Journal of High Energy Physics最新文献

We introduce a new class of non-compact backgrounds of Type IIB string theory preserving eight supercharges by combining S-folds and non-perturbative 7-branes wrapping orbifolds, and study the four-dimensional superconformal field theories arising at low energy on D3-branes probing them. We draw a precise correspondence between this setup and the torus compactification of six-dimensional orbi-instanton theories with a Stiefel-Whitney twist, and use it to determine the main features of such strongly-coupled systems, like central charges, spectra of Coulomb-branch operators, networks of Higgs-branch flows. Finally, with the aim to improve our understanding of the landscape of ( mathcal{N} ) = 2 superconformal field theories, and possibly to extend their classification beyond rank two, we provide a detailed catalogue of all the rank-three theories that our framework gives access to.

We interpret infinite-distance limits in the complex structure moduli space of F-theory compactifications to six dimensions in the light of general ideas in quantum gravity. The limits we focus on arise from non-minimal singularities in the elliptic fiber over curves in a Hirzebruch surface base, which do not admit a crepant resolution. Such degenerations take place along infinite directions in the non-perturbative brane moduli space in F-theory. A blow-up procedure, detailed generally in Part I of this project [1], gives rise to an internal space consisting of a union of log Calabi-Yau threefolds glued together along their boundaries. We geometrically classify the resulting configurations for genus-zero single infinite-distance limits. Special emphasis is put on the structure of singular fibers in codimension zero and one. As our main result, we interpret the central fiber of these degenerations as endpoints of a decompactification limit with six-dimensional defects. The conclusions rely on an adiabatic limit to gain information on the asymptotically massless states from the structure of vanishing cycles. We also compare our analysis to the heterotic dual description where available. Our findings are in agreement with general expectations from quantum gravity and provide further evidence for the Emergent String Conjecture.

We develop a comprehensive framework for extracting the pole position and properties of the doubly-charmed tetraquark ( {T}_{textrm{cc}}^{+}(3875) ) from lattice QCD data using the relativistic three-particle formalism. This approach incorporates the effect of the one-pion exchange diagram in DDπ and DD^∗ scattering, making it applicable at energies coinciding with the left-hand cut in the partial-wave projected DD^∗ amplitude. We present an example application of this framework to existing lattice QCD data at m_π = 280 MeV. We solve the integral equations describing the DDπ reaction, use LSZ reduction to determine the corresponding DD^∗ amplitude, and find the values of the infinite-volume two- and three-body K matrices that lead to agreement with lattice DD^∗ phase shifts within their uncertainties. Using these K matrices in the three-particle quantization condition, we describe the finite- volume DD^∗ spectrum and find good agreement with the lattice QCD energies. Our results suggest that, at this pion mass, the tetraquark appears as a pair of subthreshold complex poles whose precise location strongly depends on the value of the DDπ three-particle K matrix.

We present a flavour non-universal extension of the Standard Model combined with the idea of Higgs compositeness. At the TeV scale, the gauge groups SU(2)_R and U(1)_B−L are assumed to act in a non-universal manner on light- and third-generation fermions, while the Higgs emerges as a pseudo Nambu-Goldstone boson of the spontaneous global symmetry breaking Sp(4) → SU(2)_L × ( textrm{SU}{(2)}_R^{left[3right]} ), attributed to new strong dynamics. The flavour deconstruction means the couplings of the light families to the composite sector (and therefore the pNGB Higgs) are suppressed by powers of a heavy mass scale (from which the Higgs is nevertheless shielded by compositeness), explaining the flavour puzzle. We present a detailed analysis of the radiatively generated Higgs potential, showing how this intrinsically-flavoured framework has the ingredients to justify the unavoidable tuning in the Higgs potential necessary to separate electroweak and composite scales. This happens for large enough values of the ( textrm{SU}{(2)}_R^{left[3right]} ) gauge coupling and light enough flavoured gauge bosons resulting from the deconstruction, whose phenomenology is also investigated. The model is compatible with current experimental bounds and predicts new states at the TeV scale, which are within the reach of near future experimental searches.

