Nagatani's Papers and Preprints

[in Japanese]

hep-th/0312060  [PostScript.gz]

Title		Black Hole as a Baryon-Reactor --- Rapid Baryon Number Violation in Black Hole
Authors		Y. Nagatani
Abstract

We find out that baryon numbers of the matter fallen into black holes are rapidly washed-out by investigating the radiation-ball description of the black holes. The radiation-ball solution, which was derived by analyzing the backreaction of the Hawking radiation into space-time and is identified as a black hole, consists of the radiation gravitationally-trapped into the ball and of a singularity. The baryon number of the black hole is defined as that of the radiation in the ball. The sphaleron processes of the Standard Model work in the ball because the proper temperature of the radiation is Planck scale and the Higgs vev becomes zero. The decay-rate of the baryon number becomes \dot{B}/B = -alpha_W^4 / r_BH for the Schwarzschild black hole of radius r_BH. When we assume the baryon number violating processes of the GUT, we find more rapid decay-rate. We can regard the black holes as the baryon-reactors which convert the baryonic matter into energy of radiation.
HEP-SPIRES-SLAC 5742994
arXiv.org hep-th/0312060

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hep-th/0311133  [PostScript.gz]

Title		Radiation Ball for a Charged Black Hole
Authors		Y. Nagatani
Abstract

A radiation-ball solution which is identified as a Reissner-Nordstrom black hole is found out. The radiation-ball, which is derived by analyzing the backreaction of the Hawking radiation into space-time, consists of radiation trapped in a ball by a deep gravitational potential and of a singularity. The Hawking radiation is regarded as a leak-out of the radiation from the ball. The gravitational potential becomes deep as the charge becomes large, however, the basic structure of the ball is independent of the charge. The extremal-charged black hole corresponds with the fully frozen ball by the infinite red-shift. The total entropy of the radiation in the ball, which is independent of the charge, obeys the area-law and is near the Bekenstein entropy.
HEP-SPIRES-SLAC 5727391
arXiv.org hep-th/0311133

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hep-th/0310185  [PostScript.gz]

Title		Radiation Ball as a Black Hole
Authors		Y. Nagatani
Abstract

A structure of the radiation-ball which is identified as a Schwarzschild black hole is found out by investigating the backreaction of Hawking radiation into space-time. The structure consists of the radiation which is gravitationally bounded in the ball and of a singularity. The entropy of the radiation in the ball is proportional to the surface-area of the ball and nearly equals to the Bekenstein entropy. The Hawking radiation is regarded as a leak-out from the ball. There arises no information paradox because there exists no horizon in the structure.
HEP-SPIRES-SLAC 5700345
arXiv.org hep-th/0310185

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hep-th/0307295  [PostScript.gz]

Title		Spherical Domain Wall formed by Field Dynamics of Hawking Radiation and Structure Near Horizon
Authors		Y. Nagatani
Abstract

The Hawking radiation in the vacuum of the spontaneous symmetry breaking in the gauge-Higgs-Yukawa theory is investigated by a general relativistic formulation of the the ballistic model. The restoration of the symmetry on the horizon and the formation of the spherical domain wall around the black hole are shown even if the Hawking temperature is lower than the critical temperature of the phase transition in the gauge-Higgs-Yukawa theory. When the Hawking temperature is much lower than the critical temperature, the domain wall closely near the horizon is formed. The wall is formed by the field dynamics rather than the thermal phase transition.
HEP-SPIRES-SLAC 5625050
arXiv.org hep-th/0307295

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to appear Nuclear Physics B (hep-th/0307294  [PostScript.gz])

Title		Spherical Domain Wall formed by Field Dynamics of Hawking Radiation and Spontaneous Charging-up of Black Hole
Authors		Y. Nagatani
Abstract

We discuss the Hawking radiation in the gauge-Higgs-Yukawa theory. The ballistic model is proposed as an effective description of the system. We find that a spherical domain wall around the black hole is formed by the field dynamics rather than the thermal phase transition. The formation of the wall is a general property of the black hole whose Hawking temperature is equal to or greater than the energy scale of the theory. The formation of the electroweak wall and that of the GUT wall are shown. We also find a phenomenon of the spontaneous charging-up of the black hole with the wall. The Hawking radiation drives a mechanism of the charge-transportation into the black hole when C- and CP-violation are assumed. A black hole whose Hawking-temperature is on the electroweak scale can obtain a large amount of the hyper-charge by the mechanism.
HEP-SPIRES-SLAC 5625041
arXiv.org hep-th/0307294

