Hasil untuk "Nuclear and particle physics. Atomic energy. Radioactivity"

Pei-Ming Ho, Hikaru Kawai, Harold C. Steinacker

Abstract The matrix models are non-perturbative formulations of string theory, from which many believe that spacetime arises. The matrix fluctuations around the spacetime thus created should represent both matter and gravitational fields. In this paper, we discuss how the gravitational field emerges from the IIB matrix model. In particular, we consider how diffeomorphism invariance arises and how unitarity is guaranteed in this theory. Specifically, we consider matrices as bilocal fields and discuss how the Lorentz-invariant vacuum and low-energy excitations around it can be expressed. We then discuss how the conditions for the theory to be unitary can be written in terms of bilocal fields. We argue that in the low-energy limit, the bilocal fields are reduced to local fields consisting of a finite number of massless fields and an infinite number of massive fields, satisfying unitarity.

Nephtalí Eliceo Martínez-Pérez, Cupatitzio Ramírez Romero

Abstract An FLRW reduction of $$N=1$$ N = 1 supergravity is troublesome since spatial isotropy prohibits a non-vanishing Rarita–Schwinger field. In view of this, we consider the quadratic form $$\psi _m^{\ \alpha } \psi _{n\alpha }$$ ψ m α ψ n α arising from a particular superspace generalization of the metric tensor. Imposing the FLRW form on this object reduces $$\psi _m^{\ \alpha }$$ ψ m α to a single 2-component spinor $$\phi ^\alpha $$ ϕ α , which becomes the superpartner of both the scale factor a and lapse N, thus inducing the conformal time gauge, $$N=a$$ N = a . Time-reparametrization invariance is restored if we allow for deviations of FLRW form that are proportional to the gauge fields $$N, \psi _0^{\ \alpha }$$ N , ψ 0 α . We determine the allowed supergravity transformations that preserve the resulting FLRW supermultiplets.

Ting Wu, Min Xu, Zhuo Wang et al.

This paper investigates the compatibility of pronounced detachment with improved confinement based on the NBI-heated HL-2A L-mode plasma with low-density. Through impurity seeding, radiation becomes higher at plasma edge and causes edge cooling after pronounced detachment. Turbulent transport is examined in detail by experiments and global integrated simulations. Ion dominant turbulent transport decreases at normalized minor radius $\rho \in \left[ {0.1,{ }0.4} \right],$ and ion temperature increases at $\rho \in \left[ {0,{ }0.8} \right]$ . Edge turbulence and turbulent transport through ion channels decrease significantly, which could result from reduced free energy source due to edge cooling. The reduced edge turbulent transport benefits to decrease the power entering the SOL/divertor. The decreased edge outward transport and increased core electron density and ion temperature make major contributions to the improved plasma confinement after pronounced detachment.

Zhi-zhong Xing

The Casas-Ibarra (CI) parametrization of the Yukawa coupling matrix of Majorana neutrinos is generalized by considering the exact seesaw relation and including non-unitarity of the 3×3 Pontecorvo-Maki-Nakagawa-Sakata (PMNS) flavor mixing matrix. With the help of a full 6×6 Euler-like block description of the flavor structure for the seesaw mechanism, we find that the orthogonal matrix O in the CI parametrization can be expressed as Oij=Mj/miFij with mi and Mj being the masses of light and heavy Majorana neutrinos and Fij consisting of the PMNS and active-sterile flavor mixing parameters (for i,j=1,2,3). Assuming a specific pattern of O is therefore equivalent to imposing some special conditions on the seesaw parameter space.

D. Grekov, C. Albert, Yu. Turkin et al.

The propagation and absorption of the slow waves (SWs) in the three-ion plasma of the Wendelstein 7-X stellarator have been investigated by ray tracing. The aim of the study is to obtain a qualitative notion of the penetration into the plasma and absorption of the wave excited by the potential difference between the antenna conductors and the antenna box. It has been discovered that the rays propagate along the magnetic field lines over a significant distance, up to 6 m, from the antenna. They weakly, to a depth of 0.1 m, penetrate into the plasma. Absorption of the SWs by electrons does not lead to the generation of the currents capable of affecting the plasma equilibrium. Most of the SWs are absorbed beyond the region of ion–ion hybrid resonance in the zone of cyclotron resonance of ^3 He ions at the periphery of the plasma. The ICRH of the three-ion W 7-X plasma will be used to heat ^3 He ions to high energies and simulate the confinement of alpha particles in an optimized stellarator configuration. The presence of a source of hot ^3 He ions, which are poorly confined, at the periphery of the plasma can affect the experimental results.

