scholarly journals HOW PENGUINS STARTED TO FLY

1999 ◽  
Vol 14 (30) ◽  
pp. 4705-4719 ◽  
Author(s):  
ARKADY VAINSHTEIN
Keyword(s):  
Cp Violation ◽  
Heavy Quark ◽  
Operator Product Expansion ◽  
Subsequent Development ◽  
Recent Measurement ◽  
Operator Product ◽  
Quark Masses ◽  
Weak Decays ◽  
Particle Phenomenology ◽  
History Of

A mechanism explaining a strong enhancement of nonleptonic weak decays was suggested in 1975, later to be dubbed the penguin. This mechanism extends Wilson's ideas about the operator product expansion at short distances and reveals an intricate interplay of subtle features of the theory such as heavy quark masses in Glashow–Iliopoulos–Maini cancellation, light quarks shaping the chiral properties of QCD, etc. The penguins have subsequently evolved to play a role in a variety of fields in present-day particle phenomenology. I will describe the history of this idea and review its subsequent development. The recent measurement of direct CP violation in K decays gives a new confirmation of the penguin mechanism.

scholarly journals NEW INSIGHTS CONCERNING DIMENSION EIGHT EFFECTS IN WEAK DECAYS

2001 ◽  
Vol 16 (supp01c) ◽  
pp. 1228-1230
Author(s):  
JOHN F. DONOGHUE
Keyword(s):  
Operator Product Expansion ◽  
Short Distance ◽  
Numerical Estimate ◽  
Dimensional Regularization ◽  
Operator Product ◽  
Higher Dimension ◽  
Matrix Elements ◽  
Weak Decays ◽  
The Matrix ◽  
Weak Operator

Most past work on weak nonleptonic decays has mixed dimensional regularization in the weak operator product expansion with some form of a cutoff regularization in the evaluation of the matrix elements. Even with the usual technique of matching the two schemes, this combination misses physics at short distance which can be described by dimension eight (and higher dimension) operators. I describe some recent work with V. Cirigliano and E. Golowich which clarifies these effects and provides a numerical estimate suggesting that they are important.

Effective Field Theories for Heavy Quarks: Heavy Quark Effective Theory and Heavy Quark Expansion

2020 ◽  
pp. 560-615
Author(s):  
Thomas Mannel
Keyword(s):  
Heavy Quark ◽  
Particle Physics ◽  
Operator Product Expansion ◽  
Effective Field ◽  
Field Theories ◽  
Effective Theory ◽  
Tree Level ◽  
Operator Product ◽  
Heavy Quark Effective Theory ◽  
Inclusive Decays

The heavy quark effective theory (HQET) and the heavy quark expansion (HQE) have developed into the standard tools in heavy-flavour physics. The lectures in this chapter introduce the basics of the approach and illustrates the methods by discussing some of their phenomenological applications. The chapter covers construction of the HQET Lagrangian, symmetries of HQET, HQET at one loop, and HQET applications to phenomenology. It also discusses HQE inclusive decays, operator product expansion (OPE), tree-level results, HQE parameters, QCD corrections, and end-point regions. It concludes by reiterating the enormous impact that both HQET and the HQE have had on particle physics phenomenology.

scholarly journals Parton physics from a heavy-quark operator product expansion: Formalism and Wilson coefficients

2021 ◽  
Vol 104 (7) ◽  
Author(s):  
William Detmold ◽  
Anthony V. Grebe ◽  
Issaku Kanamori ◽  
C.-J. David Lin ◽  
Robert J. Perry ◽  
...  
Keyword(s):  
Heavy Quark ◽  
Operator Product Expansion ◽  
Operator Product ◽  
Quark Operator

scholarly journals NON-FACTORIZABLE TERMS, HEAVY QUARK MASSES, AND SEMILEPTONIC DECAYS OF D AND B MESONS

2002 ◽  
Vol 17 (04) ◽  
pp. 245-251 ◽  
Author(s):  
M. B. VOLOSHIN
Keyword(s):  
Heavy Quark ◽  
B Mesons ◽  
D Mesons ◽  
Semileptonic Decay ◽  
Semileptonic Decays ◽  
Operator Product ◽  
B Decays ◽  
Quark Masses ◽  
Mixing Parameter

The non-factorizable terms in the operator product expansion have been recognized as one of the theoretical obstacles for precision determination of the mixing parameter Vub from semileptonic B decays. It is pointed out here that the recent CLEO data on the parameters of the heavy quark expansion λ1 and [Formula: see text], combined with a theoretical bound on λ1 strongly favor the existence of a sizeable contribution of non-factorizable terms in semileptonic decays of D mesons. Thus these terms are likely to solve the long-standing problem of the deficit of semileptonic decay rate of the D mesons, and with better data their magnitude can be determined and used in studies of the parameter Vub.

