based on the COMPASS results for the non-singlet structure function $g_1^{\\rm...

Relativistic chiral SU(3) symmetry, large Nc sum rules and meson-baryon scattering

International Nuclear Information System (INIS)

Lutz, M.F.M.; Kolomeitsev, E.E.

2001-05-01

The relativistic chiral SU(3) Lagrangian is used to describe kaon-nucleon scattering imposing constraints from the pion-nucleon sector and the axial-vector coupling constants of the baryon octet states. We solve the covariant coupled-channel Bethe-Salpeter equation with the interaction kernel truncated at chiral order Q 3 where we include only those terms which are leading in the large N c limit of QCD. The baryon decuplet states are an important explicit ingredient in our scheme, because together with the baryon octet states they form the large N c baryon ground states of QCD. Part of our technical developments is a minimal chiral subtraction scheme within dimensional regularization, which leads to a manifest realization of the covariant chiral counting rules. All SU(3) symmetry-breaking effects are well controlled by the combined chiral and large N c expansion, but still found to play a crucial role in understanding the empirical data. We achieve an excellent description of the data set typically up to laboratory momenta of p lab ≅ 500 MeV. (orig.)

Perturbative corrections to B → D form factors in QCD

Science.gov (United States)

Wang, Yu-Ming; Wei, Yan-Bing; Shen, Yue-Long; Lü, Cai-Dian

2017-06-01

We compute perturbative QCD corrections to B → D form factors at leading power in Λ/ m b , at large hadronic recoil, from the light-cone sum rules (LCSR) with B-meson distribution amplitudes in HQET. QCD factorization for the vacuum-to- B-meson correlation function with an interpolating current for the D-meson is demonstrated explicitly at one loop with the power counting scheme {m}_c˜ O(√{Λ {m}_b}) . The jet functions encoding information of the hard-collinear dynamics in the above-mentioned correlation function are complicated by the appearance of an additional hard-collinear scale m c , compared to the counterparts entering the factorization formula of the vacuum-to- B-meson correction function for the construction of B → π from factors. Inspecting the next-to-leading-logarithmic sum rules for the form factors of B → Dℓν indicates that perturbative corrections to the hard-collinear functions are more profound than that for the hard functions, with the default theory inputs, in the physical kinematic region. We further compute the subleading power correction induced by the three-particle quark-gluon distribution amplitudes of the B-meson at tree level employing the background gluon field approach. The LCSR predictions for the semileptonic B → Dℓν form factors are then extrapolated to the entire kinematic region with the z-series parametrization. Phenomenological implications of our determinations for the form factors f BD +,0 ( q 2) are explored by investigating the (differential) branching fractions and the R( D) ratio of B → Dℓν and by determining the CKM matrix element |V cb | from the total decay rate of B → Dμν μ .

Isovector giant monopole resonances: A sum-rule approach

International Nuclear Information System (INIS)

Goeke, K.; Bonn Univ.; Castel, B.

1980-01-01

Several useful sum rules associated with isovector giant monopole resonances are calculated for doubly closed shell nuclei. The calculation is based on techniques known from constrained and adiabatic time-dependent Hartree-Fock theories and assume various Skyrme interactions. The results obtained form, together with the compiled literature, the basis for a quantitative description of the RPA strength distribution in terms of energy-weighted moments. These, together with strength distribution properties, are determined by a hierarchy of determinantal relations between moments. The isovector giant monopole resonance turns out to be a rather broad resonance centered at E = 46 Asup(-1/10) MeV with an extended width of more than 16 MeV. The consequences regarding isospin impurities in the nuclear ground state are discussed. (orig.)

Origin of the violation of the Gottfried sum rule

International Nuclear Information System (INIS)

Hwang, W.P.; Speth, J.

1992-01-01

Using generalized Sullivan processes to generate sea-quark distributions of a nucleon at Q 2 =4 GeV 2 , we find that the recent finding by the New Muon Collaboration on the violation of the Gottfried sum rule can be understood quantitatively, including the shape of F 2 p (x)-F 2 n (x) as a function of x. The agreement may be seen as a clear evidence toward the validity of a recent suggestion of Hwang, Speth, and Brown that the sea distributions of a hadron, at low and moderate Q 2 (at least up to a few GeV 2 ), may be attributed primarily to generalized Sullivan processes

QCD and resonance physics. The rho-ω mixing

International Nuclear Information System (INIS)

Shifman, M.A.; Vainshtein, A.I.; Zakharov, V.I.

1978-01-01

The QCD-based approach to the resonance physics proposed earlier is extended to cover the rho-ω mixing problem. A two-point function relevant to the problem with account of nonperturbative contributions is considered. The sum rules are derived and related phenomenology is introduced. The rho-ω interference is found to be due to the relatively strong isotopic symmetry breaking in the quark masses, and a solution with msub(u) = 0, msub(d) not equal to 0 seems to be ruled out. It is shown that virtual photon exchanges alone can not explain the observed value of the mixing parameter. The phenomenon gets a natural explanation if one assumes a large isotopic symmetry violation in the mechanical quark masses, (msub(d) - msub(u))/(msub(d) + msub(u)) approximately 0.3. This number is close to that resulting from the well-known pseudoscalar meson analysis. Unlike the latter, the result, however, does not assume an exact SU(3)sub(flavor) symmetry in vacuum-to-vacuum matrix elements

Non-Perturbative QCD Coupling and Beta Function from Light Front Holography

International Nuclear Information System (INIS)

Brodsky, Stanley J.

2010-01-01

The light-front holographic mapping of classical gravity in AdS space, modified by a positive-sign dilaton background, leads to a non-perturbative effective coupling α s AdS (Q 2 ). It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale ∼ 1 GeV. The resulting β-function appears to capture the essential characteristics of the full β-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on α s AdS (Q 2 ).

xF 3( x,Q 2) Structure Function and Gross-Llewellyn Smith Sum Rule with Nuclear Effect and Higher Twist Correction

International Nuclear Information System (INIS)

Nath, N.M.; Mukharjee, A.; Das, M.K.; Sarma, J.K.

2016-01-01

We present an analysis of the xF 3 (x,Q 2 ) structure function and Gross-Llewellyn Smith(GLS) sum rule taking into account the nuclear effects and higher twist correction. This analysis is based on the results presented in [N.M. Nath, et al, Indian J. Phys. 90 (2016) 117]. The corrections due to nuclear effects predicted in several earlier analysis are incorporated to our results of xF 3 (x,Q 2 ) structure function and GLS sum rule for free nucleon, corrected upto next-next-to-leading order (NNLO) perturbative order and calculate the nuclear structure function as well as sum rule for nuclei. In addition, by means of a simple model we have extracted the higher twist contributions to the non-singlet structure function xF 3 (x,Q 2 ) and GLS sum rule in NNLO perturbative orders and then incorporated them to our results. Our NNLO results along with nuclear effect and higher twist corrections are observed to be compatible with corresponding experimental data and other phenomenological analysis. (paper)

Dependence of Coulomb Sum Rule on the Short Range Correlation by Using Av18 Potential

Science.gov (United States)

Modarres, M.; Moeini, H.; Moshfegh, H. R.

The Coulomb sum rule (CSR) and structure factor are calculated for inelastic electron scattering from nuclear matter at zero and finite temperature in the nonrelativistic limit. The effect of short-range correlation (SRC) is presented by using lowest order constrained variational (LOCV) method and the Argonne Av18 and Δ-Reid soft-core potentials. The effects of different potentials as well as temperature are investigated. It is found that the nonrelativistic version of Bjorken scaling approximately sets in at the momentum transfer of about 1.1 to 1.2 GeV/c and the increase of temperature makes it to decrease. While different potentials do not significantly change CSR, the SRC improves the Coulomb sum rule and we get reasonably close results to both experimental data and others theoretical predictions.

Subtractions in the Adler sum rule and violation of charge symmetry

International Nuclear Information System (INIS)

Dominguez, C.A.; Moreno, H.; Zepeda, A.

1976-01-01

The consequences of a once-subtracted dispersion relation in the derivation of the Adler sum rule are investigated. It is shown that one can expect a breakdown of charge symmetry, of the isotriplet-current hypothesis, and of scaling of the structure functions. These breakdowns are related to the possible presence of a nonzero subtraction function at asymptotic energies and arbitrary q 2 . We also comment about second-class currents and PCAC (partial conservation of axial-vector current) relations

The ADS/QCD correspondence and exclusive processes

International Nuclear Information System (INIS)

Brodsky, Stanley J.; De Teramond, Guy F.; Deur, Alexandre

2011-01-01

The AdS/CFT correspondence between theories in AdS space and conformal field theories in physical space-time provides an analytic, semi-classical, color-confining model for strongly-coupled QCD. The soft-wall AdS/QCD model, modified by a positive-sign dilaton metric, leads to a remarkable one-parameter description of nonperturbative hadron dynamics at zero quark mass, including a zero-mass pion and meson and baryon Regge spectra of linear trajectories with the same slope in orbital angular momentum L and radial quantum number n. One also predicts the form of the non-perturbative effective coupling alpha AdS/s (Q) and its Beta-function which agrees with the effective coupling alphag1 extracted from the Bjorken sum rule. Light-front holography, which connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable zeta, allows one to compute the analytic form of the frame-independent light-front wave functions, the fundamental entities which encode hadron properties as well as decay constants, form factors, deeply-virtual Compton scattering, exclusive heavy hadron decays, and other exclusive scattering amplitudes. One thus obtains a relativistic description of hadrons in QCD at the amplitude level with dimensional counting for exclusive reactions at high momentum transfer. As specific examples, we discuss the behavior of the pion and nucleon form factors in the space-like and time-like regions. We also review the phenomenology of exclusive processes including some anomalous empirical results.

The DHG sum rule measured with medium energy photons

International Nuclear Information System (INIS)

Hicks, K.; Ardashev, K.; Babusci, D.

1997-01-01

The structure of the nucleon has many important features that are yet to be uncovered. Of current interest is the nucleon spin-structure which can be measured by doing double-polarization experiments with photon beams of medium energies (0.1 to 2 GeV). One such experiment uses dispersion relations, applied to the Compton scattering amplitude, to relate measurement of the total reaction cross section integrated over the incident photon energy to the nucleon anomalous magnetic moment. At present, no single facility spans the entire range of photon energies necessary to test this sum rule. The Laser-Electron Gamma Source (LEGS) facility will measure the double-polarization observables at photon energies between 0.15--0.47 MeV. Either the SPring8 facility, the GRAAL facility (France), or Jefferson Laboratory could make similar measurements at higher photon energies. A high-precision measurement of the spin-polarizability and the Drell-Hearn-Gerasimov sum rule is now possible with the advent of high-polarization solid HD targets at medium energy polarized photon facilities such as LEGS, GRAAL and SPring8. Other facilities with lower polarization in either the photon beam or target (or both) are also pursuing these measurements because of the high priority associated with this physics. The Spin-asymmetry (SASY) detector that will be used at LEGS has been briefly outlined in this paper. The detector efficiencies have been explored with simulations studies using the GEANT software, with the result that both charged and uncharged pions can be detected with a reasonable efficiency (> 30%) over a large solid angle. Tracking with a TPC, which will be built at LEGS over the next few years, will improve the capabilities of these measurements

The Fubini-Furlan-Rosetti sum rule and related aspects in light of covariant baryon chiral perturbation theory

International Nuclear Information System (INIS)

Bernard, V.; Kubis, B.; Meissner, U.G.

2005-01-01

We analyze the Fubini-Furlan-Rosetti sum rule in the framework of covariant baryon chiral perturbation theory to leading one-loop accuracy and including next-to-leading-order polynomial contributions. We discuss the relation between the subtraction constants in the invariant amplitudes and certain low-energy constants employed in earlier chiral perturbation theory studies of threshold neutral pion photoproduction off nucleons. In particular, we consider the corrections to the sum rule due to the finite pion mass and show that below the threshold they agree well with determinations based on fixed-t dispersion relations. We also discuss the energy dependence of the electric dipole amplitude E 0+ . (orig.)

The Fubini-Furlan-Rosetti sum rule and related aspects in light of covariant baryon chiral perturbation theory

Energy Technology Data Exchange (ETDEWEB)

Bernard, V. [Universite Louis Pasteur, Laboratoire de Physique Theorique, Strasbourg Cedex 2 (France); Kubis, B. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Bonn (Germany); Meissner, U.G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik (Theorie), Bonn (Germany); Forschungszentrum Juelich, Institut fuer Kernphysik (Theorie), Juelich (Germany)

2005-09-01

We analyze the Fubini-Furlan-Rosetti sum rule in the framework of covariant baryon chiral perturbation theory to leading one-loop accuracy and including next-to-leading-order polynomial contributions. We discuss the relation between the subtraction constants in the invariant amplitudes and certain low-energy constants employed in earlier chiral perturbation theory studies of threshold neutral pion photoproduction off nucleons. In particular, we consider the corrections to the sum rule due to the finite pion mass and show that below the threshold they agree well with determinations based on fixed-t dispersion relations. We also discuss the energy dependence of the electric dipole amplitude E{sub 0+}. (orig.)

Frustrated Kinetic Energy, the Optical Sum Rule, and the Mechanism of Superconductivity

International Nuclear Information System (INIS)

Chakravarty, S.; Kee, H.; Abrahams, E.

