The primary experimental goal of studies of hadronic parity nonconservation (PNC) has long been the isolation of the isovector weak nucleon-nucleon interaction, expected to be dominated by long-range ...pion exchange and enhanced by the neutral current. In meson-exchange descriptions, this interaction, together with an isoscalar interaction generated by
and
exchange, dominates most observables. Both amplitudes have been used to compare and check the consistency of experiments, yet no evidence for isovector hadronic PNC has been found. We argue that the emphasis on isovector hadronic PNC was misplaced. The large-
expansion provides an alternative and theoretically better-motivated simplification of effective field theories (EFTs) of hadronic PNC, separating the five low-energy constants (LECs) into two of leading order (LO) and three of next-to-next-to-leading order (N
LO). We show that this large-
LEC hierarchy accurately describes all existing data on hadronic PNC and discuss opportunities to further test the predicted large-
LEC hierarchy. This formalism-combined with future experiments-could lead to rapid progress in the next 5 years. We discuss the impact of anticipated new results and describe future experiments that can yield more precise values of the LO LECs and help to isolate the N
LO
10% corrections.
Light-like scattering in quantum gravity Bjerrum-Bohr, N. E. J.; Donoghue, John F.; Holstein, Barry R. ...
The journal of high energy physics,
11/2016, Volume:
2016, Issue:
11
Journal Article
Peer reviewed
Open access
A
bstract
We consider scattering in quantum gravity and derive long-range classical and quantum contributions to the scattering of light-like bosons and fermions (spin-0, spin-
1
2
, spin-1) from an ...external massive scalar field, such as the Sun or a black hole. This is achieved by treating general relativity as an effective field theory and identifying the non-analytic pieces of the one-loop gravitational scattering amplitude. It is emphasized throughout the paper how modern amplitude techniques, involving spinor-helicity variables, unitarity, and squaring relations in gravity enable much simplified computations. We directly verify, as predicted by general relativity, that all classical effects in our computation are universal (in the context of matter type and statistics). Using an eikonal procedure we confirm the post-Newtonian general relativity correction for light-like bending around large stellar objects. We also comment on treating effects from quantum ℏ dependent terms using the same eikonal method.
Describing the fundamental theory of particle physics and its applications, this book provides a detailed account of the Standard Model, focusing on techniques that can produce information about real ...observed phenomena. It begins with a pedagogic account of the Standard Model, introducing essential techniques such as effective field theory and path integral methods. It then focuses on the use of the Standard Model in the calculation of physical properties of particles. Rigorous methods are emphasized, but other useful models are also described. The second edition has been updated to include theoretical and experimental advances, such as the discovery of the Higgs boson, our understanding of neutrinos, and the major advances in CP violation and electroweak physics. This book is valuable to graduate students and researchers in particle physics, nuclear physics and related fields. This edition, first published in 2014, has been reissued as an Open Access publication on Cambridge Core.
Hadron Polarizabilities Holstein, Barry R; Scherer, Stefan
Annual review of nuclear and particle science,
10/2014, Volume:
64, Issue:
1
Journal Article
Peer reviewed
Open access
Electromagnetic polarizabilities describe the response of a system to the application of an external quasi-static electric or magnetic field. In this article, we examine experimental and theoretical ...work addressing the polarizabilities of the light hadrons.
Bending of light in quantum gravity Bjerrum-Bohr, N E J; Donoghue, John F; Holstein, Barry R ...
Physical review letters,
2015-Feb-13, Volume:
114, Issue:
6
Journal Article
Peer reviewed
Open access
We consider the scattering of lightlike matter in the presence of a heavy scalar object (such as the Sun or a Schwarzschild black hole). By treating general relativity as an effective field theory we ...directly compute the nonanalytic components of the one-loop gravitational amplitude for the scattering of massless scalars or photons from an external massive scalar field. These results allow a semiclassical computation of the bending angle for light rays grazing the Sun, including long-range ℏ contributions. We discuss implications of this computation, in particular, the violation of some classical formulations of the equivalence principle.
Classical physics and quantum loops HOLSTEIN, Barry R; DONOGHUE, John F
Physical review letters,
11/2004, Volume:
93, Issue:
20
Journal Article
Peer reviewed
The standard picture of the loop expansion associates a factor of variant Planck's over 2pi with each loop, suggesting that the tree diagrams are to be associated with classical physics, while loop ...effects are quantum mechanical in nature. We discuss counterexamples wherein classical effects arise from loop diagrams and display the relationship between the classical terms and the long range effects of massless particles.
The study of Compton scattering—S + γ → S + γ—at MAMI and elsewhere has led to a relatively successful understanding of proton structure via its polarizabilities. The recent observation of ...gravitational radiation observed by LIGO has raised the need for a parallel understanding of gravitational Compton scattering—S + g → S + g—and we show here how it can be obtained from ordinary Compton scattering by use of the double copy theorem.
We consider the role of precision measurements of beta decays and light meson semi-leptonic decays in probing physics beyond the Standard Model in the LHC era. We describe all low-energy ...charged-current processes within and beyond the Standard Model using an effective field theory framework. We first discuss the theoretical hadronic input which in these precision tests plays a crucial role in setting the baseline for new physics searches. We then review the current and upcoming constraints on the various non-standard operators from the study of decay rates, spectra, and correlations in a broad array of light-quark systems. We finally discuss the interplay with LHC searches, both within models and in an effective theory approach. Our discussion illustrates the independent yet complementary nature of precision beta decay measurements as probes of new physics, showing them to be of continuing importance throughout the LHC era.
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