118465032
Integration-by-parts identities from the viewpoint of differential geometry
We present a new method to construct integration-by-part (IBP) identities from the viewpoint of differential geometry. Vectors for generating IBP identities are reformulated as differential forms, via Poincar\'{e} duality. Using the tools of differential geometry and commutative algebra, we can efficiently find differential forms which generate on-shell IBP relation without doubled propagator. Various $D=4$ two-loop examples are presented.
118592385
The complete KLT-map between gravity and gauge theories
A bstractWe present the complete map of any pair of super Yang-Mills theories to supergravity theories as dictated by the KLT relations in four dimensions. Symmetries and the full set of associated vanishing identities are derived. A graphical method is introduced which simplifies counting of states, and helps in identifying the relevant set of symmetries.
117774008
Remarks on the Identities of Gluon Tree Amplitudes
Recently, Bjerrum-Bohr, Damgaard, Feng, and Sondergaard derived a set of new interesting quadratic identities of the Yang-Mills (YM) tree scattering amplitudes, besides Bern-Carrasco-Johansson (BCJ) identities. Here we comment that these quadratic identities of YM amplitudes actually follow directly from the KLT (Kawai-Lewellen-Tye) relation for graviton-dilaton-axion scattering amplitudes (in four-dimensional spacetime). This clarifies their physical origin and also provides a simpler version of the new identities. We also comment that the recently discovered BCJ identities of YM helicity amplitudes, at least for the maximal helicity-violating case, can be verified by using (repeatedly) the Schouten identity. We also point out additional quadratic identities that can be written down from the KLT relations.
119221055
An integrand reconstruction method for three-loop amplitudes
A bstractWe consider the maximal cut of a three-loop four point function with massless kinematics. By applying Gröbner bases and primary decomposition we develop a method which extracts all ten propagator master integral coefficients for an arbitrary triple-box configuration via generalized unitarity cuts. As an example we present analytic results for the three loop triple-box contribution to gluon-gluon scattering in Yang-Mills with adjoint fermions and scalars in terms of three master integrals.
657952
Coleman-De Luccia Tunneling and The Gibbons-Hawking Temperature
We study Coleman–de Luccia tunneling in some detail. We show that, for a single scalar field potential with a true and a false vacuum, there are four types of tunneling, depending on the properties of the potential. A general tunneling process involves a combination of thermal (Gibbons–Hawking temperature) fluctuation part way up the barrier followed by quantum tunneling. The thin-wall approximation is a special limit of the case (of only quantum tunneling) where inside the nucleation bubble is the true vacuum while the outside reaches the false vacuum. Hawking–Moss tunneling is the (only thermal fluctuation) limit of the case where the inside of the bubble does not reach the true vacuum at the moment of its creation, and the outside is cut off by the de Sitter horizon before it reaches the false vacuum. A typical tunneling process is a combination of thermal and quantum tunnelings. We estimate the tunneling rate for this case and find that the corrections to the Hawking–Moss formula can be large. In all cases, we see that the Euclidean action of the bounce decreases rapidly as the vacuum energy density increases, signaling that the tunneling is not exponentially suppressed. This phenomenon may be interpreted as a finite temperature effect due to the Gibbons–Hawking temperature of the de Sitter space. As an application, we discuss the implication of this tunneling property to the cosmic landscape.
118419441
Multi-loop integrand reduction techniques
We review recent progress in D-dimensional integrand reduction algorithms for two loop amplitudes and give examples of their application to non-planar maximal cuts of the five-point all-plus helicity amplitude in QCD.
5717442
On the Construction of Trigonometric Solutions of the Yang-Baxter Equation
We describe the construction of trigonometric R-matrices corresponding to the (multiplicity-free) tensor product of two irreducible representations of a quantum algebra Uq(G). Our method is a generalization of the tensor product graph method to the case of two different representations. It yields the decomposition of the R-matrix into projection operators. Many new examples of trigonometric R-matrices (solutions to the spectral parameter dependent Yang-Baxter equation) are constructed using this approach.
120019613
Cohomology in connection space, family index theorem, and Abelian gauge structure
Using the natural connection form on a principal bundle P(M,G) and the bundle A (A /G,G) a systematic derivation of the double‐cohomological series constituted by the exterior differential d on space‐time M and arbitrary, horizontal, and vertical variations in connection space is given. The relationship between these cohomologies and the family index theorem is clarified. The formalism is then used to analyze Abelian gauge structure inside non‐Abelian gauge theory. The pertinent functional U(1) connection form, curvature form, and three‐form ‘‘curvature’’ are identified and computed, and are related to the θ vacuum, anomalous commutation relation, and Jacobi identity, respectively. Some of the results differ from those obtained by Wu and Zee [Nucl. Phys. B 258, 157 (1985)] and Niemi and Semenoff [Phys. Rev. Lett. 55, 227 (1985)] and the results of this paperrecover theirs under certain conditions. Finally the generalization of the formalism to a nontrivial principal bundle by introduction of a fixed backg...
14566329
Eigenvalues of Casimir invariants for type I quantum superalgebras
We present the eigenvalues of the Casimir invariants for the type I quantum superalgebras on any irreducible highest weight module.
119494793
$\Upsilon$ radiative decays to light quark jets and color octet mechanism
We study radiative decays of $\Upsilon$ to light quark jets in nonrelativistic QCD by taking both the color singlet and color octet $b\bar b$ operators into consideration. The cut for quark jet energy and cut for the angle between two quark jets are introduced. The sensitivity to the soft and collinear singularities in the loop integrals are greatly reduced by these cuts. With the jet energy cut of about 1 GeV, and the jet angle cut of about $36^\circ$, the branching ratio for $\Upsilon\to\gamma q\bar q$ is found to be $8.2\times 10^{-4}$ from color singlet contributions. The color octet contributions could be much larger than that of color singlet, depending on the estimate of the color octet matrix elements. This process may provide a new test for the color octet mechanism in nonrelativistic QCD.
13608539
Integrable four-Fermi models with a boundary and boson-fermion duality
Construction of integrable field theories in space with a boundary is extended to fermionic models. We obtain general forms of boundary interactions consistent with integrability of the massive Thirring model and study the duality equivalence of the MT model and the sine-Gordon model with boundary terms. We find a variety of integrable boundary interactions in the O(3) Gross-Neveu model from the boundary supersymmetric sine-Gordon theory by using boson-fermion duality.