Massive Spinning Particle Research Articles

Holographic entanglement entropy in AdS3/WCFT

In this paper, we consider AdS3 with Compère-Song-Strominger (CSS) boundary conditions, under which the dual field theory is warped conformal field theory (WCFT), featuring a Virasoro-Kac-Moody algebra. We provide a holographic dual picture of the single interval entanglement entropy in WCFT in the bulk AdS3. We explicitly show that the bulk object captures the entanglement entropy in WCFT is a massive spinning particle's worldline that anchored on the boundary of the interval. Given the mass and spin of the particle as functions of quantum numbers of the twist operator in WCFT, the on-shell worldline action will match the entanglement entropy in WCFT.

Phenomenology of nuclear scattering for a WIMP of arbitrary spin

We provide a first systematic and quantitative discussion of the phenomenology of the nonrelativistic effective Hamiltonian describing the nuclear scattering process for a weakly interacting massive particle (WIMP) of arbitrary spin ${j}_{\ensuremath{\chi}}$. To this aim we obtain constraints from a representative sample of present direct detection experiments assuming the WIMP-nucleus scattering process to be driven by each one of the 44 effective couplings that arise for ${j}_{\ensuremath{\chi}}\ensuremath{\le}2$. We find that a high value of the multipolarity $s\ensuremath{\le}2{j}_{\ensuremath{\chi}}$ of the coupling, related to the power of the momentum transfer $q$ appearing in the scattering amplitude, leads to a suppression of the expected rates and pushes the expected differential spectra to large recoil energies ${E}_{R}$. For $s\ensuremath{\le}4$ the effective scales probed by direct detection experiments can be suppressed by up to five orders of magnitude compared to the case of a standard spin-independent interaction. For operators with large $s$ the expected differential spectra can be pushed to recoil energies in the MeV range, with the largest part of the signal concentrated at ${E}_{R}\ensuremath{\gtrsim}100\text{ }\text{ }\mathrm{keV}$ and a peculiar structure of peaks and minima arising when both the nuclear target and the WIMPs are heavy. As a consequence the present bounds on the effective operators can be significantly improved by extending the recoil energy intervals to higher recoil energies. Our analysis assumes effective interaction operators that are irreducible under the rotation group. Such operators drive the interactions of high-multipole dark matter candidates, i.e., states that possess only the highest multipole allowed by their spin. As a consequence our analysis represents also the first phenomenological study of the direct detection of quadrupolar, octupolar, and hexadecapolar dark matter.

Searching for the dark sector in two-body antimuon decay with the polarization of monochromatic positrons

The $\mu^+ \to e^+ X$ decay, where $X$ is a dark sector boson, provides one of the strongest available bounds on the scale of dark sector interactions. The $X$ boson can be an axion or a dark photon. We show that the concurrent determination of the anti-muon and positron polarizations makes possible to distinguish with a confidence level of 99% between the two dark sector portals with as few as 6 observed events in the case of the massless dark photon. Instead, the massive spin-1, dimension 4 dark portal cannot be distinguished from the axion-like case. We also discuss the possibility that the $X$ boson be a massive spin-2 particle.

The relativistic spherical top as a massive twistor

We prove the equivalence between two traditional approaches to the classical mechanics of a massive spinning particle in special relativity. One is the spherical top model of Hanson and Regge, recast in a Hamiltonian formulation with improved treatment of covariant spin constraints. The other is the massive twistor model, slightly generalized to incorporate the Regge trajectory relating the mass to the total spin angular momentum. We establish the equivalence by computing the Dirac brackets of the physical phase space carrying three translation and three rotation degrees of freedom. Lorentz covariance and little group covariance uniquely determine the structure of the physical phase space. The Regge trajectory does not affect the phase space but enters the equations of motion. Upon quantization, the twistor model produces a spectrum that agrees perfectly with the massive spinor-helicity description proposed by Arkani-Hamed, Huang and Huang for scattering amplitudes for all masses and spins.