1999-01-01

The basis of the interlayer tunneling theory of high-temperature superconductivity is that the electronic kinetic energy in a direction perpendicular to the copper-oxygen planes is a substantial fraction of the condensation energy. This issue is critically examined, and it is argued from a rigorous conductivity sum rule that the consequences of this theory are consistent with recent optical and penetration depth measurements. copyright 1999 The American Physical Society

Analytic continuation in perturbative QCD

International Nuclear Information System (INIS)

Caprini, Irinel

2002-01-01

We discuss some attempts to improve standard perturbative expansion in QCD by using the analytic continuation in the momentum and the Borel complex planes. We first analyse the momentum-plane analyticity properties of the Borel-summed Green functions in perturbative QCD and the connection between the Landau singularities and the infrared renormalons. By using the analytic continuation in the Borel complex plane, we propose a new perturbative series replacing the standard expansion in powers of the normalized coupling constant a. The new expansion functions have branch point and essential singularities at the origin of the complex a-plane and divergent Taylor expansions in powers of a. On the other hand the modified expansion of the QCD correlators is convergent under rather conservative conditions. (author)

Structural relations between nested harmonic sums

International Nuclear Information System (INIS)

Bluemlein, J.

2008-07-01

We describe the structural relations between nested harmonic sums emerging in the description of physical single scale quantities up to the 3-loop level in renormalizable gauge field theories. These are weight w=6 harmonic sums. We identify universal basic functions which allow to describe a large class of physical quantities and derive their complex analysis. For the 3-loop QCD Wilson coefficients 35 basic functions are required, whereas a subset of 15 describes the 3-loop anomalous dimensions. (orig.)

Structural relations between nested harmonic sums

Energy Technology Data Exchange (ETDEWEB)

Bluemlein, J.

2008-07-15

We describe the structural relations between nested harmonic sums emerging in the description of physical single scale quantities up to the 3-loop level in renormalizable gauge field theories. These are weight w=6 harmonic sums. We identify universal basic functions which allow to describe a large class of physical quantities and derive their complex analysis. For the 3-loop QCD Wilson coefficients 35 basic functions are required, whereas a subset of 15 describes the 3-loop anomalous dimensions. (orig.)

Structure of Nonlocal quark vacuum condensate in non-perturbative QCD vacuum

International Nuclear Information System (INIS)

Xiang Qianfei; Ma Weixing; Zhou Lijuan; Jiang Weizhou

2014-01-01

Based on the Dyson-Schwinger Equations (DSEs) with the rainbow truncation, and Operator Product Expansion, the structure of nonlocal quark vacuum condensate in QCD, described by quark self-energy functions A_f and B_f given usually by the solutions of the DSEs of quark propagator, is predicted numerically. We also calculate the local quark vacuum condensate, quark-gluon mixed local vacuum condensate, and quark virtuality. The self-energy functions A_f and B_f are given by the parameterized quark propagator functions σ_v"f (p"2) and σ_s"f (p"2) of Roberts and Williams, instead of the numerical solutions of the DSEs. Our calculated results are in reasonable agreement with those of QCD sum rules, Lattice QCD calculations, and instanton model predictions, although the resulting local quark vacuum condensate for light quarks, u, d, s, are a little bit larger than those of the above theoretical predictions. We think the differences are caused by model dependence. The larger of strange quark vacuum condensate than u, d quark is due to the s quark mass which is more larger than u, d quark masses. Of course, the Roberts-Williams parameterized quark propagator is an empirical formulism, which approximately describes quark propagation. (authors)

AdS/QCD, Light-Front Holography, and Sublimated Gluons

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC; de Teramond, Guy F.; /Costa Rica U.

2012-02-16

The gauge/gravity duality leads to a simple analytical and phenomenologically compelling nonperturbative approximation to the full light-front QCD Hamiltonian - 'Light-Front Holography', which provides a Lorentz-invariant first-approximation to QCD, and successfully describes the spectroscopy of light-quark meson and baryons, their elastic and transition form factors, and other hadronic properties. The bound-state Schroedinger and Dirac equations of the soft-wall AdS/QCD model predict linear Regge trajectories which have the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. Light-front holography connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable {zeta} in 3+1 space at fixed light-front time. A key feature is the determination of the frame-independent light-front wavefunctions of hadrons - the relativistic analogs of the Schroedinger wavefunctions of atomic physics which allow one to compute form factors, transversity distributions, spin properties of the valence quarks, jet hadronization, and other hadronic observables. One thus obtains a one-parameter color-confining model for hadron physics at the amplitude level. AdS/QCD also predicts the form of the non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q) and its {beta}-function with an infrared fixed point which agrees with the effective coupling a{sub g1} (Q{sup 2}) extracted from measurements of the Bjorken sum rule below Q{sup 2} < 1 GeV{sup 2}. This is consistent with a flux-tube interpretation of QCD where soft gluons with virtualities Q{sup 2} < 1 GeV{sup 2} are sublimated into a color-confining potential for quarks. We discuss a number of phenomenological hadronic properties which support this picture.

The AdS/QCD Correspondence and Exclusive Processes

International Nuclear Information System (INIS)

Brodsky, Stanley

2010-01-01

The AdS/CFT correspondence between theories in AdS space and conformal field theories in physical space-time provides an analytic, semi-classical, color-confining model for strongly-coupled QCD. The soft-wall AdS/QCD model modified by a positive-sign dilaton metric leads to a remarkable one-parameter description of nonperturbative hadron dynamics at zero quark mass, including a zero-mass pion and a Regge spectrum of linear trajectories with the same slope in orbital angular momentum L and radial quantum number n for both mesons and baryons. One also predicts the form of the non-perturbative effective coupling α s AdS (q) and its β-function which agrees with the effective coupling α ga extracted from the Bjorken sum rule. Light-front holography, which connects the fifth-dimensional coordinate of AdS space z to an invariant impact separation variable ζ, allows one to compute the analytic form of the frame-independent light-front wavefunctions, the fundamental entities which encode hadron properties as well as decay constants, form factors, deeply virtual Compton scattering, exclusive heavy hadron decays and other exclusive scattering amplitudes. One thus obtains a relativistic description of hadrons in QCD at the amplitude level with dimensional counting for hard exclusive reactions at high momentum transfer. As specific examples we discuss the behavior of the pion and nucleon form factors in the space-like and time-like regions. We also review the phenomenology of exclusive processes including some anomalous empirical results.

Sum rules and constraints on passive systems

International Nuclear Information System (INIS)

Bernland, A; Gustafsson, M; Luger, A

2011-01-01

A passive system is one that cannot produce energy, a property that naturally poses constraints on the system. A system in convolution form is fully described by its transfer function, and the class of Herglotz functions, holomorphic functions mapping the open upper half-plane to the closed upper half-plane, is closely related to the transfer functions of passive systems. Following a well-known representation theorem, Herglotz functions can be represented by means of positive measures on the real line. This fact is exploited in this paper in order to rigorously prove a set of integral identities for Herglotz functions that relate weighted integrals of the function to its asymptotic expansions at the origin and infinity. The integral identities are the core of a general approach introduced here to derive sum rules and physical limitations on various passive physical systems. Although similar approaches have previously been applied to a wide range of specific applications, this paper is the first to deliver a general procedure together with the necessary proofs. This procedure is described thoroughly and exemplified with examples from electromagnetic theory.

Conformal Aspects of QCD

Energy Technology Data Exchange (ETDEWEB)

Brodsky, S

2003-11-19

Theoretical and phenomenological evidence is now accumulating that the QCD coupling becomes constant at small virtuality; i.e., {alpha}{sub s}(Q{sup 2}) develops an infrared fixed point in contradiction to the usual assumption of singular growth in the infrared. For example, the hadronic decays of the {tau} lepton can be used to determine the effective charge {alpha}{sub {tau}}(m{sub {tau}{prime}}{sup 2}) for a hypothetical {tau}-lepton with mass in the range 0 < m{sub {tau}{prime}} < m{sub {tau}}. The {tau} decay data at low mass scales indicates that the effective charge freezes at a value of s = m{sub {tau}{prime}}{sup 2} of order 1 GeV{sup 2} with a magnitude {alpha}{sub {tau}} {approx} 0.9 {+-} 0.1. The near-constant behavior of effective couplings suggests that QCD can be approximated as a conformal theory even at relatively small momentum transfer and why there are no significant running coupling corrections to quark counting rules for exclusive processes. The AdS/CFT correspondence of large N{sub c} supergravity theory in higher-dimensional anti-de Sitter space with supersymmetric QCD in 4-dimensional space-time also has interesting implications for hadron phenomenology in the conformal limit, including an all-orders demonstration of counting rules for exclusive processes and light-front wavefunctions. The utility of light-front quantization and light-front Fock wavefunctions for analyzing nonperturbative QCD and representing the dynamics of QCD bound states is also discussed.

Resummation of perturbative QCD by pade approximants

International Nuclear Information System (INIS)

Gardi, E.

1997-01-01

In this lecture I present some of the new developments concerning the use of Pade Approximants (PA's) for resuming perturbative series in QCD. It is shown that PA's tend to reduce the renormalization scale and scheme dependence as compared to truncated series. In particular it is proven that in the limit where the β function is dominated by the 1-loop contribution, there is an exact symmetry that guarantees invariance of diagonal PA's under changing the renormalization scale. In addition it is shown that in the large β 0 approximation diagonal PA's can be interpreted as a systematic method for approximating the flow of momentum in Feynman diagrams. This corresponds to a new multiple scale generalization of the Brodsky-Lepage-Mackenzie (BLM) method to higher orders. I illustrate the method with the Bjorken sum rule and the vacuum polarization function. (author)

Sum rules and systematics for baryon magnetic moments

International Nuclear Information System (INIS)

Lipkin, H.J.

1983-11-01

The new experimental values of hyperon magnetic moments are compared with sum rules predicted from general quark models. Three difficulties encountered are not easily explained by simple models. The isovector contributions of nonstrange quarks to hyperon moments are smaller than the corresponding contribution to nucleon moments, indicating either appreciable configuration mixing in hyperon wave functions and absent in nucleons or an additional isovector contribution beyond that of valence quarks; e.g. from a pion cloud. The large magnitude of the THETA - moment may indicate that the strange quark contribution to the THETA moments is considerably larger than the value μ(Λ) predicted by simple models which have otherwise been very successful. The set of controversial values from different experiments of the Σ - moment include a value very close to -(1/2)μ(Σ + ) which would indicate that strange quarks do not contribute at all to the Σ moments. (author)

Sum rules and systematics for baryon magnetic moments

International Nuclear Information System (INIS)

Lipkin, H.J.

1984-01-01

The new experimental values of hyperon magnetic moments are compared with sum rules predicted from general quark models. Three difficulties encountered are not easily explained by simple models. The isovector contributions of nonstrange quarks to hyperon moments are smaller than the corresponding contribution to nucleon moments, indicating either appreciable configuration mixing in hyperon wave functions and absent in nucleons or an additional isovector contribution beyond that of valence quarks, e.g. from a pion cloud. The large magnitude of the Ψ - moment may indicate that the strange quark contribution to the Ψ moments is considerably larger than the value μ(Λ) predicted by simple models which have otherwise been very successful. The set of controversial values from different experiments of the Σ - moment include a value very close to -1/2μ(Σ + ) which would indicate that strange quarks do not contribute at all to the Σ moments. (orig.)

Composite Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-03-07

In this chapter, we extend the previous results of Chap. 2 to the more general case of composite finite sums. We describe what composite finite sums are and how their analysis can be reduced to the analysis of simple finite sums using the chain rule. We apply these techniques, next, on numerical integration and on some identities of Ramanujan.

Composite Finite Sums

KAUST Repository

Alabdulmohsin, Ibrahim M.

2018-01-01

In this chapter, we extend the previous results of Chap. 2 to the more general case of composite finite sums. We describe what composite finite sums are and how their analysis can be reduced to the analysis of simple finite sums using the chain rule. We apply these techniques, next, on numerical integration and on some identities of Ramanujan.

Non-Perturbative QCD Coupling and Beta Function from Light Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC /Southern Denmark U., CP3-Origins; de Teramond, Guy F.; /Costa Rica U.; Deur, Alexandre; /Jefferson Lab

2010-05-26

The light-front holographic mapping of classical gravity in AdS space, modified by a positive-sign dilaton background, leads to a non-perturbative effective coupling {alpha}{sub s}{sup AdS} (Q{sup 2}). It agrees with hadron physics data extracted from different observables, such as the effective charge defined by the Bjorken sum rule, as well as with the predictions of models with built-in confinement and lattice simulations. It also displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD. Commensurate scale relations relate observables to each other without scheme or scale ambiguity. In this paper we extrapolate these relations to the nonperturbative domain, thus extending the range of predictions based on {alpha}{sub s}{sup AdS} (Q{sup 2}).

