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Register a new userThe fate of the Q-balls with one-loop motivated effective potential revisited analytically
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The analytical description on the Friedberg-Lee-Sirlin typed Q-balls is performed. The two-field Q-balls are also discussed under the one-loop motivated effective potential subject to the temperature. We prove strictly to confirm that the parameters from the potential can be regulated to lead the energy per unit charge of Q-balls to be lower to keep the model stable. If the energy density is low enough, the Q-balls can become candidates of dark matter. It is also shown rigorously that the two-field Q-balls can generate in the first-order phase transition and survive while they are affected by the expansion of the universe. The analytical investigations show that the Q-balls with one-loop motivated effective potential can exist with the adjustment of coefficients of terms. We cancel the infinity in the energy to obtain the necessary conditions consist with those imposed in the previous work. According to the explicit expressions, the lower temperature will reduce the energy density, so there probably have been more and more stable Friedberg-Lee-Sirlin typed Q-balls to become the dark matter in the expansion of the universe.
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We discuss the $U(1)$ gauged Q-balls with $N$-power potential to examine their properties analytically. More numerical descriptions and some analytical consideration have been contributed to the models governed by four-power potential. We also demonstrate strictly some new limitations that the stable $U(1)$ gauged Q-balls should accept instead of estimating those with only some specific values of model variables numerically. Having derived the explicit expressions of radius, the Noether charge and energy of the gauged Q-balls, we find that these models under the potential of matter field with general power and the boundary conditions will exist instead of dispersing and decaying. The Noether charge of the large gauged Q-balls must be limited. The mass parameter of the model can not be tiny.
We study the decoupling effects in N=1 (global) supersymmetric theories with chiral superfields at the one-loop level. The examples of gauge neutral chiral superfields with the minimal (renormalizable) as well as non-minimal (non- renormalizable) couplings are considered, and decoupling in gauge theories with U(1) gauge superfields that couple to heavy chiral matter is studied. We calculate the one-loop corrected effective Lagrangians that involve light fields and heavy fields with mass of order M. The elimination of heavy fields by equations of motion leads to decoupling effects with terms that grow logarithmically with M. These corrections renormalize light fields and couplings in the theory (in accordance with the decoupling theorem). When the field theory is an effective theory of the underlying fundamental theory, like superstring theory, where the couplings are calculable, such decoupling effects modify the low-energy predictions for the effective couplings of light fields. In particular, for the class of string vacua with an anomalous U(1) the vacuum restabilization triggers the decoupling effects, which can significantly modify the low energy predictions for the couplings of the surviving light fields. We also demonstrate that quantum corrections to the chiral potential depending on massive background superfields and corresponding to supergraphs with internal massless lines and external massive lines can also arise at the two-loop level.
We study non-topological solitons, so called Q-balls, which carry a non-vanishing Noether charge and arise as lump solutions of self-interacting complex scalar field models. Explicit examples of new axially symmetric non-spinning Q-ball solutions that have not been studied so far are constructed numerically. These solutions can be interpreted as angular excitations of the fundamental $Q$-balls and are related to the spherical harmonics. Correspondingly, they have higher energy and their energy densities possess two local maxima on the positive z-axis. We also study two Q-balls interacting via a potential term in (3+1) dimensions and construct examples of stationary, solitonic-like objects in (3+1)-dimensional flat space-time that consist of two interacting global scalar fields. We concentrate on configurations composed of one spinning and one non-spinning Q-ball and study the parameter-dependence of the energy and charges of the configuration. In addition, we present numerical evidence that for fixed values of the coupling constants two different types of 2-Q-ball solutions exist: solutions with defined parity, but also solutions which are asymmetric with respect to reflexion through the x-y-plane.
Non-topological solitons such as Q-balls and Q-shells have been studied for scalar fields invariant under global and gauged U(1) symmetries. We generalize this framework to include a Proca mass for the gauge boson, which can arise either from spontaneous symmetry breaking or via the Stuckelberg mechanism. A heavy (light) gauge boson leads to solitons reminiscent of the global (gauged) case, but for intermediate values these Proca solitons exhibit completely novel features such as disconnected regions of viable parameter space and Q-shells with unbounded radius. We provide numerical solutions and excellent analytic approximations for both Proca Q-balls and Q-shells. These allow us to not only demonstrate the novel features numerically, but also understand and predict their origin analytically.
We consider the one-loop five-graviton amplitude in type II string theory calculated in the light-cone gauge. Although it is not possible to explicitly evaluate the integrals over the positions of the vertex operators, a low-energy expansion can be obtained, which can then be used to infer terms in the low-energy effective action. After subtracting diagrams due to known D^{2n}R^4 terms, we show the absence of one-loop R^5 and D^2R^5 terms and determine the exact structure of the one-loop D^4R^5 terms where, interestingly, the coefficient in front of the D^4R^5 terms is identical to the coefficient in front of the D^6R^4 term. Finally, we show that, up to D^6R^4 ~ D^4R^5, the epsilon_{10} terms package together with the t_8 terms in the usual combination (t_8t_8pm{1/8}epsilon_{10}epsilon_{10}).
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