Effective theory for self-interacting dark matter and massive spin-2 mediators

We consider the effective theory for self-interacting dark matter with arbitrary spin and go beyond the previous discussion in the literature by introducing a massive spin-2 particle as the mediator for dark matter (DM) self-scattering. We present effective self-interactions for DM in the leading order expansions with momentum transfer and DM velocity. We compare the Born cross section and the non-perturbative cross section in the leading-order approximation of the effective Yukawa interaction. As a result, we find that there is a wide range of DM and spin-2 particle masses for velocity-dependent self-scattering to solve small-scale problems in galaxies and to satisfy the bounds from galaxy clusters at the same time.

Collisional Penrose process of 4D rotational Einstein-Gauss-Bonnet black holes * *Supported by the National Natural Science Foundation of China (NSFC) (11775082)

The collisional Penrose process of massive spinning particles in a rotational Einstein-Gauss-Bonnet (EGB) black hole background is studied. By numerically solving the equations of motion for spinning particles, we find that the energy extraction efficiency increases monotonically with the decrease of the EGB coupling parameter . Moreover, the efficiency increases as the particle spin s grows. We also find that the energy extraction efficiency increases with the decrease of the EGB coupling parameter . When the EGB coupling constant , our results reduce to the Kerr case, which has been investigated previously.

Study of spinning particles around rotating black holes‎

The orbital velocity profile around the Kerr black holes has a non-monotonic radial behavior in the Locally ‎Nonrotating Frames (LNRF)‎. ‎Using Mathisson- Papapetrou- Dixon equation for a massive spinning particle‎, ‎again this ‎maximum-minimum feature has been shown by considering the linear spin approximation‎. ‎Also the spin of black holes ‎and absolute value of particle's spin have an important rule ‏ ‏in Aschenbach effect‎‎.

Gravity with dynamical torsion

We propose four simple Lagrangians for gravity models with dynamical torsion which are free from ghosts and tachyons. The torsion propagates two massive or massless particles of spin 1± and 0± besides the massless graviton 2+ propagated by metric.

Aschenbach effect for spinning particles in Kerr spacetime

The orbital velocity profile of circular timelike geodesics in the equatorial plane of a Kerr black hole has a non-monotonic radial behavior, provided that the spin parameter $a$ of the black hole is bigger than a certain critical value $a_c \approx 0.9953 M$. Here the orbital velocity is measured with respect to the Locally Non-Rotating Frame (LNRF), and the non-monotonic behavior, which is known as the Aschenbach effect, occurs only for co-rotating orbits. Using the Mathisson-Papapetrou-Dixon equations for a massive spinning particle, we investigate the Aschenbach effect for test particles with spin. In addition to the black-hole spin, the absolute value of the particle's spin and its orientation (parallel or anti-parallel to the black-hole spin) also play an important role for the Aschenbach effect. We determine the critical value $a_c$ of the spin parameter of the Kerr black hole where the Aschenbach effect sets in as a function of the spin of the probe. We consider not only black holes ($a^2 \le M^2$) but also naked singularities ($a^2>M^2$). Whereas for spinless (geodesic) particles the orbital velocity is always monotonically decreasing if the motion is counter-rotating, we find that for spinning particles in counter-rotating motion with anti-parallel spin around a naked singularity the orbital velocity is increasing on a certain radius interval.

Lightening gravity-mediated dark matter

We revisit the scenario of a massive spin-2 particle as the mediator for communicating between dark matter of arbitrary spin and the Standard Model. Taking the general couplings of the spin-2 particle in the effective theory, we discuss the thermal production mechanisms for dark matter with various channels and the dark matter self-scattering. For WIMP and light dark matter cases, we impose the relic density condition and various experimental constraints from direct and indirect detections, precision measurements as well as collider experiments. We show that it is important to include the annihilation of dark matter into a pair of spin-2 particles in both allowed and forbidden regimes, thus opening up the consistent parameter space for dark matter. The benchmark models of the spin-2 mediator are presented in the context of the warped extra dimension and compared to the simplified models.