Wan Zhen Chua, Yikun Jiang

Abstract We study 3d quantum gravity with two asymptotically anti-de Sitter regions, in particular, using its relation with coupled Alekseev-Shatashvili theories and Liouville theory. Expressions for the Hartle-Hawking state, thermal 2n-point functions, torus wormhole correlators and Wheeler-DeWitt wavefunctions in different bases are obtained using the ZZ boundary states in Liouville theory. Exact results in 2d Jackiw-Teitelboim (JT) gravity are uplifted to 3d gravity, with two copies of Liouville theory in 3d gravity playing a similar role as Schwarzian theory in JT gravity. The connection between 3d gravity and the Liouville ZZ boundary states are manifested by viewing BTZ black holes as Maldacena-Maoz wormholes, with the two wormhole boundaries glued along the ZZ boundaries. In this work, we also study the factorization problem of the Hartle-Hawking state in 3d gravity. With the relevant defect operator that imposes the necessary topological constraint for contractibility, the trace formula in gravity is modified in computing the entanglement entropy. This trace matches with the one from von Neumann algebra considerations, further reproducing the Bekenstein-Hawking area formula from entanglement entropy. Lastly, we propose a calculation for off-shell geometrical quantities that are responsible for the ramp behavior in the late time two-point functions, which follows from the understanding of the Liouville FZZT boundary states in the context of 3d gravity, and the identification between Verlinde loop operators in Liouville theory and “baby universe” operators in 3d gravity.

Vladimir A. Dogiel, Chung-Ming Ko

Two enigmatic gamma-ray features in the galactic central region, known as Fermi Bubbles (FBs), were found from Fermi-LAT data. An energy release, (e.g., by tidal disruption events in the Galactic Center, GC), generates a cavity with a shock that expands into the local ambient medium of the galactic halo. A decade or so ago, a phenomenological model of the FBs was suggested as a result of routine star disruptions by the supermassive black hole in the GC which might provide enough energy for large-scale structures, like the FBs. In 2020, analytical and numerical models of the FBs as a process of routine tidal disruption of stars near the GC were developed; these disruption events can provide enough cumulative energy to form and maintain large-scale structures like the FBs. The disruption events are expected to be <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mn>10</mn><mrow><mo>−</mo><mn>4</mn></mrow></msup><mo>∼</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>5</mn></mrow></msup><msup><mi>yr</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>, providing an average power of energy release from the GC into the halo of <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mover accent="true"><mi mathvariant="script">E</mi><mo>˙</mo></mover><mo>∼</mo><mn>3</mn><mo>×</mo><msup><mn>10</mn><mn>41</mn></msup></mrow></semantics></math></inline-formula> erg <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><msup><mi mathvariant="normal">s</mi><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></semantics></math></inline-formula>, which is needed to support the FBs. Analysis of the evolution of superbubbles in exponentially stratified disks concluded that the FB envelope would be destroyed by the Rayleigh–Taylor (RT) instabilities at late stages. The shell is composed of swept-up gas of the bubble, whose thickness is much thinner in comparison to the size of the envelope. We assume that hydrodynamic turbulence is excited in the FB envelope by the RT instability. In this case, the universal energy spectrum of turbulence may be developed in the inertial range of wavenumbers of fluctuations (the Kolmogorov–Obukhov spectrum). From our model we suppose the power of the FBs is transformed partly into the energy of hydrodynamic turbulence in the envelope. If so, hydrodynamic turbulence may generate MHD fluctuations, which accelerate cosmic rays there and generate gamma-ray and radio emission from the FBs. We hope that this model may interpret the observed nonthermal emission from the bubbles.

Mark D. Goodsell, Ari Joury

Abstract Active learning (AL) has interesting features for parameter scans of new models. We show on a variety of models that AL scans bring large efficiency gains to the traditionally tedious work of finding boundaries for BSM models. In the MSSM, this approach produces more accurate bounds. In light of our prior publication, we further refine the exploration of the parameter space of the SMSQQ model, and update the maximum mass of a dark matter singlet to 48.4 TeV. Finally we show that this technique is especially useful in more complex models like the MDGSSM.

Guang-Liang Li, Xiaotian Xu, Kun Hao et al.

