arXiv subjects

Andrew G. Cohen

Publications and source records attributed to Andrew G. Cohen.

24 records · Page 2Linked to original sources

arXiv1999

Solving the Hierarchy Problem with Noncompact Extra Dimensions

We show that gravitational effects of global cosmic 3-branes can be responsible for compactification from six to four space-time dimensions, naturally producing the observed hierarchy between electroweak and gravitational forces. The finite radius of the transverse dimensions follows from Einstein's equation, and is exponentially large compared with the scales associated with the 3-brane. The space-time ends on a mild naked singularity at the boundary of the transverse dimensions; nevertheless unitary boundary conditions render the singularity harmless.

hep-th↗

arXiv1999

Effective Field Theory, Black Holes, and the Cosmological Constant

Bekenstein has proposed the bound S < pi M_P^2 L^2 on the total entropy S in a volume L^3. This non-extensive scaling suggests that quantum field theory breaks down in large volume. To reconcile this breakdown with the success of local quantum field theory in describing observed particle phenomenology, we propose a relationship between UV and IR cutoffs such that an effective field theory should be a good description of Nature. We discuss implications for the cosmological constant problem. We find a limitation on the accuracy which can be achieved by conventional effective field theory: for example, the minimal correction to (g-2) for the electron from the constrained IR and UV cutoffs is larger than the contribution from the top quark.

hep-th↗

arXiv1999

A New Constraint on Strongly Coupled Field Theories

We propose a new constraint on the structure of strongly coupled field theories. The constraint takes the form of an inequality limiting the number of degrees of freedom in the infrared description of a theory relative to the number of underlying, ultraviolet degrees of freedom. We apply the inequality to a variety of theories (both supersymmetric and nonsupersymmetric), where it agrees with all known results and leads to interesting new constraints on low energy spectra. We discuss the relation of this constraint to Renormalization Group c-theorems.

hep-th↗

arXiv1997

Counting 4 pi 's in Strongly Coupled Supersymmetry

We extend the "naive dimensional analysis" arguments used in QCD for estimating the strengths of operators in chiral Lagrangians to strongly coupled supersymmetric theories. In particular, we show how to count factors of 4 pi ---an inexact science, but nevertheless a useful art when such theories are used to model real particle physics.

hep-ph↗

arXiv1997

B-factory Physics from Effective Supersymmetry

We discuss how to extract non-Standard Model effects from B-factory phenomenology. We then analyze the prospects for uncovering evidence for Effective Supersymmetry, a class of supersymmetric models which naturally suppress flavor changing neutral currents and electric dipole moments without squark universality or small CP violating phases, in experiments at BaBar, BELLE, HERA-B, CDF/D0 and LHC-B.

hep-ph↗

arXiv1992

A Comment on the Strong Interactions of Color-Neutral Technibaryons

We estimate the cross section for the scattering of a slow, color-neutral technibaryon made of colored constituents with nuclei. We find a cross section of order $A^2\ 10^{-45}$ cm$^2$, where $A$ is the atomic number of the nucleus. Even if technibaryons constitute the dark matter in the galactic halo, this is too small to be detected in future underground detectors.

hep-ph↗