THE OPERATOR PRODUCT EXPANSION OF THE QCD PROPAGATORS

1992 ◽  
Vol 07 (39) ◽  
pp. 3617-3630 ◽  
Author(s):  
MARTIN LAVELLE ◽  
MICHAEL OLESZCZUK
Keyword(s):  
Operator Product Expansion ◽  
Arbitrary Dimension ◽  
Light Quark ◽  
Equations Of Motion ◽  
Internal Symmetry ◽  
Operator Product ◽  
General Belief ◽  
Quark Masses ◽  
Acceleration Technique ◽  
The Status

We bring together for the first time the coefficients in covariant gauges of all the condensates of dimension four or less in the operator product expansion (OPE) of the quark, gluon and ghost propagators. It is stressed that contrary to general belief the condensates do not enter the OPE of the propagators in gauge-invariant combinations like [Formula: see text] and 〈G2〉. The results are presented in arbitrary dimension to lowest order in the light quark masses for the SU (Nc) internal symmetry group. All terms which, through the equations of motion, may be viewed as being effectively of order αs are included. The importance of the equations of motion if one is to fulfill the Slavnov-Taylor identities is demonstrated. We briefly consider the equivalent, but less complete, calculations in other gauges and give an overview of the status of the OPE of the QCD vertices. Finally we discuss what these non-perturbative structures tell us about the correct solutions of QCD and point out their significance for the Fourier acceleration technique as applied to lattice QCD.

scholarly journals Implications of tau data for CP violation in K decays

2019 ◽  
Author(s):  
Antonio Rodríguez Sánchez
Keyword(s):  
Cp Violation ◽  
Operator Product Expansion ◽  
Short Distance ◽  
Chiral Limit ◽  
Operator Product ◽  
Distance Constraint ◽  
Matrix Elements ◽  
Kaon Decays ◽  
The Matrix

The \bm{D=6}𝐃=6 contribution of the Operator Product Expansion (OPE) of the \bm{\mathrm{VV-AA}}VV−AA correlator of quark currents can be related to hadronic matrix elements associated to CP violation in non-leptonic kaon decays. We use those relations to find an updated value for \bm{\langle(\pi\pi)_{I=2}|\mathcal{Q}_{8}|K\rangle}⟨(𝛑𝛑)𝐈=2|𝒬8|𝐊⟩ in the chiral limit using the updated ALEPH spectral function. Taking instead values of the matrix elements from the lattice to obtain the \bm{D=6}𝐃=6 vacuum elements provides a new short-distance constraint that allows for an inclusive determination of \bm{f_{\pi}}𝐟𝛑 and an updated value for the \bm{D=8}𝐃=8 condensate.

scholarly journals A Narrative Review of the History of Skin Grafting in Burn Care

Medicina ◽  
2021 ◽  
Vol 57 (4) ◽  
pp. 380
Author(s):  
Deepak K. Ozhathil ◽  
Michael W. Tay ◽  
Steven E. Wolf ◽  
Ludwik K. Branski
Keyword(s):  
Donor Site ◽  
Subsequent Development ◽  
Skin Grafting ◽  
Human Condition ◽  
Surgical Instruments ◽  
Wound Management ◽  
Burn Wound ◽  
Medical Progress ◽  
Burn Care ◽  
History Of

Thermal injuries have been a phenomenon intertwined with the human condition since the dawn of our species. Autologous skin translocation, also known as skin grafting, has played an important role in burn wound management and has a rich history of its own. In fact, some of the oldest known medical texts describe ancient methods of skin translocation. In this article, we examine how skin grafting has evolved from its origins of necessity in the ancient world to the well-calibrated tool utilized in modern medicine. The popularity of skin grafting has ebbed and flowed multiple times throughout history, often suppressed for cultural, religious, pseudo-scientific, or anecdotal reasons. It was not until the 1800s, that skin grafting was widely accepted as a safe and effective treatment for wound management, and shortly thereafter for burn injuries. In the nineteenth and twentieth centuries skin grafting advanced considerably, accelerated by exponential medical progress and the occurrence of man-made disasters and global warfare. The introduction of surgical instruments specifically designed for skin grafting gave surgeons more control over the depth and consistency of harvested tissues, vastly improving outcomes. The invention of powered surgical instruments, such as the electric dermatome, reduced technical barriers for many surgeons, allowing the practice of skin grafting to be extended ubiquitously from a small group of technically gifted reconstructive surgeons to nearly all interested sub-specialists. The subsequent development of biologic and synthetic skin substitutes have been spurred onward by the clinical challenges unique to burn care: recurrent graft failure, microbial wound colonization, and limited donor site availability. These improvements have laid the framework for more advanced forms of tissue engineering including micrografts, cultured skin grafts, aerosolized skin cell application, and stem-cell impregnated dermal matrices. In this article, we will explore the convoluted journey that modern skin grafting has taken and potential future directions the procedure may yet go.

Sign in / Sign up

Export Citation Format

Share Document