More on dual actions for massive spin-2 particles

Here we start from a dual version of Vasiliev’s first order action for massless spin-2 particles (linearized first order Einstein–Hilbert) and derive, via Kaluza–Klein dimensional reduction from D + 1 to D dimensions, a set of dual massive spin-2 models. This set includes the massive ‘BR’ model, a spin-2 analogue of the spin-1 Cremmer–Scherk model. In our approach the linearized Riemann curvature emerges from a solution of a functional constraint. In D = 2 + 1 the BR model can be written as a linearized version of a new bimetric model for massive gravitons. We also have a new massive spin-2 model, in arbitrary dimensions, invariant under linearized diffeomorphisms. It is given in terms of a non symmetric rank-2 tensor and a mixed symmetry tensor.

Supersymmetric quantum mechanics requires g=2 for vector bosons

Relativistic arbitrary spin Hamiltonians are shown to obey the algebraic structure of supersymmetric quantum system if their odd and even parts commute. This condition is identical to that required for the exactness of the Foldy-Wouthuysen transformation. Applied to a massive charged spin-1 particle in a constant magnetic field, supersymmetric quantum mechanics necessarily requires a gyromagnetic factor g = 2.

Polarization transfer from the twisted light to an atom

When polarized light is absorbed by an atom, the excited atomic system carries information about the initial polarization of light. For the light that carries an orbital angular momentum, or the twisted light, the polarization states are described by eight independent parameters, as opposed to three Stokes parameters for plane waves. We use a parameterization of the spin-density matrix of the twisted light in terms of vector and tensor polarization, in analogy with massive spin-1 particles, and derive formulae that define atom’s response to specific polarization components of the twisted light. It is shown that for dipole (S → P) atomic transitions, the atom’s polarization is in one-to-one correspondence with polarization of the incident light; this relation is violated, however, for the transitions of higher multipolarity (S → D, S → F, etc) We pay special attention to contributions of the longitudinal electric field into the matrix elements of atomic transitions.

Matter coupling in massive gravity

We discuss the dRGT massive gravity interacting with spin-0, spin-1/2, or spin-1 matter. The effective theory of a massive spin-2 particle coupled to matter particles is constructed directly at the amplitude level. In this setting we calculate the gravitational Compton scattering amplitudes and study their UV properties. While the Compton am- plitudes generically grow with energy as O(E6), we identify regions of the parameter space where they are softened to O(E4) or even O(E3), which allows for a larger validity range of the effective theory. In these regions, both positivity and beyond-positivity of the forward Compton amplitudes are fulfilled, and the equivalence principle automatically emerges.

Effect of the GUP on the Hawking radiation of black hole in 2 + 1 dimensions with quintessence and charged BTZ-like magnetic black hole

In this paper, we investigate the Hawking radiation process by using the quantum tunneling phenomenon of massive spin-1 (W-bosons) and spin-0 particles by the black hole in 2 + 1 dimensions surrounded by quintessence as well as charged BTZ-like magnetic black hole. First of all, by using Hamilton–Jacobi ansatz and WKB approximation to the field equation of massive vector particles, we get the required tunneling rate of emitted particles and obtain the corresponding Hawking temperature [Formula: see text] for the black hole (BH) surrounded by quintessence. In order to study the quantum gravity effects, we utilize the generalized Proca and Klein–Gordan equations incorporating the generalized uncertainty principle (GUP) for these BHs and recover their modified tunneling probability as well as accompanying quantum corrected temperatures [Formula: see text].