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hep-th/0203010  [PostScript.gz]

Title		Dynamical Formation of Spherical Domain Wall by Hawking Radiation and Spontaneous Charging-up of Black Hole
Authors		Y. Nagatani
Abstract

We discuss the Hawking radiation in the Higgs-Yukawa system and we show dynamical formation of a spherical domain wall around the black hole. The formation of the spherical wall is a general property of the black hole whose Hawking temperature is equal to or greater than the energy scale of the system. The formation of the electroweak wall and that of the GUT wall are shown as realistic cases. We also discuss a phenomenon of the spontaneous charging-up of the black hole. The Hawking radiation can charge-up the black hole itself by the charge-transportation due to the spherical wall when C- and CP-violation in the wall are assumed. The black hole with the electroweak wall can obtain a large amount of the hyper charge.
HEP-SPIRES-SLAC 4879309
LANL hep-th/0203010

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hep-ph/0104160  [PostScript.gz] : International Workshop COSMO-01 Proceeding

Title		Electroweak/GUT Domain Wall by Hawking Radiation: Baryogenesis and Dark Matter from Several Hundred kg Black Holes
Authors		Y. Nagatani
Abstract

A spherical domain wall around a small black hole is formed by the Hawking radiation from the black hole in the symmetry-broken-phase of the field theory, e.g., the Standard Model (SM) and the Grand Unified Theory (GUT) which have a property of the phase transition. We have obtained two types of the spherical domain wall; (a) thermalized wall which is formed by the local heating up near black hole and symmetry restore locally and (b) dynamical wall which is formed by the balance between the pressure from the Hawking radiation and the pressure from the wall tensions. The electroweak wall is formed as a thermalized wall around a black hole with mass of the several hundred kilogram. The GUT wall is formed as a dynamical wall around much smaller black hole. The electroweak wall around a black hole can produce baryon number by the assumption of the CP-broken phase in the wall. The GUT wall can supply charge into the black hole, namely, the wall causes the spontaneous charging up of the black hole. We propose a cosmological model which can explain the origin of the baryon number and the cold dark matter by the primordial black hole with mass of the several hundred kilogram.
HEP-SPIRES-SLAC 4801121
LANL hep-ph/0112107

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hep-ph/0104160  [PostScript.gz]

Title		Electroweak Domain Wall by Hawking Radiation: Baryogenesis and Dark Matter from Several Hundred kg Black Holes
Authors		Y. Nagatani
Abstract

We show that a spherical electroweak domain wall is formed around a small black hole and this is a general property of the Hawking radiation in the vacuum of the Standard Model. The wall appears not only for the first order phase transition in the electroweak theory but also for the second order one because the black hole heats up its neighborhood locally by the Hawking radiation in any case. We propose a model for unifying the origin of the baryon number and the cold dark matter in our universe by using properties of the primordial black hole with a mass of several hundred kilograms. The interaction between our wall and the Hawking-radiated-particles can create a baryon number which is proportional to the mass of the black hole as well as the CP broken phase in the extension of the Standard Model. Our model can explain both the baryon-entropy ratio B/S \sim 10^{-10} and the energy density of the dark matter, provided that the following three conditions are satisfied: (i) the primordial black holes dominate in the early universe, (ii) the CP broken phase in the wall is in the order of one and (iii) any black hole leaves a stable remnant with a Planck mass after its evaporation. Our model also predicts a cosmological graviton background with a peak-energy 120 \sim 280 eV in the present universe.
HEP-SPIRES-SLAC 4611128
LANL hep-ph/0104160

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Physical Review A 62 (2000) 022117    (hep-th/9904193 [PostScript.gz])

Title		Effective Theoretical Approach to Backreaction of the Dynamical Casimir Effect in 1+1 Dimensions
Authors		Y. Nagatani
Abstract