Abstract We generalize the nested off-diagonal Bethe ansatz method to study the quantum chain associated with the twisted D 3 2 $$ {D}_3^{(2)} $$ algebra (or the D 3 2 $$ {D}_3^{(2)} $$ model) with either periodic or integrable open boundary conditions. We obtain the intrinsic operator product identities among the fused transfer matrices and find a way to close the recursive fusion relations, which makes it possible to determinate eigenvalues of transfer matrices with an arbitrary anisotropic parameter η. Based on them, and the asymptotic behaviors and values at certain points, we construct eigenvalues of transfer matrices in terms of homogeneous T − Q relations for the periodic case and inhomogeneous ones for the open case with some off-diagonal boundary reflections. The associated Bethe ansatz equations are also given. The method and results in this paper can be generalized to the D n + 1 2 $$ {D}_{n+1}^{(2)} $$ model and other high rank integrable models.

Matthew Yu

Abstract We investigate the interactions of discrete zero-form and one-form global symmetries in (1+1)d theories. Focus is put on the interactions that the symmetries can have on each other, which in this low dimension result in 2-group symmetries or symmetry fractionalization. A large part of the discussion will be to understand a major feature in (1+1)d: the multiple sectors into which a theory decomposes. We perform gauging of the one-form symmetry, and remark on the effects this has on our theories, especially in the case when there is a global 2-group symmetry. We also implement the spectral sequence to calculate anomalies for the 2-group theories and symmetry fractionalized theory in the bosonic and fermionic cases. Lastly, we discuss topological manipulations on the operators which implement the symmetries, and draw insights on the (1+1)d effects of such manipulations by coupling to a bulk (2+1)d theory.

Masahiro Ibe, Shin Kobayashi, Yuhei Nakayama et al.

Abstract We discuss gauge mediated supersymmetry breaking models which explain the observed muon anomalous magnetic moment and the Higgs boson mass simultaneously. The successful explanation requires the messenger sector which violates the relation motivated by the grand unification theory (GUT). The naive violation of the GUT relation, however, ends up with the CP problem. We propose a model in which the phases of the gaugino masses are aligned despite the violation of the GUT relation. We also consider a model which generates the μ-term and the additional Higgs soft masses squared without causing CP violation. As a result, we find a successful model which explains the muon anomalous magnetic moment and the Higgs boson mass. The model is also free from the CP, flavor-changing neutral current and the lepton flavor violation problems caused by the subdominant gravity mediation effects. The lightest supersymmetric particles are gravitino/goldstini and the next-to-lightest ones are the Wino/Higgsinos in the typical parameter space. We also study the LHC constraints.

G. Papadopoulos

Abstract We show that the Killing spinor equations of all supergravity theories which may include higher order corrections on a (r,s)-signature spacetime are associated with twisted covariant form hierarchies. These hierarchies are characterized by a connection on the space of forms which may not be degree preserving. As a consequence we demonstrate that the form Killing spinor bi-linears of all supersymmetric backgrounds satisfy a suitable generalization of conformal Killing-Yano equation with respect to this connection. To illustrate the general proof the twisted covariant form hierarchies of some supergravity theories in 4, 5, 6, 10 and 11 dimensions are also presented.

Shota Komatsu, Yifan Wang

The four dimensional N=4 super-Yang-Mills (SYM) theory exhibits rich dynamics in the presence of codimension-one conformal defects. The new structure constants of the extended operator algebra consist of one-point functions of local operators which are nonvanishing due to the defect insertion and carry nontrivial coupling dependence. We study an important class of half-BPS superconformal defects engineered by D5 branes that share three common directions with the D3 branes and involve Nahm pole configurations for the SYM fields on the D3 brane worldvolume. In the planar large N limit, we obtain non-perturbative results in the 't Hooft coupling λ for the defect one-point functions of both BPS and non-BPS operators, building upon recent progress in localization [1] and integrability methods [2,3].For BPS operator insertions in the SYM with D5-brane type boundary or interface, we derive an effective two dimensional defect-Yang-Mills (dYM) theory from supersymmetric localization, which gives an efficient way to extract defect observables and generates a novel matrix model for the defect one-point function. By solving the matrix model in the large N limit, we obtain exact results in λ which interpolate between perturbative Feynman diagram contributions in the weak coupling limit and IIB string theory predictions on AdS5×S5 in the strong coupling regime, providing a precision test of AdS/CFT with interface defects. For general non-BPS operators, we develop a non-perturbative bootstrap-type program for integrable boundary states on the worldsheet of the IIB string theory, corresponding to the interface defects in the planar SYM. Such integrable boundary states are constrained by a set of general consistency conditions for which we present explicit solutions that reproduce and extend the known results at weak coupling from integrable spin-chain methods.

Claudia de Rham, Scott Melville, Andrew J. Tolley et al.

