Towards the robustness of the Affleck-Dine baryogenesis

We study the Affleck-Dine mechanism with various types of the Kahler potential, and investigate whether or not the Affleck-Dine field could acquire a large VEV as an initial condition for successful baryogenesis. In addition to a negative Hubble-induced mass term, we find that large enough Hubble-induced A-terms could also develop the minimum at large amplitude of the field. Therefore, the Affleck-Dine mechanism works for broader classes of the theories.Comment: 6 page

Q-ball formation: Obstacle to Affleck-Dine baryogenesis in the gauge-mediated SUSY breaking ?

We consider the Affleck-Dine baryogenesis comprehensively in the minimal supersymmetric standard model with gauge-mediated supersymmetry breaking. Considering the high temperature effects, we see that the Affleck-Dine field is naturally deformed into the form of the Q ball. In the natural scenario where the initial amplitude of the field and the A-terms are both determined by the nonrenormalizable superpotential, we obtain only very a narrow allowed region in the parameter space in order to explain the baryon number of the universe for the case that the Q-ball formation occurs just after baryon number production. Moreover, most of the parameter sets suited have already been excluded by current experiments. We also find new situations in which the Q-ball formation takes place rather late compared with baryon number creation. This situation is more preferable, since it allows a wider parameter region for naturally consistent scenarios, although it is still difficult to realize in the actual cosmological scenario.Comment: 27 pages, RevTeX, 21 postscript figures included. The version to be publishe

Affleck-Dine mechanism with negative thermal logarithmic potential

We investigate whether the Affleck-Dine (AD) mechanism works when the contribution of the two-loop thermal correction to the potential is negative in the gauge-mediated supersymmetry breaking models. The AD field is trapped far away from the origin by the negative thermal correction for a long time until the temperature of the universe becomes low enough. The most striking feature is that the Hubble parameter becomes much smaller than the mass scale of the radial component of the AD field, during the trap. Then, the amplitude of the AD field decreases so slowly that the baryon number is not fixed even after the onset of radial oscillation. The resultant baryon asymmetry crucially depends on whether the Hubble parameter, $H$, is larger than the mass scale of the phase component of the AD field, $M_\theta$, at the beginning of oscillation. If $H < M_\theta$ holds, the formation of Q balls plays an essential role to determine the baryon number, which is found to be washed out due to the nonlinear dynamics of Q-ball formation. On the other hand, if $H > M_\theta$ holds, it is found that the dynamics of Q-ball formation does not affect the baryon asymmetry, and that it is possible to generate the right amount of the baryon asymmetry.Comment: 18 pages, RevTeX4, 9 postscript figures included, final version to appear in Phys.Rev.

Early reionization by decaying particles and cosmic microwave background radiation

We study the reionization scenario in which ionizing UV photons emitted from decaying particle, in addition to usual contributions from stars and quasars, ionize the universe. It is found that the scenario is consistent with both the first year data of the Wilkinson Microwave Anisotropy Probe and the fact that the universe is not fully ionized until z \sim 6 as observed by Sloan Digital Sky Survey. Likelihood analysis revealed that rather broad parameter space can be chosen. This scenario will be discriminated by future observations, especially by the EE polarization power spectrum of cosmic microwave background radiation.Comment: 5 pages, 5 figures, fig 2, table 1, and some typos are correcte

Q-ball formation in the wake of Hubble-induced radiative corrections

We discuss some interesting aspects of the $\rm Q$-ball formation during the early oscillations of the flat directions. These oscillations are triggered by the running of soft $({\rm mass})^2$ stemming from the nonzero energy density of the Universe. However, this is quite different from the standard $\rm Q$-ball formation. The running in presence of gauge and Yukawa couplings becomes strong if $m_{1/2}/m_0$ is sufficiently large. Moreover, the $\rm Q$-balls which are formed during the early oscillations constantly evolve, due to the redshift of the Hubble-induced soft mass, until the low-energy supersymmtery breaking becomes dominant. For smaller $m_{1/2}/m_0$, $\rm Q$-balls are not formed during early oscillations because of the shrinking of the instability band due to the Hubble expansion. In this case the $\rm Q$-balls are formed only at the weak scale, but typically carry smaller charges, as a result of their amplitude redshift. Therefore, the Hubble-induced corrections to the flat directions give rise to a successful $\rm Q$-ball cosmology.Comment: 7 revtex pages, few references corrected and added, final version to appear in Phys. Rev.

