14211746
Power counting and effective field theory for charmonium
We hypothesize that the correct power counting for charmonia is in the parameter {Lambda}{sub QCD}/m{sub c}, but is not based purely on dimensional analysis (as is heavy quark effective theory). This power counting leads to predictions which differ from those resulting from the usual velocity power counting rules of non-relativistic QCD (NRQCD). In particular, we show that while {Lambda}{sub QCD}/m{sub c} power counting preserves the empirically verified predictions of spin symmetry in decays, it also leads to new predictions which include a hierarchy between spin singlet and triplet octet matrix elements in the J/{psi} system, a quenching of the net polarization in production at large transverse momentum, and no end point enhancement in radiative decays. We discuss explicit tests which can differentiate between the traditional and new theories of NRQCD.
119001162
Classical Space-Times from the S Matrix
Abstract We show that classical space–times can be derived directly from the S-matrix for a theory of massive particles coupled to a massless spin two particle. As an explicit example we derive the Schwarzchild space–time as a series in G N . At no point of the derivation is any use made of the Einstein–Hilbert action or the Einstein equations. The intermediate steps involve only on-shell S-matrix elements which are generated via BCFW recursion relations and unitarity sewing techniques. The notion of a space–time metric is only introduced at the end of the calculation where it is extracted by matching the potential determined by the S-matrix to the geodesic motion of a test particle. Other static space–times such as Kerr follow in a similar manner. Furthermore, given that the procedure is action independent and depends only upon the choice of the representation of the little group, solutions to Yang–Mills (YM) theory can be generated in the same fashion. Moreover, the squaring relation between the YM and gravity three point functions shows that the seeds that generate solutions in the two theories are algebraically related. From a technical standpoint our methodology can also be utilized to calculate quantities relevant for the binary inspiral problem more efficiently then the more traditional Feynman diagram approach.
14212328
Mother Moose: generating extra dimensions from simple groups at large N
We show that there exists a correspondence between four dimensional gauge theories with simple groups and higher dimensional gauge theories at large N. As an example, we show that a four dimensional $\mathcal{N}=2$ supersymmetric $\mathrm{SU}(N)$ gauge theory, on the Higgs branch, has the same correlators as a five dimensional $\mathrm{SU}(N)$ gauge theory in the limit of large N provided the couplings are appropriately rescaled. We show that our results can be applied to the AdS-CFT correspondence to derive correlators of five or more dimensional gauge theories from solutions of five dimensional supergravity in the large 't Hooft coupling limit.
118962314
Systematics of Coupling Flows in AdS Backgrounds
We give an effective field theory derivation, based on the running of Planck brane gauge correlators, of the large logarithms that arise in the predictions for low energy gauge couplings in compactified AdS}_5 backgrounds, including the one-loop effects of bulk scalars, fermions, and gauge bosons. In contrast to the case of charged scalars coupled to Abelian gauge fields that has been considered previously in the literature, the one-loop corrections are not dominated by a single 4D Kaluza-Klein mode. Nevertheless, in the case of gauge field loops, the amplitudes can be reorganized into a leading logarithmic contribution that is identical to the running in 4D non-Abelian gauge theory, and a term which is not logarithmically enhanced and is analogous to a two-loop effect in 4D. In a warped GUT model broken by the Higgs mechanism in the bulk,we show that the matching scale that appears in the large logarithms induced by the non-Abelian gauge fields is m_{XY}^2/k where m_{XY} is the bulk mass of the XY bosons and k is the AdS curvature. This is in contrast to the UV scale in the logarithmic contributions of scalars, which is simply the bulk mass m. Our results are summarized in a setmore » of simple rules that can be applied to compute the leading logarithmic predictions for coupling constant relations within a given warped GUT model. We present results for both bulk Higgs and boundary breaking of the GUT gauge« less
14142754
The octet structure function and radiative quarkonia decays
The operator product expansion, in conjunction with the power counting of non-relativistic field theory, is used to examine the end-point region of the radiative decay of heavy quark bound states with 3S1 quantum numbers, QQ → γ + X. We identify an infinite class of operators that determine the shape of the photonic end-point spectrum. These operators can be resummed to form an octet structure function which parameterizes the energy of the dynamical gluon content of the leading octet Fock state component of the quarkonium. This color-octet contribution is important when the photon spectrum is examined with a resolution given by ΔEγ ∼ mQν2, where ν is the magnitude of the relative quark velocity. The formalism used makes explicit the shift of the end-point from its partonic to its hadronic value.
54188791
Effective field theory of gravity for extended objects
Using effective field theory (EFT) methods we present a Lagrangian formalism which describes the dynamics of nonrelativistic extended objects coupled to gravity. The formalism is relevant to understanding the gravitational radiation power spectra emitted by binary star systems, an important class of candidate signals for gravitational wave observatories such as LIGO or VIRGO. The EFT allows for a clean separation of the three relevant scales: ${r}_{s}$, the size of the compact objects, $r$, the orbital radius, and $r/v$, the wavelength of the physical radiation (where the velocity $v$ is the expansion parameter). In the EFT, radiation is systematically included in the $v$ expansion without the need to separate integrals into near zones and radiation zones. Using the EFT, we show that the renormalization of ultraviolet divergences which arise at ${v}^{6}$ in post-Newtonian (PN) calculations requires the presence of two nonminimal worldline gravitational couplings linear in the Ricci curvature. However, these operators can be removed by a redefinition of the metric tensor, so that the divergences arising at ${v}^{6}$ have no physically observable effect. Because in the EFT finite size features are encoded in the coefficients of nonminimal couplings, this implies a simple proof of the decoupling of internal structure for spinless objects to at least order ${v}^{6}$. Neglecting absorptive effects, we find that the power counting rules of the EFT indicate that the next set of short distance operators, which are quadratic in the curvature and are associated with tidal deformations, does not play a role until order ${v}^{10}$. These operators, which encapsulate finite size properties of the sources, have coefficients that can be fixed by a matching calculation. By including the most general set of such operators, the EFT allows one to work within a point-particle theory to arbitrary orders in $v$.
55686364
Constraining Extra Neutral Gauge Bosons with Atomic Parity Violation Measurements
The discovery of a new neutral gauge boson, Z ' , could provide the first concrete evidence of physics beyond the standard model. We explore how future parity violation experiments, especially atomic parity violation (APV) experiments, can be used to constrain Zbosons. We use the recent measurement of the 133 Cs nuclear weak charge to estimate lower bounds on the mass of Zbosons for a number of representative models and to put constraints on the couplings of a newly discovered Zboson. We also consider how these constraints might be improved by future APV experiments that will measure nuclear weak charges of multiple isotopes. We show how measurements of a single isotope, and combining measurements into ratios and differences, can be used to constrain the couplings of a Zand discriminate between models. We include in our results the constraints that can be obtained from the experiments Qweak and P2 that measure the proton weak charge. We find that current and future parity violation experiments could potentially play an important role in unravelling new physics if a Zwere discovered.