Charges associated with gauge symmetries are defined on boundaries of spacetimes. But these constructions typically involve divergent quantities when considering asymptotic boundaries. Different prescriptions exist to address this problem, based on ambiguities in the definition of the symplectic potential. We propose a method well suited to leaky boundaries, which describe spacetimes than can exchange matter or radiation with their environment. The main advantage of this approach is that it relies only on the bulk Lagrangian and it is not tied to a specific choice of boundary conditions. The prescription is applied to four dimensional Einstein-Hilbert gravity in the partial Bondi gauge. This leads to a finite symplectic potential for unconstrained boundary data and reveals two new corner symplectic pairs associated with the relaxation of the gauge.

In their seminal work, Lellouch and Lüscher derived a conversion factor relating a finite-volume matrix element, calculable using numerical lattice QCD, with the infinite-volume decay amplitude for K → ππ. The conversion factor depends on the ππ → ππ scattering amplitude with the same total isospin as the decay channel (either zero or two). Although an infinite tower of ππ → ππ partial-wave components affect the conversion factor, the S-wave (ℓ = 0) component is expected to dominate, and only this contribution is included in the well-known Lellouch-Lüscher factor, with other ππ → ππ partial-wave amplitudes formally set to zero. However, as the precision of lattice calculations increases, it may become important to assess the systematic uncertainty arising from this approximation. With this motivation, we compare the S-wave-only results with those truncated at the next contaminating partial wave: the G-wave (ℓ = 4) for zero total momentum in the finite-volume frame and the D-wave (ℓ = 2) otherwise. Using the general framework for ( 1overset{mathcal{J}}{to }2 ) transitions derived in ref. [1], we quantify the effect of higher partial waves for systems with zero and non-zero total momentum as well as with anti-periodic boundary conditions, presenting both generic numerical examples and results for realistic ππ amplitudes taken from chiral perturbation theory and dispersive analysis. We also consider the accidental degeneracy occurring in the 8^th excited state of the zero-momentum system. This exhibits qualitatively new features at ℓ = 4, not seen in the ℓ = 0 truncation.

We study correlation functions of spectrally-flowed vertex operators in bosonic string theory on AdS₃ × 𝑋 in the path integral formalism. By restricting the path integral to only include worldsheets which live near the asymptotic boundary, we compute correlation functions of spectrally-flowed vertex operators and find a precise agreement with the perturbative correlators in the recently-proposed dual CFT at all orders in conformal perturbation theory. We thus provide highly nontrivial evidence for the bulk/boundary duality.

We generalize recent results in two-dimensional Jackiw-Teitelboim gravity to study factorization of the Hilbert space of eternal black holes in quantum gravity with a negative cosmological constant in any dimension. We approach the problem by computing the trace of two-sided observables as a sum over a recently constructed family of semiclassically well-controlled black hole microstates. These microstates, which contain heavy matter shells behind the horizon and form an overcomplete basis of the Hilbert space, exist in any theory of gravity with general relativity as its low energy limit. Using this representation of the microstates, we show that the trace of operators dual to functions of the Hamiltonians of the left and right holographic CFTs factorizes into a product over left and right factors to leading order in the semiclassical limit. Under certain conditions this implies factorization of the Hilbert space.

We show that coupling the SU(2)-valued Skyrme field to the ρ-meson solves the long-standing issue of (in)compressibility in the solitonic Skyrme model. Even by including only one ρπ interaction term, motivated by a holographic-like reduction of Yang-Mills action by Sutcliffe, reduces the compression modulus from K₀ ≃ 1080 MeV, in the massive Skyrme model, to K₀ ≃ 351 MeV.

The decay of the mediator particle into standard model (SM) particles plays a significant role in exploring the dark sector scenario. We consider such a decay, taking the dark photon mediator as an example that mixes with the SM photon. We find that it requires a careful analysis of the decay rate in the presence of an SM vector boson (e.g., Z boson, ρ meson, and true muonium, etc.) nearly degenerate with the mediator particle in mass. The decay rate of the mediator particle calculated in the mass eigenstate basis does not agree with the correct result, given by the imaginary parts of the poles for the vector boson propagators, when the mixing parameter is smaller than a specific value. In such a case, the decay rate calculated by treating the mixing as a perturbative parameter is in agreement with the correct result. We clarify specific values for the mixing parameter quantitatively using several concrete examples of the SM vector bosons degenerate with the dark photon. When the mass mixing between the vector boson and dark photon is smaller (larger) than the decay width of the vector boson, the latter (former) method to calculate the decay rate of the mediator particle gives the correct result.