We present a new approach to study the Casimir effects by means of the effective theory. An essential point of our approach is replacing the mirror-separation into the size of space S^1 in the adiabatic approximation. It is natural to identify the size of space S^1 with the scale factor of the Robertson-Walker type metric. This replacement simplifies the construction of a class of effective models to study the Casimir effects. To check the validity of this replacement we construct a model for a scalar field coupling to the two-dimensional gravity and calculate the Casimir effects by the effective action for the variable scale factor. Our effective action consists of the classical kinetic term of the mirror-separation and the quantum correction derived by the path integral method. The quantum correction naturally contains both the Casimir energy term and the backreaction-term of the dynamical Casimir effect, latter of which is expressed by the conformal anomaly. The resultant effective action describes the dynamical vacuum pressure, i.e., the dynamical Casimir force. We confirm that the force depends on the relative velocity of the mirrors, and that it is always attractive and stronger than the static Casimir force within the adiabatic approximation.
HEP-SPIRES-SLAC 4050991
LANL hep-th/9904193

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Physical Review D 59 (1999) 041301    (hep-ph/9811485 [PostScript.gz])

Title		Electroweak Baryogenesis by Black Holes
Authors		Y. Nagatani
Abstract

We propose a new scenario of the electroweak baryogenesis based on the properties of electroweak domain walls surrounding black holes in the Higgs phase vacuum of the extended Standard Model with 2-Higgs doublets. It is shown that there exists the electroweak domain walls and the symmetric regions surrounding black holes and that the Hawking radiation of the black holes can produce a non-zero baryon number density. The scenario can explain the origin of the baryon number in our universe even without the assumption of the existence of the first order electroweak phase transition. HEP-SPIRES-SLAC 3901165
LANL hep-ph/9811485

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hep-ph/9805455  [PostScript.gz]

Title		Black Hole Baryogenesis
Authors		Y. Nagatani
Abstract

We find that the Hawking radiation of black holes can create the baryon number in the Higgs phase vacuum of the extended standard model with 2-Higgs doublets. We propose new scenarios of baryogenesis based on the black holes, and one of our scenarios can explain the origin of baryon number in our universe, if most of the matter existed as primordial black holes.
HEP-SPIRES-SLAC 3759300
LANL hep-ph/9805455

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Physical Review D 56 (1997) 1239-1249    (hep-th/9701036 [PostScript.gz])

Title		Dynamical Symmetry Breaking in Fractal Space
Authors		Y. Nagatani
Abstract

We formulate field theories in fractal space and show the phase diagrams of the coupling versus the fractal dimension for the dynamical symmetry breaking. We first consider the 4-dimensional Gross-Neveu (GN) model in the (4-d)-dimensional randomized Cantor space where the fermions are restricted to a fractal space by the high potential barrier of Cantor fractal shape. By the statistical treatment of this potential, we obtain an effective action depending on the fractal dimension. Solving the 1/N leading Schwinger-Dyson (SD) equation, we get the phase diagram of dynamical symmetry breaking with a critical line similar to that of the d-dimensional (2 < d =< 4) GN model except for the system-size dependence. We also consider 4-dimensional QED with only the fermions formally compactified to d dimensions. Solving the ladder SD equation, we obtain the phase diagram of dynamical chiral symmetry breaking with a linear critical line, which is consistent with the known results for d=4 (the Maskawa-Nakajima case) and d=2 (the case with the external magnetic field).
HEP-SPIRES-SLAC 3483720
LANL hep-th/9701036

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Japan Physical Society Year Meeting'98 (Mar 30, 1998. at Toho Univ. Chiba)

Part		Elementary Particle
Title		Black Hole Baryogenesis
Number		30aC-3
Contents		(transparency in English)

• Title
• Introduction
• Electroweak Phase Structure
• Baryogenesis Scenarios
• B.H. Baryogenesis Scenarios
• Thick Wall B.H. Baryogenesis
• Thin Wall B.H. Baryogenesis
• Direct B.H. Baryogenesis
• Result
  • Figures
• Summary

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Japan Physical Society Year Meeting'97 (Mar 29, 1997. at Meijo Univ. Nagoya)

Part		Elementary Particle
Title		Dynamical Symmetry Breaking in Fractal Space
Number		29aYQ-10
Contents		(transparency in Japanese)

• Title Page
• 1. Introduction
• 2. Cantor Space
  • 2.2 Randomized Cantor Space
• 3. Fermions in Fractal Space
  • 3.2 Gross Neveu Model in Fractal Space
  • 3.3 Effective Action
• 4. 2-pt Function
  • 4.2 2-pt Function (Type II)
• 5. Phase Diagram
  • 5.2 Dependence on System Size
• 6. Summary

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Yukinori Nagatani, Yukawa Iinstitute for Theoretical Physics, Kyoto Univ.