Measurement of the Neutron (³He) Spin Structure at Low Q² and the Extended Gerasimov-Drell-Hearn Sum Rule

Energy Technology Data Exchange (ETDEWEB)

Kominis, Ioannis [Princeton Univ., NJ (United States)

2001-01-01

This thesis presents the results of E-94010, an experiment at Thomas Jefferson National Accelerator Facility (TJNAF) designed to study the spin structure of the neutron at low momentum transfer, and to test the “extended” Gerasimov-Drell-Hearn (GDH) sum rule. The first experiment of its kind, it was performed in experimental Hall-A of TJNAF using a new polarized ³He facility. It has recently been shown that the GDH sum rule and the Bjorken sum rule are both special examples of a more general sum rule that applies to polarized electron scattering off nucleons. This generalized sum rule, due to Ji and Osborne, reduces to the GDH sum rule at Q² = 0 and to the Bjorken sum rule at Q² >> 1 GeV². By studying the Q² evolution of the extended GDH sum, one learns about the transition from quark-like behavior to hadronic-like behavior. We measured inclusive polarized cross sections by scattering high energy polarized electrons off the new TJNAF polarized ³He target with both longitudinal and transverse target orientations. The high density ³He target, based on optical pumping and spin exchange, was used as an effective neutron target. The target maintained a polarization of about 35% at beam currents as high as 151tA. We describe the precision ³He polarimetry leading to a systematic uncertainty of the target polarization of 4% (relative). A strained GaAs photocathode was utilized in the polarized electron gun, which provided an electron beam with a polarization of about 70%, known to 3% (relative). By using six different beam energies (between 0.86 and 5.06 GeV) and a fixed scattering angle of 15.5°, a wide kinematic coverage was achieved, with 0.02 GeV²< Q² <1 GcV² and 0.5 GeV< W < 2.5 GeV for the squared momentum transfer and invariant mass, respectively. From the measured cross sections we extract the ³He spin structure functions g$3 He

Radiative ΩQ∗→ΩQγ and ΞQ∗→ΞQ′γ transitions in light cone QCD

International Nuclear Information System (INIS)

Aliev, T. M.; Azizi, K.; Sundu, H.

2015-01-01

We calculate the magnetic dipole and electric quadrupole moments associated with the radiative Ω Q ∗ →Ω Q γ and Ξ Q ∗ →Ξ Q ′ γ transitions with Q=b or c in the framework of light cone QCD sum rules. It is found that the corresponding quadrupole moments are negligibly small, while the magnetic dipole moments are considerably large. A comparison of the results of the considered multipole moments as well as corresponding decay widths with the predictions of the vector dominance model is performed

Renormalization group analysis of B →π form factors with B -meson light-cone sum rules

Science.gov (United States)

Shen, Yue-Long; Wei, Yan-Bing; Lü, Cai-Dian

2018-03-01

Within the framework of the B -meson light-cone sum rules, we review the calculation of radiative corrections to the three B →π transition form factors at leading power in Λ /mb. To resum large logarithmic terms, we perform the complete renormalization group evolution of the correlation function. We employ the integral transformation which diagonalizes evolution equations of the jet function and the B -meson light-cone distribution amplitude to solve these evolution equations and obtain renormalization group improved sum rules for the B →π form factors. Results of the form factors are extrapolated to the whole physical q2 region and are compared with that of other approaches. The effect of B -meson three-particle light-cone distribution amplitudes, which will contribute to the form factors at next-to-leading power in Λ /mb at tree level, is not considered in this paper.

Academic Training Lectures - QCD for Postgraduates

CERN Multimedia

Maureen Prola-Tessaur

2010-01-01

by Giulia Zanderighi (University of Oxford) Monday 12 to Friday 16 April 2010 From 11:00 to 12:00 - Main Auditorium, Bldg. 500-1-001 Monday 12 - Modern QCD - Lecture 1 Starting from the QCD Lagrangian we will revisit some basic QCD concepts and derive fundamental properties like gauge invariance and isospin symmetry and will discuss the Feynman rules of the theory. We will then focus on the gauge group of QCD and derive the Casimirs CF and CA and some useful color identities. Tuesday 13 - Modern QCD - Lecture 2 We will start discussing the matter content of the theory and revisit the experimental measurements that led to the discovery of quarks. We will then consider a classic QCD observable, the R-ratio, and use it to illustrate the appearance of UV divergences and the need to renormalize the coupling constant of QCD. We will then discuss asymptotic freedom and confinement. Finally, we will examine a case where soft and collinear infrared divergences appear, will discuss the soft approximation in QCD ...

Sum rule measurements of the spin-dependent compton amplitude (nucleon spin structure at Q2 = 0)

International Nuclear Information System (INIS)

Babusci, D.; Giordano, G.; Baghaei, H.; Cichocki, A.; Blecher, M.; Breuer, M.; Commeaux, C.; Didelez, J.P.; Caracappa, A.; Fan, Q.

1995-01-01

Energy weighted integrals of the difference in helicity-dependent photo-production cross sections (σ 1/2 - σ 3/2 ) provide information on the nucleon's Spin-dependent Polarizability (γ), and on the spin-dependent part of the asymptotic forward Compton amplitude through the Drell-Hearn-Gerasimov (DHG) sum rule. (The latter forms the Q 2 =0 limit of recent spin-asymmetry experiments in deep-inelastic lepton-scattering.) There are no direct measurements of σ 1/2 or σ 3/2 , for either the proton or the neutron. Estimates from current π-photo-production multipole analyses, particularly for the proton-neutron difference, are in good agreement with relativistic-l-loop Chiral calculations (χPT) for γ but predict large deviations from the DHG sum rule. Either (a) both the 2-loop corrections to the Spin-Polarizability are large and the existing multipoles are wrong, or (b) modifications to the Drell-Hearn-Gerasimov sum rule are required to fully describe the isospin structure of the nucleon. The helicity-dependent photo-reaction amplitudes, for both the proton and the neutron, will be measured at LEGS from pion-threshold to 470 MeV. In these double-polarization experiments, circularly polarized photons from LEGS will be used with SPHICE, a new frozen-spin target consisting of rvec H · rvec D in the solid phase. Reaction channels will be identified in SASY, a large detector array covering about 80% of 4π. A high degree of symmetry in both target and detector will be used to minimize systematic uncertainties

Scheme-Independent Predictions in QCD: Commensurate Scale Relations and Physical Renormalization Schemes

International Nuclear Information System (INIS)

Brodsky, Stanley J.

1998-01-01

Commensurate scale relations are perturbative QCD predictions which relate observable to observable at fixed relative scale, such as the ''generalized Crewther relation'', which connects the Bjorken and Gross-Llewellyn Smith deep inelastic scattering sum rules to measurements of the e + e - annihilation cross section. All non-conformal effects are absorbed by fixing the ratio of the respective momentum transfer and energy scales. In the case of fixed-point theories, commensurate scale relations relate both the ratio of couplings and the ratio of scales as the fixed point is approached. The relations between the observables are independent of the choice of intermediate renormalization scheme or other theoretical conventions. Commensurate scale relations also provide an extension of the standard minimal subtraction scheme, which is analytic in the quark masses, has non-ambiguous scale-setting properties, and inherits the physical properties of the effective charge α V (Q 2 ) defined from the heavy quark potential. The application of the analytic scheme to the calculation of quark-mass-dependent QCD corrections to the Z width is also reviewed

On the conductance sum rule for the hierarchical edge states of the fractional quantum hall effect

International Nuclear Information System (INIS)

Ma Zhongshui; Chen Yixin; Su Zhaobin.

1993-09-01

The conductance sum rule for the hierarchical edge channel currents of a Fractional Quantum Hall Effect state is derived analytically within the Haldane-Halperin hierarchy scheme. We provide also an intuitive interpretation for the hierarchical drift velocities of the edge excitations. (author). 12 refs

Spectral sum rules and magneto-roton as emergent graviton in fractional quantum Hall effect

Energy Technology Data Exchange (ETDEWEB)

Golkar, Siavash; Nguyen, Dung X.; Son, Dam T. [Enrico Fermi Institute, James Franck Institute and Department of Physics,University of Chicago, Chicago, Illinois 60637 (United States)

2016-01-05

We consider gapped fractional quantum Hall states on the lowest Landau level when the Coulomb energy is much smaller than the cyclotron energy. We introduce two spectral densities, ρ{sub T}(ω) and ρ̄{sub T}(ω), which are proportional to the probabilities of absorption of circularly polarized gravitons by the quantum Hall system. We prove three sum rules relating these spectral densities with the shift S, the q{sup 4} coefficient of the static structure factor S{sub 4}, and the high-frequency shear modulus of the ground state μ{sub ∞}, which is precisely defined. We confirm an inequality, first suggested by Haldane, that S{sub 4} is bounded from below by |S−1|/8. The Laughlin wavefunction saturates this bound, which we argue to imply that systems with ground state wavefunctions close to Laughlin’s absorb gravitons of predominantly one circular polarization. We consider a nonlinear model where the sum rules are saturated by a single magneto-roton mode. In this model, the magneto-roton arises from the mixing between oscillations of an internal metric and the hydrodynamic motion. Implications for experiments are briefly discussed.

Quasielastic 3Hp and 3Hep scattering at intermediate energies and Glauber sum rules

International Nuclear Information System (INIS)

Blinov, A.V.; Vanyushin, I.A.; Grechko, V.E.

1984-01-01

Differential cross sections and average energy losses of fast protons in reactions p +3 H→psub(F)+X and p+ 3 He → psub(F)+X are studied making use of the ITEP liquid hydrogen bubble chamber of 80-cm diameter exposed to 2.5-GeV/c tritium nuclei (the kinetic energy of the incident protons in the nucleus rest frame Tsub(p)=0.318 GeV) and to 5-GeV/c 3 He nuclei (Tsub(p)=0.978 GeV). The experimental results are compared to predictions based on the sum rules for differential cross sections and average energy losses in the Glauber-Sitenko multiple scattering theory using the completeness condition for the wave functions of the nuclear excited states and the locality of the nuclear potential. The theory and the data are in good agreement at momentum of 2.5 GeV/c. Inconsistence between the Glauber sum rule predictions and the 5 GeV/c data is attributed to the Δ-isobar production in the intermediate state. It is found that possible six-quark bag admixture in the 3 H and 3 He nuclei does not exceed 5%

A probabilistic approach of sum rules for heat polynomials

International Nuclear Information System (INIS)

Vignat, C; Lévêque, O

2012-01-01

In this paper, we show that the sum rules for generalized Hermite polynomials derived by Daboul and Mizrahi (2005 J. Phys. A: Math. Gen. http://dx.doi.org/10.1088/0305-4470/38/2/010) and by Graczyk and Nowak (2004 C. R. Acad. Sci., Ser. 1 338 849) can be interpreted and easily recovered using a probabilistic moment representation of these polynomials. The covariance property of the raising operator of the harmonic oscillator, which is at the origin of the identities proved in Daboul and Mizrahi and the dimension reduction effect expressed in the main result of Graczyk and Nowak are both interpreted in terms of the rotational invariance of the Gaussian distributions. As an application of these results, we uncover a probabilistic moment interpretation of two classical integrals of the Wigner function that involve the associated Laguerre polynomials. (paper)

Impact of Duality Violations on Spectral Sum Rule analyses

International Nuclear Information System (INIS)

Cata, Oscar

2007-01-01

Recent sum rule analyses on the two-point correlator have led to significant discrepancies in the values found for the OPE condensates, most dramatically in the dimension eight condensate and to a lesser extent in the dimension six one [R. Barate et al., ALEPH Collaboration, Eur. Phys. J. C 4 (1998) 409; K. Ackerstaff et al., OPAL Collaboration, Eur. Phys. J. C 7 (1999) 571, (arXiv:hep-ex/9808019); S. Peris, B. Phily and E. de Rafael, Phys. Rev. Lett. 86 (2001) 14, (arXiv:hep-ph/0007338); S. Friot, D. Greynat and E. de Rafael, JHEP 0410 (2004) 043, (arXiv:hep-ph/0408281); M. Davier, L. Girlanda, A. Hocker and J. Stern, Phys. Rev. D 58 (1998) 096014, (arXiv:hep-ph/9802447); B.L. Ioffe and K.N. Zyablyuk, Nucl. Phys. A 687 (2001) 437, (arXiv:hep-ph/0010089). K.N. Zyablyuk, Eur. Phys. J. C 38 (2004) 215, (arXiv:hep-ph/0404230); J. Bijnens, E. Gamiz and J. Prades, JHEP 0110 (2001) 009, (arXiv:hep-ph/0108240); C.A. Dominguez and K. Schilcher, Phys. Lett. B 581 (2004) 193, (arXiv:hep-ph/0309285); J. Rojo and J. I. Latorre, JHEP 0401 (2004) 055, (arXiv:hep-ph/0401047); V. Cirigliano, E. Golowich and K. Maltman, Phys. Rev. D 68 (2003) 054013, (arXiv:hep-ph/0305118); S. Ciulli, C. Sebu, K. Schilcher and H. Spiesberger, Phys. Lett. B 595 (2004) 359, (arXiv:hep-ph/0312212). S. Narison, (arXiv:hep-ph/0412152)]. Precise knowledge of these condensates is of relevance in kaon decays [M. Knecht, S. Peris and E. de Rafael, Phys. Lett. B 457 (1999) 227, (arXiv:hep-ph/9812471); J.F. Donoghue and E. Golowich, Phys. Lett. B 478 (2000) 172, (arXiv:hep-ph/9911309); M. Knecht, S. Peris and E. de Rafael, Phys. Lett. B 508 (2001) 117, (arXiv:hep-ph/0102017)] and therefore it seems mandatory to assess the actual impact of what is commonly neglected in spectral sum rules, most prominently the issue of duality violations. We will explicitly compute them in a toy model and show that they are a priori non-negligible

Novel Perspectives from Light-Front QCD, Super-Conformal Algebra, and Light-Front Holography

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

2015-12-01

Light-Front Quantization – Dirac’s “Front Form” – provides a physical, frame-independent formalism for hadron dynamics and structure. Observables such as structure functions, transverse momentum distributions, and distribution amplitudes are defined from the hadronic LFWFs. One obtains new insights into the hadronic mass scale, the hadronic spectrum, and the functional form of the QCD running coupling in the nonperturbative domain using light-front holography. In addition, superconformal algebra leads to remarkable supersymmetric relations between mesons and baryons. I also discuss evidence that the antishadowing of nuclear structure functions is nonuniversal; i.e., flavor dependent, and why shadowing and antishadowing phenomena may be incompatible with the momentum and other sum rules for the nuclear parton distribution functions.

