ABC of instantons

Vainshtein, A.I.; Захаров, В. И.; Novikov, V.A.; Shifman, M.

doi:10.1070/pu1982v025n04abeh004533

Cited by 338 publications

(358 citation statements)

References 2 publications

Supporting

Mentioning

348

Contrasting

Unclassified

Order By: Relevance

“…The first leading log calculations of η 1 have been presented in (Vainshtein et al, 1976), (Novikov et al, 1977) and of η 2 in (Vysotskij, 1980). The complete leading log calculation inlcuding also η 3 has been first performed in (Gilman and Wise, 1983).…”

Section: The Effective Hamiltonian Formentioning

confidence: 99%

Weak decays beyond leading logarithms

1996

View full text Add to dashboard Cite

arXiv:hep-ph/9512380v1 15 Dec 1995 M P I − P h/95 − 104 T U M − T 31 − 100/95 F ERM ILAB − P U B − 95/305 − T SLAC − P U B 7009 November 1995) to appear in Reviews of Modern Physics WEAK DECAYS BEYOND LEADING LOGARITHMS AbstractWe review the present status of QCD corrections to weak decays beyond the leading logarithmic approximation including particle-antiparticle mixing and rare and CP violating decays. After presenting the basic formalism for these calculations we discuss in detail the effective hamiltonians for all decays for which the next-to-leading corrections are known. Subsequently, we present the phenomenological implications of these calculations. In particular we update the values of various parameters and we incorporate new information on m t in view of the recent top quark discovery. One of the central issues in our review are the theoretical uncertainties related to renormalization scale ambiguities which are substantially reduced by including next-to-leading order corrections. The impact of this theoretical improvement on the determination of the Cabibbo-Kobayashi-Maskawa matrix is then illustrated in various cases. *

show abstract

Section: The Effective Hamiltonian Formentioning

confidence: 99%

Weak decays beyond leading logarithms

1996

View full text Add to dashboard Cite

show abstract

“…The two-gluon interaction with quark induced by instanton follows from the generalized t'Hooft Lagrangian obtained from quark and gluon fields in instanton background [5,37,3,4]:…”

Section: Proton Spin Problem and Glueball X(1835)mentioning

confidence: 99%

X(1835) as the lowest mass pseudoscalar glueball and proton spin problem

Kochelev

Min

2006

Physics Letters B

View full text Add to dashboard Cite

We consider the parity doublet structure observed in high hadronic excitations within the instanton model for the QCD vacuum. In the conventional approach this doubling phenomenon is treated as a manifestation of the partial restoration of chiral or U (1) A symmetry. We demonstrate that the suppression of direct instanton contribution to the masses of excited hadrons leads to the partial U(1) A symmetry restoration in hadron spectrum. The origin of X(1835) resonance observed by BES Collaboration is studied upon the doublet structure. We argue also how X(1835) be interpreted as the lowest pseudoscalar glueball state, and derive its coupling constant to proton. It turns out that this coupling is large and negative. Demonstrated is how this large coupling affects the gluonic contribution to the proton spin.

show abstract

“…For the harmonic oscillator, the potential ∂ 2 V (x)/∂x 2 | x=x flucton in (15) is just a constant, so in this case the fluctuations do not depend on the classical path, and direct diagonalization of the operator (15) [5] shows that…”

Section: Relating the Determinant And The Green Functionmentioning

confidence: 99%

Fluctuations in quantum mechanics and field theories from a new version of semiclassical theory. II.

2017

View full text Add to dashboard Cite

This is the second paper on semiclassical approach based on the density matrix given by the Euclidean time path integral with fixed coinciding endpoints. The classical path, interpolating between this point and the classical vacuum, called "flucton", plus systematic one-and two-loop corrections, has been calculated in the first paper [1] for double-well potential and now extended for a number of quantum-mechanical problems (anharmonic oscillator, sine-Gordon potential). The method is based on systematic expansion in Feynman diagrams and thus can be extended to QFTs. We show that the loop expansion in QM reminds the leading log-approximations in QFT. In this sequel we present complete set of results obtained using this method in unified way. Alternatively, starting from the Schrödinger equation we derive a generalized Bloch equation which semiclassicallike, iterative solution generates the loop expansion. We re-derive two loop expansions for all three above potentials and now extend it to three loops, which has not yet been done via Feynman diagrams. All results for both methods are fully consistent with each other. Asymmetric (tilted) double-well potential (non-degenerate minima) is also studied using the second method.

show abstract

ABC of instantons

Cited by 338 publications

References 2 publications

Weak decays beyond leading logarithms

Weak decays beyond leading logarithms

X(1835) as the lowest mass pseudoscalar glueball and proton spin problem

Fluctuations in quantum mechanics and field theories from a new version of semiclassical theory. II.

Contact Info

Product

Resources

About