Abstract We apply the recently developed positivity bounds for particles with spin, applied away from the forward limit, to the low energy effective theories of massive spin-1 and spin-2 theories. For spin-1 theories, we consider the generic Proca EFT which arises at low energies from a heavy Higgs mechanism, and the special case of a charged Galileon for which the EFT is reorganized by the Galileon symmetry. For spin-2, we consider generic Λ5 massive gravity theories and the special ‘ghost-free’ Λ3 theories. Remarkably we find that at the level of 2-2 scattering, the positivity bounds applied to Λ5 massive gravity theories, impose the special tunings which generate the Λ3 structure. For Λ3 massive gravity theories, the island of positivity derived in the forward limit appears relatively stable against further bounds.

Evgeny I. Buchbinde, Daniel Hutchings, Jessica Hutomo et al.

Abstract The off-shell actions for N $$ \mathcal{N} $$ -extended conformal supergravity theories in three dimensions were formulated in [1, 2] for 1 ≤ N $$ \mathcal{N} $$ ≤ 6 using a universal approach. Each action is generated by a closed super three-form which is constructed in terms of the constrained geometry of N $$ \mathcal{N} $$ -extended conformal superspace. In this paper we initiate a program to recast these actions (and to formulate their higher-spin counterparts) in terms of unconstrained gauge prepotentials as integrals over the full superspace. We derive transverse projection operators in N $$ \mathcal{N} $$ -extended Minkowski superspace and then use them to construct linearised rank-n super-Cotton tensors and off-shell N $$ \mathcal{N} $$ -extended superconformal actions. We also propose off-shell gauge-invariant actions to describe massive higher-spin super-multiplets in N $$ \mathcal{N} $$ -extended supersymmetry. Our analysis leads to general expressions for identically conserved higher-spin current multiplets in N $$ \mathcal{N} $$ -extended supersymmetry.

Halil Mutuk, Yasemin Saraç, Hasan Gümüş et al.

Abstract X(3872) presents many surprises after its discovery more than ten years ago. Understanding its properties is crucial to understand the spectrum of possible exotic mesons. In this work, X(3872) meson and its heavy quark spin symmetry (HQSS) partners (including the mesons in the bottom sector) are studied within the QCD Sum Rules approach using a current motivated by the molecular picture of X(3872). We predict four heavy partners to X(3872) and bottomonium with the masses and $$J^{PC}$$ JPC quantum numbers. Obtained results are in good agreement with the previous studies and available experimental data within errors.

James Colgan, Christopher J. Fontes, Honglin Zhang et al.

We discuss new collisional-radiative modeling calculations of tungsten at moderate temperatures of 1200 to 2400 eV. Such plasma conditions are relevant to ongoing experimental work at ASDEX Upgrade and are expected to be relevant for ITER. Our calculations are made using the Los Alamos National Laboratory (LANL) collisional-radiative modeling ATOMIC code. These calculations formed part of a submission to the recent NLTE-8 workshop that was held in November 2013. This series of workshops provides a forum for detailed comparison of plasma and spectral quantities from NLTE collisional-radiative modeling codes. We focus on the LANL ATOMIC calculations for tungsten that were submitted to the NLTE-8 workshop and discuss different models that were constructed to predict the tungsten emission. In particular, we discuss comparisons between semi-relativistic configuration-average and fully relativistic configuration-average calculations. We also present semi-relativistic calculations that include fine-structure detail, and discuss the difficult problem of ensuring completeness with respect to the number of configurations included in a CR calculation.

G. Bauer

Yoji Nakajima, Takashi Sato

A mathematical model based on an ideal LDV (Laser Doppler Velocimeter) signal indicates that the phase and amplitude of a light scattering particle vibrating sinusoidally within the interference fringes can be obtained from the Fourier integrals of the signal. Although actual LDV signals are distorted, it is found empirically that the use of a Hanning window is very effective for the removal of the undesirable effect of distortion. Hence the size and electrostatic charge of a particle being excited in an AC electric field can be calculated using the Fourier analysis of the LDV signal. A computer simulation shows that the phase can be determined very accurately, say, within 0.1º error if so desired. The lower limit of the amplitude measurement is ca. 0.2 μm within a few percent relative error. Therefore the present method is expected to provide a convenient device for measuring the size and the charge of particles of around 1 μm in diameter. † This report was originally printed in FUNSAI No.35, 11-20 (1991) in Japanese, before being translated into English with the permission of Hosokawa Micron Corporation, Japan.

J. A. Gowan