Inhomogeneous spectral moment sum rules for the retarded Green function and self-energy of strongly correlated electrons or ultracold fermionic atoms in optical lattices

International Nuclear Information System (INIS)

Freericks, J. K.; Turkowski, V.

2009-01-01

Spectral moment sum rules are presented for the inhomogeneous many-body problem described by the fermionic Falicov-Kimball or Hubbard models. These local sum rules allow for arbitrary hoppings, site energies, and interactions. They can be employed to quantify the accuracy of numerical solutions to the inhomogeneous many-body problem such as strongly correlated multilayered devices, ultracold atoms in an optical lattice with a trap potential, strongly correlated systems that are disordered, or systems with nontrivial spatial ordering such as a charge-density wave or a spin-density wave. We also show how the spectral moment sum rules determine the asymptotic behavior of the Green function, self-energy, and dynamical mean field when applied to the dynamical mean-field theory solution of the many-body problem. In particular, we illustrate in detail how one can dramatically reduce the number of Matsubara frequencies needed to solve the Falicov-Kimball model while still retaining high precision, and we sketch how one can incorporate these results into Hirsch-Fye quantum Monte Carlo solvers for the Hubbard (or more complicated) models. Since the solution of inhomogeneous problems is significantly more time consuming than periodic systems, efficient use of these sum rules can provide a dramatic speed up in the computational time required to solve the many-body problem. We also discuss how these sum rules behave in nonequilibrium situations as well, where the Hamiltonian has explicit time dependence due to a driving field or due to the time-dependent change in a parameter such as the interaction strength or the origin of the trap potential.

Dispersion theory and sum rules for the non-minimum phase problem in optical spectroscopy

International Nuclear Information System (INIS)

Peiponen, Kai-Erik

2009-01-01

Dispersion relations and sum rules for integer powers of an optical response function are given in the case of the non-minimum phase problem. These relations were obtained using the concept of the Hilbert transform and Blaschke product. The theory presented in this paper is useful both in basic and applied studies of non-minimum phase functions in optics, and also other fields of physics such as high energy physics.

Gottfried sum rule and mesonic exchanges in deuteron

International Nuclear Information System (INIS)

Kaptari, L.P.

1991-01-01

Recent NMC data on the experimental value of the Gottfried Sum are discussed. It is shown that the Gottfried Sum is sensitive to the nuclear structure corrections, viz. themesonic exchanges and binding effects. A new estimation of the Gottfried Sum is given. The obtained result is close to the quark-parton prediction of 1/3. 11 refs.; 2 figs

QCD-based pion distribution amplitudes confronting experimental data

International Nuclear Information System (INIS)

Bakulev, A.P.; Mikhajlov, S.V.; Stefanis, N.G.

2001-01-01

We use QCD sum rules with nonlocal condensates to recalculate more accurately the moments and their confidence intervals of the twist-2 pion distribution amplitude including radiative corrections. We are thus able to construct an admissible set of pion distribution amplitudes which define a reliability region in the a 2 , a 4 plane of the Gegenbauer polynomial expansion coefficients. We emphasize that models like that of Chernyak and Zhitnitsky, as well as the asymptotic solution, are excluded from this set. We show that the determined a 2 , a 4 region strongly overlaps with that extracted from the CLEO data by Schmedding and Yakovlev and that this region is also not far from the results of the first direct measurement of the pion valence quark momentum distribution by the Fermilab E791 collaboration. Comparisons with recent lattice calculations and instanton-based models are briefly discussed

Splitting of electrons and violation of the Luttinger sum rule

Science.gov (United States)

Quinn, Eoin

2018-03-01

We obtain a controlled description of a strongly correlated regime of electronic behavior. We begin by arguing that there are two ways to characterize the electronic degree of freedom, either by the canonical fermion algebra or the graded Lie algebra su (2 |2 ) . The first underlies the Fermi liquid description of correlated matter, and we identify a regime governed by the latter. We exploit an exceptional central extension of su (2 |2 ) to employ a perturbative scheme recently developed by Shastry and obtain a series of successive approximations for the electronic Green's function. We then focus on the leading approximation, which reveals a splitting in two of the electronic dispersion. The Luttinger sum rule is violated, and a Mott metal-insulator transition is exhibited. We offer a perspective.

Adler-type sum rule, charge symmetry and neutral current in general multi-triplet model

International Nuclear Information System (INIS)

Katuya, Mituaki; Baba, Yoshimitsu; Fujii, Kanji

1975-01-01

We derive Adler-type sum rule extended to general multi-triplet model. Paying attention to roles of the colour degree of freedom, we discuss the charge symmetry property of the weak charged current and the structure functions for ν(ν - )+N→l(l - )+X, and also the structure of the neutral current. A comment is given on implications in our theory of Koike and Konuma's result on the neutral hadronic current. (auth.)

Parton distributions, the Gottfried sum rule and the W charge asymmetry

International Nuclear Information System (INIS)

Martin, A.D.; Stirling, W.J.; Roberts, R.G.

1990-09-01

Preliminary data from the New Muon Collaboration (NMC) allow a precise evaluation of I p-n (x) from a given integral formula for values of x down to 0.004. As x → 0, this integral should converge to a value I p-n (0) = 1/3 (Gottfried sum rule) if the light sea-quark distributions are equal. The NMC value I p-n (0.004) = 0.23 ± 0.03, though appearing to be well short of 1/3, is quite consistent with modern estimates for parton distributions extracted from a wide range of data. These parton distributions are also found to reproduce the W ± rapidity asymmetry recently measured by a European collaboration. (author)

The QCD/SM working group: Summary report

International Nuclear Information System (INIS)

Giele, W.

2004-01-01

Quantum Chromo-Dynamics (QCD), and more generally the physics of the Standard Model (SM), enter in many ways in high energy processes at TeV Colliders, and especially in hadron colliders (the Tevatron at Fermilab and the forthcoming LHC at CERN), First of all, at hadron colliders, QCD controls the parton luminosity, which rules the production rates of any particle or system with large invariant mass and/or large transverse momentum. Accurate predictions for any signal of possible ''New Physics'' sought at hadron colliders, as well as the corresponding backgrounds, require an improvement in the control of uncertainties on the determination of PDF and of the propagation of these uncertainties in the predictions. Furthermore, to fully exploit these new types of PDF with uncertainties, uniform tools (computer interfaces, standardization of the PDF evolution codes used by the various groups fitting PDF's) need to be proposed and developed. The dynamics of colour also affects, both in normalization and shape, various observables of the signals of any possible ''New Physics'' sought at the TeV scale, such as, e.g. the production rate, or the distributions in transverse momentum of the Higgs boson. Last, but not least, QCD governs many backgrounds to the searches for this ''New Physics''. Large and important QCD corrections may come from extra hard parton emission (and the corresponding virtual corrections), involving multi-leg and/or multi-loop amplitudes. This requires complex higher order calculations, and new methods have to be designed to compute the required multi-legs and/or multi-loop corrections in a tractable form. In the case of semi-inclusive observables, logarithmically enhanced contributions coming from multiple soft and collinear gluon emission require sophisticated QCD resummation techniques. Resummation is a catch-all name for efforts to extend the predictive power of QCD by summing the large logarithmic corrections to all orders in perturbation theory. In

The QCD/SM working group: Summary report

Energy Technology Data Exchange (ETDEWEB)

W. Giele et al.

2004-01-12

Quantum Chromo-Dynamics (QCD), and more generally the physics of the Standard Model (SM), enter in many ways in high energy processes at TeV Colliders, and especially in hadron colliders (the Tevatron at Fermilab and the forthcoming LHC at CERN), First of all, at hadron colliders, QCD controls the parton luminosity, which rules the production rates of any particle or system with large invariant mass and/or large transverse momentum. Accurate predictions for any signal of possible ''New Physics'' sought at hadron colliders, as well as the corresponding backgrounds, require an improvement in the control of uncertainties on the determination of PDF and of the propagation of these uncertainties in the predictions. Furthermore, to fully exploit these new types of PDF with uncertainties, uniform tools (computer interfaces, standardization of the PDF evolution codes used by the various groups fitting PDF's) need to be proposed and developed. The dynamics of colour also affects, both in normalization and shape, various observables of the signals of any possible ''New Physics'' sought at the TeV scale, such as, e.g. the production rate, or the distributions in transverse momentum of the Higgs boson. Last, but not least, QCD governs many backgrounds to the searches for this ''New Physics''. Large and important QCD corrections may come from extra hard parton emission (and the corresponding virtual corrections), involving multi-leg and/or multi-loop amplitudes. This requires complex higher order calculations, and new methods have to be designed to compute the required multi-legs and/or multi-loop corrections in a tractable form. In the case of semi-inclusive observables, logarithmically enhanced contributions coming from multiple soft and collinear gluon emission require sophisticated QCD resummation techniques. Resummation is a catch-all name for efforts to extend the predictive power of QCD by summing the large

Observables of QCD diffraction

Science.gov (United States)

Mieskolainen, Mikael; Orava, Risto

2017-03-01

A new combinatorial vector space measurement model is introduced for soft QCD diffraction. The model independent mathematical construction resolves experimental complications; the theoretical framework of the approach includes the Good-Walker view of diffraction, Regge phenomenology together with AGK cutting rules and random fluctuations.

Phase transitions and flux distributions of SU(2) lattice gauge theory

International Nuclear Information System (INIS)

Peng, Yingcai.

1993-01-01

The strong interactions between quarks are believed to be described by Quantum Chromodynamics (QCD), which is a non-abelian SU(3) gauge theory. It is known that QCD undergoes a deconfining phase transition at very high temperatures, that is, at low temperatures QCD is in confined phase, at sufficient high temperatures it is in an unconfined phase. Also, quark confinement is believed to be due to string formation. In this dissertation the authors studied SU(2) gauge theory using numerical methods of LGT, which will provide some insights about the properties of QCD because SU(2) is similar to SU(3). They measured the flux distributions of a q bar q pair at various temperatures in different volumes. They find that in the limit of infinite volumes the flux distribution is different in the two phases. In the confined phase strong evidence is found for the string formation, however, in the unconfined phase there is no string formation. On the other hand, in the limit of zero temperature and finite volumes they find a clear signal for string formation in the large volume region, however, the string tension measured in intermediate volumes is due to finite volume effects, there is no intrinsic string formation. The color flux energies (action) of the q bar q pair are described by Michael sum rules. The original Michael sum rules deal with a static q bar q pair at zero temperature in infinite volumes. To check these sum rules with flux data at finite temperatures, they present a complete derivation for the sum rules, thus generalizing them to account for finite temperature effects. They find that the flux data are consistent with the prediction of generalized sum rules. The study elucidates the rich structures of QCD, and provides evidence for quark confinement and string formation. This supports the belief that QCD is a correct theory for strong interactions, and quark confinement can be explained by QCD

Nearly perturbative lattice-motivated QCD coupling with zero IR limit

Science.gov (United States)

Ayala, César; Cvetič, Gorazd; Kögerler, Reinhart; Kondrashuk, Igor

2018-03-01

The product of the gluon dressing function and the square of the ghost dressing function in the Landau gauge can be regarded to represent, apart from the inverse power corrections 1/{Q}2n, a nonperturbative generalization { \\mathcal A }({Q}2) of the perturbative QCD running coupling a({Q}2) (\\equiv {α }s({Q}2)/π ). Recent large volume lattice calculations for these dressing functions indicate that the coupling defined in such a way goes to zero as { \\mathcal A }({Q}2)∼ {Q}2 when the squared momenta Q 2 go to zero ({Q}2\\ll 1 {GeV}}2). In this work we construct such a QCD coupling { \\mathcal A }({Q}2) which fulfills also various other physically motivated conditions. At high momenta it becomes the underlying perturbative coupling a({Q}2) to a very high precision. And at intermediate low squared momenta {Q}2∼ 1 {GeV}}2 it gives results consistent with the data of the semihadronic τ lepton decays as measured by OPAL and ALEPH. The coupling is constructed in a dispersive way, resulting as a byproduct in the holomorphic behavior of { \\mathcal A }({Q}2) in the complex Q 2-plane which reflects the holomorphic behavior of the spacelike QCD observables. Application of the Borel sum rules to τ-decay V + A spectral functions allows us to obtain values for the gluon (dimension-4) condensate and the dimension-6 condensate, which reproduce the measured OPAL and ALEPH data to a significantly better precision than the perturbative \\overline{MS}} coupling approach.

