String Landscape and Supernovae Ia L. Clavelli, U of Alabama (with - - PowerPoint PPT Presentation

String Landscape and Supernovae Ia

• L. Clavelli, U of Alabama

(with Peter Biermann, UA, Bonn, Karlsruhe ...) Susy11, Fermilab, August 2011 Should we take the string landscape seriously?

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First Theory House at Fermilab, 1969

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A Bicuspid Landscape?

• 4
• 2

2 4 Φ 175 140 105 70 35 log10V(Φ)

≈ time constant for volume expansion of the universe: τ =

1

√

24πGNǫ = 5.6 · 109yr

• 2.3·10−3eV

ǫ

1/2

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a supersymmetric universe

a world of greatly weakened Pauli Principle →

p1 p2 p3 p4 (a) p1 p2 p4 p3 (b)

f + f → ˜ f + ˜ f

SUSY US ε vac energy density ε = 3560 MeV/m3

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Phase transitions could be accelerated in dense matter

A.S. Gorsky and V.G. Kiselev,

• Phys. Lett. B304,214 (1999)

Proven as yet only in lower dimensions

Could susy be nature’s way to release the energy stored in the Pauli towers?

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SUSY US ε vac energy density ε = 3560 MeV/m3

Starting point: Coleman-DeLuccia formula (1980)

d2P dtd3r = ACe−B(vac)

B(vac) = 27π2S4

2 ¯ h c ǫ3

B(matter) =

27π2S4 2 ¯ h c (ǫ+∆ρ)3

Fermi Gas Model: ∆ρ = 0.02ρ B(matter) = (ρc

ρ )3

AC =

1 τ0V0

Φ V(Φ) ε+ρ ρS US SUSY 6

Primary features of SN Ia:

• 1. No hydrogen in emission
• 2. homogeneity: standardizable candles
• 3. light curve dominated by Ni56 production and decay
• 4. Rate: About one per century per galaxy

(more in star-burst galaxies => short time scale for SN Ia production)

• 5. but also observed in old galaxies => range of time scales

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main sequence star accreting onto a white dwarf (single degenerate scenario) astronomers have spent thousands of man-years explaining how such accretion disks could cause Supernovae Ia.

But they don’t!

Gilfanov and Bogdan (Nature 2010): 95% of SN Ia don’t occur like this. (similar conclusion: Bianco et al. ArXiv:1106.4008

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The Double Degenerate Scenario (two white dwarfs accreting from one to the other)

2008 review by Hillebrandt and Niemeyer: “Besides the lack of convincing direct observational ev- idence for sufficiently many appropriate binary systems, the homogeneity of ‘typical’ SNe Ia may be an argument against this class of progenitors. It is not easy to see how the merging of two white dwarfs of (likely) different mass, composition, and angular momentum with differ- ent impact parameters, etc, will always lead to the same burning conditions and, therefore, the production of a nearly equal amount of 56Ni.”

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some of Chandra’s white dwarfs

.4 .8 1.2 1.6 2 r/rE 10 10 9 10 8 10 7 10 6 10 5 10 4 10 ρ .27 .51 .81 1.1 1.24 1.33 1.37

density distribution in seven typical white dwarfs (masses given relative to solar mass)

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Basic Assumption: In any object containing heavy nuclei (above He) The probability per unit time per unit volume to convert to exact susy is:

d2P dtd3r = 1 τ0V0e−(ρc

ρ )3

− 1

N dN dt = 1 τ = dP dt = Vc τ0V0

Vc ≡

• d3re−(ρc

ρ )3

Best fit values: ρc ≈ 107 g/cc τ0 ≈ 0.5 · 109 yr For preferred value of ρc choose V0 to be the maximum Vc of naturally occuring objects. Then τ0 is the minimum lifetime.

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.3 .6 .9 1.2 1.5 M/M0 3 10 2 10 1 10 10

• 1

10 τ/τ0 106 107 108.8 108

dNWD dt

= −1

τ The τ/τ0 as a function of mass for critical densities

• f 106, 107, 108, and 6.3 · 108 g/cc.

For approprate choice of ρc, the narrowness of the SN Ia distribution is naturally explained.

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7 10 8 10 9 10 ρc (g/cc) 1 10 10

• 1

10

• 2

10 τ0 (Gyr)

Supernova Ia rate: dNSNIa

dt

= NWD

G(ρc) τ0

G(ρc) =

dM

1 NWD dNWD dM 1 V0

• d3xe−(ρc/ρ)3

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10 1 10 2 10 2 10 1 10 10

• 1

10

• 2

10

• 3

10 dN/dτ (Gyr)-1 τ (Gyr)

Distribution of white dwarf lifetimes relative to minimum lifetime, τ0 ≈ 5 · 108yr

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The Black Hole Gap

Evidence abounds for black holes of Mass > 105 Msolar and for Masses < 100 Msolar

but not for intermediate masses. Schwarzschild radius: RS = 2 GN M/c2 = 4.64 10−4 RE M/M⊙ Maximum density before becoming black hole: ρmax =

3 M 4 π RS3 = ρWD

 105 M⊙

M

 

2

(nominal white dwarf density ρWD = 3 M⊙

4π R3

E

)

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Results of two parameter model:

• threshold in black hole spectrum at ≈ 105 M⊙
• extra energy for supernovae explosions
• collapse of isolated white dwarfs
• narrow distribution of progenitor masses
• short WD lifetime at optimum mass
• SN rate correctly fit

Predictions:

• low mass black holes below Chandra mass 1.4 M⊙
• our world should be a broken susy universe (LHC)
• eventual vacuum decay of entire universe to exact susy
• n time scale τ ≈ =

1

√24πGNǫi = 5.6 · 109yr

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