UV constraints on massive spinning particles: lessons from the gravitino

Self-interacting massive particles with spin ≥ 1 unavoidably violate unitarity; the question is at what scale. For spin-1 the strong coupling scale (at which perturbative unitarity is lost) cannot be raised by any finite tuning of the interactions, while for spin-2 there exists a special tuning of the Wilson coefficients which can raise this scale (and enjoys numerous special properties such as ghost-freedom). Here, we fill in the missing piece by describing how the self-interactions of a massive spin-3/2 field, or “massive gravitino”, become strongly coupled at high energies. We show that while several different structures appear in the leading order potential, the strong coupling scale cannot be raised (in the absence of additional fields). At the level of the off-shell Lagrangian, it is always the non- linear symmetries of the longitudinal Stückelberg mode that dictate the strong coupling, and we show that in general it is only possible to parametrically raise the strong coupling scale if Wess-Zumino structures exist for these symmetries. We complement this off-shell approach with a first analysis of positivity bounds for a massive spin-3/2 particle, showing that any potential self-interaction which contributes to an on-shell 2-to-2 elastic process at tree level must vanish if this low-energy theory is to have a standard UV completion. We identify the mixing between the longitudinal mode and the transverse modes as the main obstacle to positivity, and clarify how the non-Abelian nature of non-linear (dRGT) massive gravity allows it to satisfy positivity where all known spin ≥ 3/2 Abelian theories fail. Our results imply that a massive gravitino cannot appear alone in a controlled EFT — it must be accompanied by other particles, e.g. as part of a supermultiplet. Together with the spin-1 and spin-2 cases, we suggest features which will persist in even higher spin massive theories.

Unitarity of higher derivative spin-3 models

The fourth order in derivatives New Massive Gravity model NMG, describes a massive spin-2 particle in D=2+1. At the linearized level a proof of unitarity necessarily implies that the generalization to higher dimensions includes non-unitary massless spin-2 modes. The linearized version of NMG is dual to the Fierz-Pauli model FP. Here we examine the unitarity of higher derivative spin-3 models, analogous to the NMG, dual to the Singh-Hagen model SH. We find that the same kind of restriction on the dimension of the space also happens in this case, and the models are physical only in D=2+1.

Constraints on a gravitational Higgs mechanism

We show that it is impossible to improve the high-energy behavior of the tree-level four-point amplitude of a massive spin-2 particle by including the exchange of any number of scalars and vectors in four spacetime dimensions. This constrains possible weakly coupled ultraviolet extensions of massive gravity, ruling out gravitational analogues of the Higgs mechanism based on particles with spins less than two. Any tree-level ultraviolet extension that is Lorentz invariant and unitary must involve additional massive particles with spins greater than or equal to two, as in Kaluza-Klein theories and string theory.

Geometrical model of massive spinning particle in four-dimensional Minkowski space

We propose the model of a massive spinning particle traveling in four-dimensional Minkowski space. The equations of motion of the particle are obtained from the requirement that its classical paths lie on a cylinder with the time-like axis in Minkowski space. All the paths on one and the same cylinder are gauge equivalent. The equations of motion are found in implicit form for general time-like paths, and they are non-Lagrangian. The explicit equations of motion are derived for trajectories with small curvature and helices. The momentum and total angular momentum are expressed in terms of characteristics of the path in all the cases. The constructed model of the spinning particle has a geometrical character, with no additional variables in the space of spin states being introduced.

Structure constants from modularity in warped CFT

We derive a universal formula for the asymptotic growth of the mean value of three-point coefficient for Warped Conformal Field Theories (WCFTs), and provide a holographic calculation in BTZ black holes. WCFTs are two dimensional quantum field theories featuring a chiral Virasoro and U(1) Kac-Moody algebra, and are conjectured to be holographically dual to quantum gravity on asymptotically AdS3 spacetime with Compère- Song-Strominger boundary conditions. The WCFT calculation amounts to the calculation of one-point functions on torus, whose high temperature limit can be approximated by using modular covariance of WCFT, similar to the derivation of Cardy formula. The bulk process is given by a tadpole diagram, with a massive spinning particle propagates from the infinity to the horizon, and splits into particle and antiparticle which annihilate after going around the horizon of BTZ black holes. The agreement between the bulk and WCFT calculations indicates that the black hole geometries in asymptotically AdS3 spacetimes can emerge upon coarse-graining over microstates in WCFTs, similar to the results of Kraus and Maloney in the context of AdS/CFT [1].