A toolbox for Harmonic Sums and their analytic continuations

Energy Technology Data Exchange (ETDEWEB)

Ablinger, Jakob; Schneider, Carsten [RISC, J. Kepler University, Linz (Austria); Bluemlein, Johannes [DESY, Zeuthen (Germany)

2010-07-01

The package HarmonicSums implemented in the computer algebra system Mathematica is presented. It supports higher loop calculations in QCD and QED to represent single-scale quantities like anomalous dimensions and Wilson coefficients. The package allows to reduce general harmonic sums due to their algebraic and different structural relations. We provide a general framework for these reductions and the explicit representations up to weight w=8. For the use in experimental analyzes we also provide an analytic formalism to continue the harmonic sums form their integer arguments into the complex plane, which includes their recursions and asymptotic representations. The main ideas are illustrated by specific examples.

Density-dependent Hartree-Fock response functions in quasi-elastic electron scattering on 12C and related sum rules

International Nuclear Information System (INIS)

Kohno, M.

1983-01-01

We report fully consistent calculations of the longitudinal and transverse response functions of the inclusive quasi-elastic electron scattering on 12 C in the Hartree-Fock approximation. The distorted wave for the outgoing nucleon is constructed from the same non-local Hartree-Fock field as in the ground-state description. Thus the orthogonality and Pauli principle requirements are naturally satisfied. The theoretical prediction, based on the standard density-dependent effective interaction (GO force), shows a good correspondence to the experimental data. Since the calculated response functions automatically satisfy the relevant sum rule, this work illuminates the well-known puzzle concerning the longitudinal part, which remains to be solved. We study the energy-weighted sum rules and discuss effects beyond the mean-field approximation. Meson-exchange-current contributions to the transverse response function are also estimated and found to be small due to cancellations among them. (orig.)

Wong's equations and the small x effective action in QCD

International Nuclear Information System (INIS)

Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju

2001-01-01

We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x

Wong's equations and the small x effective action in QCD

International Nuclear Information System (INIS)

Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju

2000-01-01

We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x

Unambiguity of renormalization group calculations in QCD

International Nuclear Information System (INIS)

Vladimirov, A.A.

1979-01-01

A detailed analysis of the reduction of ambiguities determined by an arbitrary renormalization scheme is presented for the renormalization group calculations of physical quantities in quantum chromodynamics (QCD). Some basic formulas concerning the renormalization-scheme dependence of Green's and renormalization group functions are given. A massless asymptotically free theory with one coupling constant g is considered. In conclusion, several rules for renormalization group calculations in QCD are formulated

AdS/QCD, LIight-Front Holography, and the Non-perturbative Running Coupling

Energy Technology Data Exchange (ETDEWEB)

Brodsky, Stanley J.; /SLAC; de Teramond, Guy; /Costa Rica U.; Deur, Alexandre; /Jefferson Lab

2010-04-29

The combination of Anti-de Sitter space (AdS) methods with light-front (LF) holography provides a remarkably accurate first approximation for the spectra and wavefunctions of meson and baryon light-quark bound states. The resulting bound-state Hamiltonian equation of motion in QCD leads to relativistic light-front wave equations in terms of an invariant impact variable {zeta} which measures the separation of the quark and gluonic constituents within the hadron at equal light-front time. These equations of motion in physical space-time are equivalent to the equations of motion which describe the propagation of spin-J modes in anti-de Sitter (AdS) space. The eigenvalues give the hadronic spectrum, and the eigenmodes represent the probability distributions of the hadronic constituents at a given scale. A positive-sign confining dilaton background modifying AdS space gives a very good account of meson and baryon spectroscopy and form factors. The light-front holographic mapping of this model also leads to a non-perturbative effective coupling {alpha}{sub s}{sup Ads} (Q{sup 2}) which agrees with the effective charge defined by the Bjorken sum rule and lattice simulations. It displays a transition from perturbative to nonperturbative conformal regimes at a momentum scale {approx} 1 GeV. The resulting {beta}-function appears to capture the essential characteristics of the full {beta}-function of QCD, thus giving further support to the application of the gauge/gravity duality to the confining dynamics of strongly coupled QCD.

Strong interaction at finite temperature

Indian Academy of Sciences (India)

The first one is the general method of chiral perturbation theory, which may be readily applied to this problem. The other is the method of thermal QCD sum rules. We show that, when the spectral sides of the sum rules are calculated correctly, they do not lead to any new results, but reproduce those of the vacuum sum rules.

Effect of Coulomb interaction on the X-ray magnetic circular dichroism spin sum rule in rare earths

NARCIS (Netherlands)

Teramura, Y; Tanaka, A; Thole, BT; Jo, T

A deviation from the spin sum rule, which relates the integrated intensity of the X-ray magnetic circular dichroism (MCD) signal to the expectation value of the spin operator S-z ((S-z)), is numerically calculated in the case of the 3d --> 4f absorption for rare earths from the trivalent Ce to Tm.

New COMPASS results on the spin structure function $g_1^p$, and QCD fit

CERN Document Server

Wilfert, Malte

2014-01-01

The COMPASS experiment at CERN SPS has taken data with a polarised muon beam scattering off a polarised NH 3 target in 2011. The beam energy has been increased to 200 GeV compared to 160 GeV in 2007 and thus, higher values of Q 2 and lower values of x are reached. From these data the longitudinal double spin asymmetry A p 1 and the spin-dependent structure function g p 1 are extracted. The results are used in a NLO QCD fit to the world data to obtain the polarised parton distributions and also to test the Bjorken sum rule, connecting the integral of the non-singlet structure function with the ratio of the weak coupling constants

Phenomenological study of the QCD vacuum. Problems relevant to factorizability of four-fermion operators

International Nuclear Information System (INIS)

Zhitnitskij, A.R.

1985-01-01

The method of QCD sum rules is used here to evaluate vacuUm expectation values (VEV) for various four-fermion operators. It is found that the VEV (anti uσsub(μν) lambda sup(α)d anti d σsub(μν) lambda sup(α)u) is by a factor of 3-3.5 larger than the factorized quantity, while the VEV (anti u lambda sup(α) d anti d lambda sup(α) u) is smaller by a factor of 3-5 A by-product of the work is a phenomenological estimate for the VEV (gsup(3)fsup(abc)Gsub(μν)sup(α)Gsub(ν lambda)sup(b)Gsub(lambda μ)sup(c)) approximately equal to 0.06 GeV 6

The $\\Delta I = 1/2 $ Rule in the Light of Two-Dimensional QCD

CERN Document Server

Ellis, John R.; Hanany, Amihay; Karliner, Marek; Ellis, John; Frishman, Yitzhak; Hanany, Amihay; Karliner, Marek

1997-01-01

We calculate in QCD$_2$ the ratios of baryonic matrix elements of $\\Delta I = 2$ and $\\Delta I = 0$ four-fermion operators, with a view to understanding better the mechanism of $\\Delta I = 1/2$ enhancement in QCD$_4$. We find relatively small suppressions of both the scalar-scalar and vector-vector these results, in view of a suggestion that gluon condensation may be an important contributing factor in the $\\Delta I = 1/2$ enhancement seen in QCD$_4$. At the technical level, our calculation of the vector-vector operator matrix element requires a treatment of the time dependence of the QCD$_2$ soliton which had not been developed in previous phenomenological calculations within this model.

Surface thickness effects and splitting of multipole excitations in deformed nuclei. [Sum rule, hydrodynamic model

Energy Technology Data Exchange (ETDEWEB)

Christillin, P [Scuola Normale Superiore, Pisa (Italy); Lipparini, E; Stringari, S [Dipartimento Matematica e Fisica, Trento, Italy

1978-09-25

A sum-rule approach is used to study the influence of surface thickness upon the splitting of dipole and isoscalar quadrupole energies in deformed nuclei. It is shown that hydrodynamic model results are recovered in the case of a deformed skin thickness. A constant skin thickness leads in the dipole case to slightly different predictions which seem in better agreement with experiments. The splitting of the isoscalar quadrupole mode is not sensitive to the surface thickness shape.

Final COMPASS results on the deuteron spin-dependent structure function g1d and the Bjorken sum rule

Directory of Open Access Journals (Sweden)

C. Adolph

2017-06-01

Full Text Available Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a 6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c24GeV/c2 in the mass of the hadronic final state. The deuteron double-spin asymmetry A1d and the deuteron longitudinal-spin structure function g1d are presented in bins of x and Q2. Towards lowest accessible values of x, g1d decreases and becomes consistent with zero within uncertainties. The presented final g1d values together with the recently published final g1p values of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1 world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾ renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c2=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1d constitute the COMPASS legacy on the measurements of g1 through inclusive spin-dependent deep inelastic scattering.

Normalization sum rule and spontaneous breaking of U(N) invariance in random matrix ensembles

International Nuclear Information System (INIS)

Canali, C.M.; Kravtsov, V.E.

1995-03-01

It is shown that the two-level correlation function R(s,s') in the invariant random matrix ensembles (RME) with soft confinement exhibits a ''ghost peak'' at s approx. -s'. This lifts the sum rule prohibition for the level number variance to have a Poisson-like term var(n) = ηn that is typical of RME with broken U(N) symmetry. Thus we conclude that the U(N) invariance is broken spontaneously in the RME with soft confinement, η playing the role of an order-parameter. (author). 16 refs, 1 fig

Sum rule and hydrodynamic analyses of the velocity autocorrelation function in strongly coupled plasmas

International Nuclear Information System (INIS)

Nagano, Seido; Ichimaru, Setsuo

1980-01-01

The memory function for the velocity autocorrelation function in a strongly coupled, one-component plasma is analyzed in the short time and long time domains, respectively, with the aid of the frequency-moment sum rules and the hydrodynamic consideration evoking the idea of the generalized Stokes friction. A series of interpolation schemes with successively improved accuracies are then introduced. Numerical investigations of those interpolation schemes clarify the physical origin of the three different types of the velocity autocorrelation function observed in the molecular dynamics simulation at different regimes of the coupling constant. (author)

How Precisely can we Determine the $\\piNN$ Coupling Constant from the Isovector GMO Sum Rule?

CERN Document Server

Loiseau, B; Thomas, A W

1999-01-01

The isovector GMO sum rule for zero energy forward pion-nucleon scattering iscritically studied to obtain the charged pion-nucleon coupling constant usingthe precise negatively charged pion-proton and pion-deuteron scattering lengthsdeduced recently from pionic atom experiments. This direct determination leadsto a pseudoscalar charged pion-nucleon coupling constant of 14.23 +- 0.09(statistic) +- 0.17 (systematic). We obtain also accurate values for thepion-nucleon scattering lengths.

Deep inelastic scattering and light-cone wave functions

International Nuclear Information System (INIS)

Belyaev, V.M.; Johnson, M.B.

1996-01-01

In the framework of light-cone QCD rules, we study the valence quark distribution function q(x B ) of a pion for moderate x B . The sum rule with the leading twist-2 wave function gives q(x B ) = φ π (x B ). Twist-4 wave functions give about 30% for x B ∼0.5. It is shown that QCD sum rule predictions, with the asymptotic pion wave function, are in good agreement with experimental data. We found that a two-hump profile for the twist-2 wave function leads to a valence quark distribution function that contradicts experimental data

QCD, OZI, and evidence for glueballs

International Nuclear Information System (INIS)

Lindenbaum, S.J.

1981-01-01

The characteristics expected from low Q-QCD for the behavior of glueballs and the OZI rule is discussed. The reaction π - p → phi phi n represents on OZI forbidden (hairpin) diagram. It has been observed at the Brookhaven National Laboratory multiparticle spectrometer by the Brookhaven National Laboratory/City College of New York group. The author has shown that the expected OZI suppression is essentially entirely absent and in fact the Isobar Model which does not contain OZI suppression quantitatively explains the observed results. A general evaluation of the special characteristics of the data compared to other related reactions plus the foregoing facts leads the author to conclude that the intervention of glueball resonances is the likely explanation in the context of QCD. Other explanations are shown to be improbable. In particular the hypothesis that decay of a radial excitation of the eta' is responsible for lack of OZI suppression is ruled out. Planned experiments with the purpose of explicity discovering glueballs will be discussed. The OZI rule peculiarities such as violation of crossing symmetry and unitarity are attributed to color confinement

QCD, OZI, and evidence for glueballs

Energy Technology Data Exchange (ETDEWEB)

Lindenbaum, S.J.

1981-01-01

The characteristics expected from low Q-QCD for the behavior of glueballs and the OZI rule is discussed. The reaction ..pi../sup -/p ..-->.. phi phi n represents on OZI forbidden (hairpin) diagram. It has been observed at the Brookhaven National Laboratory multiparticle spectrometer by the Brookhaven National Laboratory/City College of New York group. The author has shown that the expected OZI suppression is essentially entirely absent and in fact the Isobar Model which does not contain OZI suppression quantitatively explains the observed results. A general evaluation of the special characteristics of the data compared to other related reactions plus the foregoing facts leads the author to conclude that the intervention of glueball resonances is the likely explanation in the context of QCD. Other explanations are shown to be improbable. In particular the hypothesis that decay of a radial excitation of the eta' is responsible for lack of OZI suppression is ruled out. Planned experiments with the purpose of explicity discovering glueballs will be discussed. The OZI rule peculiarities such as violation of crossing symmetry and unitarity are attributed to color confinement.