Impact of dark matter decays and annihilations on reionization

One of the possible methods to distinguish among various dark matter candidates is to study the effects of dark matter decays. We consider four different dark matter candidates (light dark matter, gravitinos, neutralinos and sterile neutrinos), for each of them deriving the decaying/annihilation rate, the influence on reionization, matter temperature and CMB spectra. We find that light dark matter particles (1-10 MeV) and sterile neutrinos (2-8 keV) can be sources of partial early reionization (z<~100). However, their integrated contribution to Thomson optical depth is small (<~0.01) with respect to the three year WMAP results (tau_e=0.09+/-0.03). Finally, they can significantly affect the behavior of matter temperature. On the contrary, effects of heavy dark matter candidates (gravitinos and neutralinos) on reionization and heating are minimal. All the considered dark matter particles have completely negligible effects on the CMB spectra.Comment: 6 pages, 5 figures; MNRAS, in pres

On the Moduli Problem and Baryogenesis in Gauge-mediated SUSY Breaking Models

We investigate whether the Affleck-Dine mechanism can produce sufficient baryon number of the universe in the gauge-mediated SUSY breaking models, while evading the cosmological moduli problem by late-time entropy production. We find that the Q-ball formation renders the scenario very difficult to work, irrespective of the detail mechanism of the entropy production.Comment: 11 pages, RevTeX, 5 postscript figures include

Money Matters: An Educational Intervention to Improve Financial Wellness and Literacy Among Medical Students

Objective or purpose of innovation: We created a curriculum for medical students that targets gaps in personal finance and assessed self-perception of financial wellness and literacy. Background and/or theoretical framework and importance to the field: Financial stressors associated with student loan debt and poor financial literacy leads to burnout among medical students and professionals. Providing earlier financial training may inform proactive planning and improve overall wellness. Design: First-year medical students participated in an education activity covering topics such as personal finance, budgeting, student loans, and loan repayment programs. Participants reviewed informational handouts and watched pre-recorded videos followed by a faculty-led debrief in small groups. A 12-question survey was delivered to participants after the activity to retrospectively evaluate self-perception of financial literacy before and after the curricular intervention (retrospective pre-post approach). Likert-scale items (1:4, strongly disagree: strongly agree) were used. Pre- and post-activity mean scores were compared using paired t-tests. Outcomes: Out of the 77 participants, 69 (90%) completed the survey. Overall, participants felt more confident in their personal financial knowledge (2.38 vs 3.06, p<.001), and 98% of participants agreed that this activity motivated them to learn more about financial literacy. For debt management, participants felt more confident in building a strategy to manage financial debt (2.77 vs 3.33, p<0.001), cultivated a better understanding of loan terms (2.49 vs 3.57, p<0.001), and became more aware of loan repayment options (2.43 vs 3.51, p<0.001). All participants agreed that this activity should be continued for future medical students (27% somewhat agree, 73% strongly agree). Innovation’s strengths and limitations: Financial literacy education is associated with improved understanding, confidence, and appreciation of personal finance among medical students and should be considered for inclusion in other medical education programs. Feasibility and generalizability: A short instructional video combined with group discussion can be an effective model for addressing this sometimes under-appreciated aspect of student wellness

Numerical simulations of fragmentation of the Affleck-Dine condensate

We present numerical simulations of fragmentation of the Affleck-Dine condensate in two spatial dimensions. We argue analytically that the final state should consist of both Q-balls and anti-Q-balls in a state of maximum entropy, with most of the balls small and relativistic. Such a behaviour is found in simulations on a 100x100 lattice with cosmologically realistic parameter values. During fragmentation process, we observe filament-like texture in the spatial distribution of charge. The total charge in Q-balls is found to be almost equal to the charge in anti-Q-balls and typically orders of magnitude larger than charge asymmetry. Analytical considerations indicate that, apart from geometrical factors, the results of the simulated two dimensional case should apply also to the fully realistic three dimensional case.Comment: 28 pages, 39 figure

Reheating as a surface effect

We describe a new mechanism for reheating the Universe through evaporation of a surface charge of a fragmented inflaton condensate. We show that for a range of Yukawa coupling of the inflaton to the matter sector evaporation gives rise to a much smaller reheat temperature compared to the standard perturbative decay. As a consequence, reheating through a surface effect could solve the gravitino and moduli over production problem in inflationary models without fine tuning the Yukawa sector.Comment: 4 page