Isospin breaking in nuclear physics: The Nolen-Schiffer effect

International Nuclear Information System (INIS)

Adami, C.; Brown, G.E.

1991-01-01

Using the QCD sum rules we calculate the neutron-proton mass difference at zero density as a function of the difference in bare quark mass m d -m u . We confirm results of Hatsuda, Hoegaasen and Prakash that the largest term results from the difference in up and down quark condensates, the explicit C (m d -m u ) entering with the opposite sign. The quark condensates are then extended to finite density to estimate the Nolen-Schiffer effect. The neutron-proton mass difference is extremely density dependent, going to zero at roughly nuclear matter density. The Ioffe formula for the nucleon mass is interpreted as a derivation, within the QCD sum rule approach, of the Nambu-Jona-Lasinio formula. This clarifies the N c counting and furthermore provides an alternative interpretation of the Borel mass. We compare calculations in the constituent quark model treated in the Nambu-Jona-Lasinio formalism with ours in the QCD sum rule approach. (orig.)

Fixed poles in electromagnetic processes and modification of Adler's neutrino sum rule due to quark anomalous magnetic moment

International Nuclear Information System (INIS)

Khare, A.

1975-01-01

We show that Adler's sum rule for neutrino scattering and Bjorken's inequality for electron-proton scattering are modified if quark has finite anomalous magnetic moment ksub(q). We also show that if ksub(q) is nonzero, there exist fixed poles in spin-flip Compton scattering as well as in charged pion photoproduction. (auth.)

Analysis of diffractive pd to Xd and pp to Xp interactions and test of the finite-mass sum rule

CERN Document Server

Akimov, Y; Golovanov, L B; Goulianos, K; Gross, D; Malamud, E; Melissinos, A C; Mukhin, S; Nitz, D; Olsen, S; Sticker, H; Tsarev, V A; Yamada, R; Zimmerman, P

1976-01-01

The first moment finite mass sum rule is tested by utilising cross- sections for pp to Xp extracted from recent Fermilab data on pd to Xd and also comparing with CERN ISR data. The dependences on M/sub x//sup 2/, t and s are also discussed. (11 refs).

Radiative transitions in quarkonjum and quantum chromodynamics

International Nuclear Information System (INIS)

Khodjamirian, A.Yu.

1980-01-01

A new approach to the radiative transitions in quarkonium (c, anti c, b anti b, ...) based on the asymptotic freedom of QCD and on the analyticity is proposed. This approach consists in derivation of dispersion sum rules relating the transition amplitudes with triangle quark diagrams. In this way, a possibility emerges to estimate these amplitudes in a model-independent way. The sum rules are obtained in zeroth order of QCD for transitions between C-even levels 0 ++ , 1 ++ , 2 ++ , 0 -+ and vector (1 -- ) levels. The influence of gluon corrections is discussed and the optimum moments of sum rules are chosen for which these corrections are expected to be at the level of O(αsub(s)) approximately 20%. The widths of radiative transitions in charmonium calculated by means of sum rules turn out to be in agreement with available experimental data. The estimates for analogous transitions in b-quarkonium are also presented. The suggested approach is compared with nonrelativistic models of radiative transitions [ru

Sum rules for the ed - NN scattering reactions and microscopic potential field-theoretical approach

International Nuclear Information System (INIS)

Machivariani, A.I.

1996-01-01

The connections between the equal-time commutators of nucleon and photon field-operators and relativistic potential approach of ed - NN scattering equations is established. Namely, it is demonstrated that: 1) equal-time commutator between nucleon field operators generated completeness condition for NN interaction functions, 2) the off-mass shell contributions in γd - NN exchange currents or in microscopic NN potential are determined by equal time commutator between nucleon field operator and photon or nucleon source operators, and 3) equal-time commutators between source operators produce sum rules for same vertex functions and effective potentials [ru

Sum rules application to reflectometry of X-ray resonant radiation for magnetic multilayer investigation

International Nuclear Information System (INIS)

Smekhova, A.G.; Andreeva, M.A.

2005-01-01

One elaborated the general formalism on the basis of which one derived the clear expressions for reflection factors of X-ray radiation with a circular polarization from medium magnetized both within surface plane and within reflection plane both for grazing angles and for high grazing angles. The asymmetry of reflection spectra for right- and left-polarized radiation is shown to depend both on nondiagonal components of a susceptibility tensor and on other components in contrast to absorption spectra, so the sum rule to determine the orbital and the spin magnetic moments can not be applied directly to the experimental spectra of reflection [ru

Correlation of zero-point energy with molecular structure and molecular forces. 3. Approximation for H/D isotope shifts and linear frequency sum rule

International Nuclear Information System (INIS)

Oi, T.; Ishida, T.

1984-01-01

The approximation methods for the zero-point energy (ZPE) previously developed using the Lanczo's tau method have been applied to the shifts in ZPE due to hydrogen isotope substitutions. Six types of approximation methods have been compared and analyzed on the basis of a weighing function Ω(lambda) varies as lambda/sup k/ and the actual eigenvalue shift spectra. The method generated by the most general optimzation treatment yields a predictable and generally satisfactory precision of the order of 1% or better. A linear frequency sum rule has been derived, which approximately holds for the sets of isotopic molecules which satisfy the second-order frequency sum rule. 19 references, 3 figures, 3 tables

L-edge sum rule analysis on 3d transition metal sites: from d10 to d0 and towards application to extremely dilute metallo-enzymes.

Science.gov (United States)

Wang, Hongxin; Friedrich, Stephan; Li, Lei; Mao, Ziliang; Ge, Pinghua; Balasubramanian, Mahalingam; Patil, Daulat S

2018-03-28

According to L-edge sum rules, the number of 3d vacancies at a transition metal site is directly proportional to the integrated intensity of the L-edge X-ray absorption spectrum (XAS) for the corresponding metal complex. In this study, the numbers of 3d holes are characterized quantitatively or semi-quantitatively for a series of manganese (Mn) and nickel (Ni) complexes, including the electron configurations 3d 10 → 3d 0 . In addition, extremely dilute (edge jump region; and (2) by adding an inert tracer to the sample that provides a prominent spectral feature to replace the weak edge jump for intensity normalization. In this publication, we present for the first time: (1) L-edge sum rule analysis for a series of Mn and Ni complexes that include electron configurations from an open shell 3d 0 to a closed shell 3d 10 ; (2) a systematic analysis on the uncertainties, especially on that from the edge jump, which was missing in all previous reports; (3) a clearly-resolved edge jump between pre-L 3 and post-L 2 regions from an extremely dilute sample; (4) an evaluation of an alternative normalization standard for L-edge sum rule analysis. XAS from two copper (Cu) proteins measured using a conventional semiconductor X-ray detector are also repeated as bridges between Ni complexes and dilute Ni enzymes. The differences between measuring 1% Cu enzymes and measuring edge sum rule analysis to virtually any 3d metal complex and any dilute biological samples that contain 3d metals.

Wong's equations and the small x effective action in QCD

Energy Technology Data Exchange (ETDEWEB)

Jalilian-Marian, Jamal; Jeon, Sangyong; Venugopalan, Raju

2000-07-13

We propose a new form for the small x effective action in QCD. This form of the effective action is motivated by Wong's equations for classical, colored particles in non-Abelian background fields. We show that the BFKL equation, which sums leading logarithms in x, is efficiently reproduced with this form of the action. We argue that this form of the action may be particularly useful in computing next-to-leading-order results in QCD at small x.

The Adler-Weisberger and Goldberger-Miyazawa-Oehme sum rules as probes of constraints from analyticity and chiral symmetry in dynamical models for pion-nucleon scattering

International Nuclear Information System (INIS)

Kondratyuk, S.; Kubodera, K.; Myhrer, F.; Scholten, O.

2004-01-01

The Adler-Weisberger and Goldberger-Miyazawa-Oehme sum rules are calculated within a relativistic, unitary and crossing symmetric dynamical model for pion-nucleon scattering using two different methods: (1) by evaluating the scattering amplitude at the corresponding low-energy kinematics and (2) by evaluating the sum-rule integrals with the calculated total cross section. The discrepancy between the results of the two methods provides a measure of the breaking of analyticity and chiral symmetry in the model. The contribution of the Δ resonance, including its dressing with meson loops, is discussed in some detail and found to be small

Many body effects in nuclear matter QCD sum rules

Science.gov (United States)

Drukarev, E. G.; Ryskin, M. G.; Sadovnikova, V. A.

2017-12-01

We calculate the single-particle nucleon characteristics in symmetric nuclear matter with inclusion of the 3N and 4N interactions. We calculated the contribution of the 3N interactions earlier, now we add that of the 4N ones. The contribution of the 4N forces to nucleon self energies is expressed in terms of the nonlocal scalar condensate (d = 3) and of the configurations of the vector-scalar and the scalar-scalar quark condensates (d = 6) in which two diquark operators act on two different nucleons of the matter.These four-quark condensates are obtained in the model-independent way. The density dependence of the nucleon effective mass, of the vector self energy and of the single-particle potential energy are obtained. We traced the dependence of the nucleon characteristics on the actual value of the pion-nucleon sigma term. We obtained also the nucleon characteristics in terms of the quasifree nucleons, with the noninteracting nucleons surrounded by their pion clouds as the starting point. This approach leads to strict hierarchy of the many body forces.

What can we learn from polarized structure function data?

CERN Document Server

Ball, Richard D.; Altarelli, Guido; Forte, Stefano; Ball, Richard D.; Ridolfi, Giovanni; Altarelli, Guido; Forte, Stefano

1997-04-20

We summarise the perturbative QCD analysis of the structure function data for g_1 from longitudinally polarized deep inelastic scattering from proton, deuteron and neutron targets, with particular emphasis on testing sum rules, determining helicity fractions, and extracting the strong coupling from both scaling violations and the Bjorken sum rule.

Setting the renormalization scale in QCD: The principle of maximum conformality

DEFF Research Database (Denmark)

Brodsky, S. J.; Di Giustino, L.

2012-01-01

A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale mu of the running coupling alpha(s)(mu(2)). The purpose of the running coupling in any gauge theory is to sum all terms involving the beta function; in fact, when the renormali......A key problem in making precise perturbative QCD predictions is the uncertainty in determining the renormalization scale mu of the running coupling alpha(s)(mu(2)). The purpose of the running coupling in any gauge theory is to sum all terms involving the beta function; in fact, when...... the renormalization scale is set properly, all nonconformal beta not equal 0 terms in a perturbative expansion arising from renormalization are summed into the running coupling. The remaining terms in the perturbative series are then identical to that of a conformal theory; i.e., the corresponding theory with beta...... = 0. The resulting scale-fixed predictions using the principle of maximum conformality (PMC) are independent of the choice of renormalization scheme-a key requirement of renormalization group invariance. The results avoid renormalon resummation and agree with QED scale setting in the Abelian limit...

The Adler-Weisberger sum rule and the sigma-Commutator for the Kaon-Neutron system

International Nuclear Information System (INIS)

Rodriguez-Vargas, A.M.; Violini, G.

1980-01-01

The axial coupling constant is determined from Kp and Kn Adler-Weisberger sum rule, in correspondence with different anti K N unphysical region parameterizations. Moreover a new calculation of the sigma-term is presented. It is shown that by using Kn data it is possible to reduce considerably the error on sigma sup(KK)sub(NN) with respect to the analogous calculation for Kp, but that an accurate determination requires a good value for the psub(3/2) anti K N scattering length. By preferring the solutions which lead to a positive sigma-term, one obtains sigma sup(KK)sub(NN) = 638 +- 438 MeV. (orig.) 891 HSI/orig. 892 HIS

On the anomalous skin effect in metals. II. Some aspects of superconductors, sum-rule applications and limits of this technique

Energy Technology Data Exchange (ETDEWEB)

Drangeid, K E; Sommerhalder, R [IBM Research Lab., Zurich (Switzerland)

1976-03-02

Based on previous work applying to normal conducting metals, an analog network model for superconducting metals is developed. The reciprocal surface impendance associated with this model is used as a response function in connection with the Kramers-Kronig relations and the sum rule to compute electrodynamic properties of superconductors.

Near-threshold deuteron photodisintegration: An indirect determination of the Gerasimov-Drell-Hearn sum rule and forward spin polarizability (γ0) for the deuteron at low energies

International Nuclear Information System (INIS)

Ahmed, M. W.; Blackston, M. A.; Perdue, B. A.; Tornow, W.; Weller, H. R.; Norum, B.; Sawatzky, B.; Prior, R. M.; Spraker, M. C.

2008-01-01

It is shown that a measurement of the analyzing power obtained with linearly polarized γ-rays and an unpolarized target can provide an indirect determination of two physical quantities. These are the Gerasimov-Drell-Hearn (GDH) sum rule integrand for the deuteron and the sum rule integrand for the forward spin polarizability (γ 0 ) near photodisintegration threshold. An analysis of data for the d(γ-vector,n)p reaction and other experiments is presented. A fit to the world data analyzed in this manner gives a GDH integral value of -603±43μb between the photodisintegration threshold and 6 MeV. This result is the first confirmation of the large contribution of the 1 S 0 (M1) transition predicted for the deuteron near photodisintegration threshold. In addition, a sum rule value of 3.75±0.18 fm 4 for γ 0 is obtained between photodisintegration threshold and 6 MeV. This is a first indirect confirmation of the leading-order effective field theory prediction for the forward spin-polarizability of the deuteron

Correlation Matrix Renormalization Theory: Improving Accuracy with Two-Electron Density-Matrix Sum Rules.

Science.gov (United States)

Liu, C; Liu, J; Yao, Y X; Wu, P; Wang, C Z; Ho, K M

2016-10-11

We recently proposed the correlation matrix renormalization (CMR) theory to treat the electronic correlation effects [Phys. Rev. B 2014, 89, 045131 and Sci. Rep. 2015, 5, 13478] in ground state total energy calculations of molecular systems using the Gutzwiller variational wave function (GWF). By adopting a number of approximations, the computational effort of the CMR can be reduced to a level similar to Hartree-Fock calculations. This paper reports our recent progress in minimizing the error originating from some of these approximations. We introduce a novel sum-rule correction to obtain a more accurate description of the intersite electron correlation effects in total energy calculations. Benchmark calculations are performed on a set of molecules to show the reasonable accuracy of the method.

Third family corrections to tri-bimaximal lepton mixing and a new sum rule

International Nuclear Information System (INIS)

Antusch, Stefan; King, Stephen F.; Malinsky, Michal

2009-01-01

We investigate the theoretical stability of the predictions of tri-bimaximal neutrino mixing with respect to third family wave-function corrections. Such third family wave-function corrections can arise from either the canonical normalisation of the kinetic terms or renormalisation group running effects. At leading order both sorts of corrections can be subsumed into a single universal parameter. For hierarchical neutrinos, this leads to a new testable lepton mixing sum rule s=rcosδ+2/3 a (where s,r,a describe the deviations of solar, reactor and atmospheric mixing angles from their tri-bimaximal values, and δ is the observable Dirac CP phase) which is stable under all leading order third family wave-function corrections, as well as Cabibbo-like charged lepton mixing effects

The relation between the photonuclear E1 sum rule and the effective orbital g-factor

Energy Technology Data Exchange (ETDEWEB)

Bentz, Wolfgang E-mail: bentz@keyaki.cc.u-tokai.ac.jp; Arima, Akito

2004-05-17

The connection between the enhancement factor (1+{kappa}) of the photonuclear E1 sum rule and the orbital angular momentum g-factor (g{sub l}) of a bound nucleon is investigated in the framework of the Landau-Migdal theory for isospin asymmetric nuclear matter. Special emphasis is put on the role of gauge invariance to establish the {kappa}-g{sub l} relation. By identifying the physical processes which are taken into account in {kappa} and g{sub l}, the validity and limitations of this relation will be discussed. The connections to the collective excitations and to nuclear Compton scattering are also shown.

Vacuum expectation values of high-dimensional operators and their contributions to the Bjorken and Ellis-Jaffe sum rules

International Nuclear Information System (INIS)

Oganesian, A.G.

1998-01-01

A method is proposed for estimating unknown vacuum expectation values of high-dimensional operators. The method is based on the idea that the factorization hypothesis is self-consistent. Results are obtained for all vacuum expectation values of dimension-7 operators, and some estimates for dimension-10 operators are presented as well. The resulting values are used to compute corrections of higher dimensions to the Bjorken and Ellis-Jaffe sum rules

Playing with QCD I: effective field theories

International Nuclear Information System (INIS)

Fraga, Eduardo S.

2009-01-01

The building blocks of hadrons are quarks and gluons, although color is confined into singlet states. QCD is believed to be the fundamental theory of strong interactions. Its asymptotically free nature puts the vacuum out of reach for perturbation theory. The Lagrangian of QCD and the Feynman rules associated were built by using the Gauge Principle, starting from the quark matter fields and obtaining gluons as connections. A simpler, and sometimes necessary or complementary, approach is provided by effective field theories or effective models, especially when one has to deal with the nonperturbative sector of the theory. (author)

Instanton interpolating current for σ-tetraquark

International Nuclear Information System (INIS)

Lee, Hee-Jung; Kochelev, N.I.

2006-01-01

We perform a QCD sum rule analysis for the light scalar meson σ (f 0 (600)) with a tetraquark current related to the instanton picture for QCD vacuum. We demonstrate that instanton current, including equal weights of scalar and pseudoscalar diquark-antidiquarks, leads to a strong cancelation between the contributions of high dimension operators in the operator product expansion (OPE). Furthermore, in the case of this current direct instanton contributions do not spoil the sum rules. Our calculation, obtained from the OPE up to dimension 10 operators, gives the mass of σ-meson around 780 MeV

Sum rule for bremsstrahlung cross section for 6Li in the resonating-group method

International Nuclear Information System (INIS)

Lodhi, M.A.K.; Wood, K.E.

1982-01-01

In the method of resonating-group structure, the wave function of 6 Li is assumed to have a single channel of alpha and deuteron substructures in the ground state. It is shown that the intercluster exchange of nucleons is an important effect which causes significant change in the root mean square radius and the dipole transition cross section. Due to lack of symmetry in space coordinates of 6 Li, the dipole operator is not identical to the mean square operator for this sum rule calculation and is expected to display like behavior in similar systems. It is also shown that the deuteron substructure in this nucleus is substantially larger than the alpha substructure. (orig.)

Anomaly, mixing and transition form factors of pseudoscalar mesons

International Nuclear Information System (INIS)

Klopot, Yaroslav; Oganesian, Armen; Teryaev, Oleg

2011-01-01

We derive the exact non-perturbative QCD sum rule for the transition form factors of η and η ′ using the dispersive representation of axial anomaly. This sum rule allows to express the transition form factors entirely in terms of meson decay constants. Using this sum rule several mixing schemes were analyzed and compared to recent experimental data. A good agreement with experimental data on η,η ′ transition form factors in the range from real to highly virtual photons was obtained.

QCD condensates in ADS/QCD

DEFF Research Database (Denmark)

Bechi, Jacopo

2009-01-01

This paper focuses on some issues about condensates and renormalization in AdS/QCD models. In particular we consider the consistency of the AdS/QCD approach for scale dependent quantities as the chiral condensate questioned in some recent papers and the 4D meaning of the 5D cosmological constant...... in a model in which the QCD is dual to a 5D gravity theory. We will be able to give some arguments that the cosmological constant is related to the QCD gluon condensate....

Perturbative QCD and exclusive processes

International Nuclear Information System (INIS)

Bennett, J.; Hawes, F.; Zhao, M.; Zyla, P.

1991-01-01

The authors discuss perturbation theory as applied to particle physics calculations. In particle physics one is generally interested in the scattering amplitude for a system going from some initial state to a final state. The intermediate state or states are unknown. To get the scattering amplitude it is necessary to sum the contributions from processes which pass through all possible intermediate states. Intermediate states involve the exchange of intermediate vector bosons between the particles, and with this interaction is associated a coupling constant α. Each additional boson exchange involves an additional contribution of α to the coupling. If α is less than 1, one can see that the relative contribution of higher order processes is less and less important as α falls. In QCD the gluons serve as the intermediate vector bosons exchanged by quarks and gluons, and the interaction constant is not really a constant, but depends upon the distance between the particles. At short distances the coupling is small, and one can assume perturbative expansions may converge rapidly. Exclusive scattering processes, as opposed to inclusive, are those in which all of the final state products are detected. The authors then discuss the application of perturbative QCD to the deuteron. The issues of chiral conservation and color transparancy are also discussed, in the scheme of large Q 2 interations, where perturbative QCD should be applicable

Anomaly, mixing and transition form factors of pseudoscalar mesons

Energy Technology Data Exchange (ETDEWEB)

Klopot, Yaroslav, E-mail: klopot@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation); Oganesian, Armen, E-mail: armen@itep.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation); Institute of Theoretical and Experimental Physics, B. Cheremushkinskaya 25, Moscow 117218 (Russian Federation); Teryaev, Oleg, E-mail: teryaev@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, Joint Institute for Nuclear Research, Joliot-Curie 6, Dubna 141980 (Russian Federation)

2011-10-15

We derive the exact non-perturbative QCD sum rule for the transition form factors of {eta} and {eta}{sup Prime} using the dispersive representation of axial anomaly. This sum rule allows to express the transition form factors entirely in terms of meson decay constants. Using this sum rule several mixing schemes were analyzed and compared to recent experimental data. A good agreement with experimental data on {eta},{eta}{sup Prime} transition form factors in the range from real to highly virtual photons was obtained.

Representation properties, Racah sum rule, and Biedenharn - Elliott identity for Uq(osp(1|2))

International Nuclear Information System (INIS)

Minnaert, P.; Mozrzymas, M.

1998-01-01

It is shown that the universal R matrix in the tensor product of two irreducible representation spaces of the quantum superalgebra U q (osp(1|2)) can be expressed by Clebsch - Gordan coefficients. The Racah sum rule satisfied by U q (osp(1|2)) Racah coefficients and 6-j symbols is derived from the properties of the universal R matrix in the tensor product of three representation spaces. Considering the tensor product of four irreducible representations, it is shown that Biedenharn - Elliott identity holds for U q (osp(1|2)) Racah coefficients and 6-j symbols. A recursion relation for U q (osp(1|2)) 6-j symbols is derived from the Biedenharn endash Elliott identity. copyright 1998 American Institute of Physics

The electric dipole moment of the deuteron from the QCD {theta}-term

Energy Technology Data Exchange (ETDEWEB)

Bsaisou, J.; Liebig, S. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Hanhart, C.; Nogga, A.; Wirzba, A. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich (Germany); Forschungszentrum Juelich, JARA - Forces And Matter Experiments, Juelich (Germany); Meissner, U.G. [Forschungszentrum Juelich, Institut fuer Kernphysik and Juelich Center for Hadron Physics, Juelich (Germany); Forschungszentrum Juelich, Institute for Advanced Simulation, Juelich (Germany); Forschungszentrum Juelich, JARA - Forces And Matter Experiments, Juelich (Germany); Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik, Bonn (Germany); Universitaet Bonn, Bethe Center for Theoretical Physics, Bonn (Germany)

2013-03-15

The two-nucleon contributions to the electric dipole moment (EDM) of the deuteron, induced by the QCD {theta}-term, are calculated in the framework of effective field theory up-to-and-including next-to-next-to-leading order. In particular we find for the difference of the deuteron EDM and the sum of proton and neutron EDM induced by the QCD {theta}-term a value of (- 5.4 {+-}3.9) anti {theta} x 10{sup -} {sup 4} e fm. The by far dominant uncertainty comes from the CP- and isospin-violating {pi}NN coupling constant. (orig.)

Quantum chromodynamics and deep inelastic e - N scattering at TRISTAN

International Nuclear Information System (INIS)

Muta, Taizo

1979-04-01

An introductory survey is given on the formulation of QCD in deep inelastic lepton-hadron scatterings. Typical predictions of QCD are presented in the kinematical region of TRISTAN, including detailed descriptions of the scaling violation, QCD correction to the current algebra sum rules, problem of quark masses and higher order effects. Some suggestions for experiments at TRISTAN are made. (author)

Structural relations of harmonic sums and Mellin transformers at weight w=6

Energy Technology Data Exchange (ETDEWEB)

Bluemlein, Johannes

2009-01-15

We derive the structural relations between nested harmonic sums and the corresponding Mellin transforms of Nielsen integrals and harmonic polylogarithms at weight w=6. They emerge in the calculations of massless single-scale quantities in QED and QCD, such as anomalous dimensions and Wilson coefficients, to 3- and 4-loop order. We consider the set of the multiple harmonic sums at weight six without index {l_brace}-1{r_brace}. This restriction is sufficient for all known physical cases. The structural relations supplement the algebraic relations, due to the shuffle product between harmonic sums, studied earlier. The original amount of 486 possible harmonic sums contributing at weight w=6 reduces to 99 sums with no index {l_brace}-1{r_brace}. Algebraic and structural relations lead to a further reduction to 20 basic functions. These functions supplement the set of 15 basic functions up to weight w=5 derived formerly. We line out an algorithm to obtain the analytic representation of the basic sums in the complex plane. (orig.)

Renormalization of the axial-vector current in QCD

International Nuclear Information System (INIS)

Chiu, C.B.; Pasupathy, J.; Wilson, S.L.

1985-01-01

Following the method of Ioffe and Smilga, the propagation of the baryon current in an external constant axial-vector field is considered. The close similarity of the operator-product expansion with and without an external field is shown to arise from the chiral invariance of gauge interactions in perturbation theory. Several sum rules corresponding to various invariants both for the nucleon and the hyperons are derived. The analysis of the sum rules is carried out by two independent methods, one called the ratio method and the other called the continuum method, paying special attention to the nondiagonal transitions induced by the external field between the ground state and excited states. Up to operators of dimension six, two new external-field-induced vacuum expectation values enter the calculations. Previous work determining these expectation values from PCAC (partial conservation of axial-vector current) are utilized. Our determination from the sum rules of the nucleon axial-vector renormalization constant G/sub A/, as well as the Cabibbo coupling constants in the SU 3 -symmetric limit (m/sub s/ = 0), is in reasonable accord with the experimental values. Uncertainties in the analysis are pointed out. The case of broken flavor SU 3 symmetry is also considered. While in the ratio method, the results are stable for variation of the fiducial interval of the Borel mass parameter over which the left-hand side and the right-hand side of the sum rules are matched, in the continuum method the results are less stable. Another set of sum rules determines the value of the linear combination 7F-5D to be roughly-equal0, or D/(F+D)roughly-equal(7/12). .AE

1-- and 0++ heavy four-quark and molecule states in QCD

International Nuclear Information System (INIS)

Albuquerque, R.M.; Fanomezana, F.; Narison, S.; Rabemananjara, A.

2012-01-01

We estimate the masses of the 1 -- heavy four-quark and molecule states by combining exponential Laplace (LSR) and finite energy (FESR) sum rules known perturbatively to lowest order (LO) in α s but including non-perturbative terms up to the complete dimension-six condensate contributions. This approach allows to fix more precisely the value of the QCD continuum threshold (often taken ad hoc) at which the optimal result is extracted. We use double ratio of sum rules (DRSR) for determining the SU(3) breakings terms. We also study the effects of the heavy quark mass definitions on these LO results. The SU(3) mass-splittings of about (50-110) MeV and the ones of about (250-300) MeV between the lowest ground states and their 1st radial excitations are (almost) heavy-flavor independent. The mass predictions summarized in Table 4 are compared with the ones in the literature (when available) and with the three Y c (4260,4360,4660) and Y b (10890)1 -- experimental candidates. We conclude (to this order approximation) that the lowest observed state cannot be a pure1 -- four-quark nor a pure molecule but may result from their mixings. We extend the above analyzes to the 0 ++ four-quark and molecule states which are about (0.5-1) GeV heavier than the corresponding 1 -- states, while the splittings between the 0 ++ lowest ground state and the 1st radial excitation is about (300-500) MeV. We complete the analysis by estimating the decay constants of the 1 -- and 0 ++ four-quark states which are tiny and which exhibit a 1/M Q behavior. Our predictions can be further tested using some alternative non-perturbative approaches or/and at LHC b and some other hadron factories.

13. international QCD conference (QCD 06)

International Nuclear Information System (INIS)

2006-01-01

This conference was organized around 5 sessions: 1) quantum chromodynamics (QCD) at colliders, 2) CP-violation, Kaon decays and Chiral symmetry, 3) perturbative QCD, 4) physics of light and heavy hadrons, 5) confinement, thermodynamics QCD and axion searches. This document gathers only the slides of the presentations

13. international QCD conference (QCD 06)

Energy Technology Data Exchange (ETDEWEB)

NONE

2006-07-01

This conference was organized around 5 sessions: 1) quantum chromodynamics (QCD) at colliders, 2) CP-violation, Kaon decays and Chiral symmetry, 3) perturbative QCD, 4) physics of light and heavy hadrons, 5) confinement, thermodynamics QCD and axion searches. This document gathers only the slides of the presentations.

Finite volume QCD at fixed topological charge

OpenAIRE

Aoki, Sinya; Fukaya, Hidenori; Hashimoto, Shoji; Onogi, Tetsuya

2007-01-01

In finite volume the partition function of QCD with a given $\\theta$ is a sum of different topological sectors with a weight primarily determined by the topological susceptibility. If a physical observable is evaluated only in a fixed topological sector, the result deviates from the true expectation value by an amount proportional to the inverse space-time volume 1/V. Using the saddle point expansion, we derive formulas to express the correction due to the fixed topological charge in terms of...

The massless limit of supersymmetric QCD

International Nuclear Information System (INIS)

Davis, A.C.; Dine, M.; Seiberg, N.

1983-01-01

We construct an effective lagrangian for supersymmetric QCD, using a simple set of rules. The model with non-zero quark mass, msub(q), has at least N supersymmetric vacua, where N is the number of colors (in agreement with Witten's index). These vacua move to infinity as msub(q)->0. We study the possibility of supersymmetric breaking at msub(q)=0. (orig.)

Fermionic green function and functional determinant in QCD2

International Nuclear Information System (INIS)

Nielsen, N.K.; Rothe, K.D.; Schroer, B.

1979-01-01

We obtain a closed representation for the QCD 2 fermion determinant, euclidean Green functions and induced current in generic external fields. In the absence of zero modes the results are representable as sums over tree diagrams which as we show, can also be obtained from the original Feynman perturbation series via resummation and integration over loop variables. We also investigate the modifications due to the presence of zero modes. (orig.)

Charm quark mass with calibrated uncertainty

Energy Technology Data Exchange (ETDEWEB)

Erler, Jens [Universidad Nacional Autonoma de Mexico, Instituto de Fisica, Mexico, DF (Mexico); Masjuan, Pere [Universitat Autonoma de Barcelona, Grup de Fisica Teorica, Departament de Fisica, Barcelona (Spain); Institut de Fisica d' Altes Energies (IFAE), The Barcelona Institute of Science and Technology (BIST), Barcelona (Spain); Spiesberger, Hubert [Johannes Gutenberg-Universitaet, PRISMA Cluster of Excellence, Institut fuer Physik, Mainz (Germany); University of Cape Town, Centre for Theoretical and Mathematical Physics and Department of Physics, Rondebosch (South Africa)

2017-02-15

We determine the charm quark mass m{sub c} from QCD sum rules of the moments of the vector current correlator calculated in perturbative QCD at O(α{sub s}{sup 3}). Only experimental data for the charm resonances below the continuum threshold are needed in our approach, while the continuum contribution is determined by requiring self-consistency between various sum rules, including the one for the zeroth moment. Existing data from the continuum region can then be used to bound the theoretic uncertainty. Our result is m{sub c}(m{sub c}) = 1272 ± 8 MeV for α{sub s}(M{sub Z}) = 0.1182, where the central value is in very good agreement with other recent determinations based on the relativistic sum rule approach. On the other hand, there is considerably less agreement regarding the theory dominated uncertainty and we pay special attention to the question how to quantify and justify it. (orig.)

Remark on the computation of mode sums

International Nuclear Information System (INIS)

Allen, Theodore J.; Olsson, M. G.; Schmidt, Jeffrey R.

2000-01-01

The computation of mode sums of the types encountered in basic quantum field theoretic applications is addressed with an emphasis on their expansions into functions of distance that can be interpreted as potentials. We show how to regularize and calculate the Casimir energy for the continuum Nambu-Goto string with massive ends as well as for the discrete Isgur-Paton non-relativistic string with massive ends. As an additional example, we examine the effect on the interquark potential of a constant Kalb-Ramond field strength interacting with a QCD string. (c) 2000 The American Physical Society

Non-perturbative studies of QCD at small quark masses

Energy Technology Data Exchange (ETDEWEB)

Wennekers, J.

2006-07-15

We investigate the quenched approximation of lattice QCD with numerical simulations of Ginsparg-Wilson fermions, which are a fermion discretisation with exact chiral symmetry. We compute the renormalisation constant of the scalar density, which allows to extrapolate the chiral condensate to the continuum limit. Furthermore we match lattice results of matrix elements describing hadronic kaon decays to Chiral Perturbation Theory in finite volume and at almost vanishing quark mass. The resulting low-energy constants in the considered SU(4)-flavour symmetric case indicate a substantial contribution of low scale QCD effects to the {delta}I = 1/2 rule. (Orig.)

Finite-width Gaussian sum rules for 0{sup -+} pseudoscalar glueball based on correction from instanton–gluon interference to correlation function

Energy Technology Data Exchange (ETDEWEB)

Wang, Feng; Chen, Junlong; Liu, Jueping, E-mail: jpliu@whu.edu.cn [Department of Physics, School of Physics Science and Technology, Wuhan University, 430072, Wuhan (China)

2015-09-28

Based on a correction from instanton–gluon interference to the correlation function, the properties of the 0{sup -+} pseudoscalar glueball are investigated in a family of finite-width Gaussian sum rules. In the framework of a semiclassical expansion for quantum chromodynamics in the instanton liquid background, the contribution arising from the interference between instantons and the quantum gluon fields is calculated, and it is included in the correlation function together with a pure-classical contribution from instantons and the perturbative one. The interference contribution turns out to be gauge-invariant, to be free from an infrared divergence, and to have a great role to play in restoring the positivity of the spectra of the full correlation function. The negligible contribution from vacuum condensates is excluded in our correlation function to avoid double counting. Instead of the usual zero-width approximation for the resonances, the usual Breit–Wigner form with a suitable threshold behavior for the spectral function of the finite-width resonances is adopted. Consistency between the subtracted and unsubtracted sum rules is very well justified. The values of the mass, decay width, and coupling constants for the 0{sup -+} resonance in which the glueball fraction is dominant are obtained, and they agree with the phenomenological analysis.

Finite-width Gaussian sum rules for 0{sup -+} pseudoscalar glueball based on correction from instanton-gluon interference to correlation function

Energy Technology Data Exchange (ETDEWEB)

Wang, Feng; Chen, Junlong; Liu, Jueping [Wuhan University, Department of Physics, School of Physics Science and Technology, Wuhan (China)

2015-09-15

Based on a correction from instanton-gluon interference to the correlation function, the properties of the 0{sup -+} pseudoscalar glueball are investigated in a family of finite-width Gaussian sum rules. In the framework of a semiclassical expansion for quantum chromodynamics in the instanton liquid background, the contribution arising from the interference between instantons and the quantum gluon fields is calculated, and it is included in the correlation function together with a pure-classical contribution from instantons and the perturbative one. The interference contribution turns out to be gauge-invariant, to be free from an infrared divergence, and to have a great role to play in restoring the positivity of the spectra of the full correlation function. The negligible contribution from vacuum condensates is excluded in our correlation function to avoid double counting. Instead of the usual zero-width approximation for the resonances, the usual Breit-Wigner form with a suitable threshold behavior for the spectral function of the finite-width resonances is adopted. Consistency between the subtracted and unsubtracted sum rules is very well justified. The values of the mass, decay width, and coupling constants for the 0{sup -+} resonance in which the glueball fraction is dominant are obtained, and they agree with the phenomenological analysis. (orig.)

Semileptonic Λb→Λcℓν¯ℓ transition in full QCD

Science.gov (United States)

Azizi, K.; Süngü, J. Y.

2018-04-01

The tree-level b →c ℓν¯ ℓ based hadronic transitions have been the focus of much attention since recording significant deviations of the experimental data, on the ratios of the branching fractions in τ and e -μ channels of the semileptonic B →D transition, from the SM predictions by the BABAR Collaboration in 2012. It can be of great importance to look whether similar discrepancies take place in the semileptonic baryonic Λb→Λcℓν¯ ℓ decay channel or not. In this accordance we estimate the decay width as well as the ratios of the branching fractions in τ and e -μ channels of this baryonic transition by calculating the form factors, entering the amplitude of this transition as the main inputs, in the framework of QCD sum rules in full theory. We compare the obtained results with the predictions of other theoretical studies. Our results may be compared with the corresponding future experimental data to look for possible deviations of data from the SM predictions.

Chimera distribution amplitudes for the pion and the longitudinally polarized ρ-meson

Energy Technology Data Exchange (ETDEWEB)

Stefanis, N.G., E-mail: stefanis@tp2.ruhr-uni-bochum.de [Institut für Theoretische Physik II, Ruhr-Universität Bochum, D-44780 Bochum (Germany); Pimikov, A.V., E-mail: pimikov@theor.jinr.ru [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna (Russian Federation); Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, 730000 (China)

2016-01-15

Using QCD sum rules with nonlocal condensates, we show that the distribution amplitude of the longitudinally polarized ρ-meson may have a shorttailed platykurtic profile in close analogy to our recently proposed platykurtic distribution amplitude for the pion. Such a chimera distribution de facto amalgamates the broad unimodal profile of the distribution amplitude, obtained with a Dyson–Schwinger equations-based computational scheme, with the suppressed tails characterizing the bimodal distribution amplitudes derived from QCD sum rules with nonlocal condensates. We argue that pattern formation, emerging from the collective synchronization of coupled oscillators, can provide a single theoretical scaffolding to study unimodal and bimodal distribution amplitudes of light mesons without recourse to particular computational schemes and the reasons for them.

Light quark masses from exclusive tau decays

International Nuclear Information System (INIS)

Stern, J.; Knecht, M.; Fuchs, N.H.

1993-01-01

A method of indirect measurement of the light quark running mass m-circumflex = (m d + m u )/2 is elaborated in detail. It is based on measuring 1%-level azimuthal angular asymmetries in the decay τ→ν τ + 3π. The latter are then used in QCD sum rules to obtain experimental lower bounds for m-circumflex. For a sample of 2.5 * 10 5 τ→ν τ + 3π decays free of background, the resulting statistical error in the bound for m-circumflex is estimated to be 1 MeV, i.e., comparable to the systematic error due to the use of QCD sum rules. (authors) 22 refs., 7 figs., 1 tab

The extended sum-rule model view of light and intermediate mass fragment emission in nuclear reactions at intermediate energies