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Minimal Supergravity, Inflation, and All That

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M. Ibe, K.-I. Izawa, Y. Shinbara, T.T. Yanagida

High Energy Physics - Phenomenology · Submitted 21 Feb 2006 · 22 references

Pith's reading: A large-cutoff supergravity model with new inflation and non-thermal leptogenesis can satisfy the spectral index, gravitino, dark matter, electroweak, and baryon asymmetry constraints in one parameter region.

T0 · AI review

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arXiv IDhep-ph/0602192 (version 2)
Pith IDWME5AFXB, Pith's permanent record of this paper and its review
CitationK.-I. Izawa, M. Ibe, T.T. Yanagida, Y. Shinbara. "Minimal Supergravity, Inflation, and All That." arXiv:hep-ph/0602192 (2006). https://pith.science/paper/WME5AFXB
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Claim paper
The paper

The paper claims

A large-cutoff supergravity model with new inflation and non-thermal leptogenesis can satisfy the spectral index, gravitino, dark matter, electroweak, and baryon asymmetry constraints in one parameter region.

The reading

The paper studies a model of the early universe built from a scalar field, the inflaton, whose potential is very flat near the origin. This flatness produces a long period of inflation and a specific small tilt in the spectrum of density fluctuations, the quantity called n_s. The model lives in a version of supergravity where the fundamental cutoff is about ten times the Planck scale. That choice makes the scalar superpartners heavy, around several TeV, and the gauginos light, which is what the authors need to satisfy electroweak symmetry breaking and dark matter constraints. After inflation, the inflaton oscillates and decays into pairs of heavy right-handed neutrinos. The neutrinos then decay into leptons and antileptons with a slight imbalance, creating the observed baryon asymmetry through leptogenesis. The temperature after reheating comes out around 10^6 GeV, low enough to avoid overproducing gravitinos, the spin-3/2 superpartners whose decays would otherwise spoil the predictions for light elements and structure formation. The gravitino mass in the model is several TeV to tens of TeV, also helping. The main result is an existence proof: the authors scan the small set of couplings and find a region, roughly g about 0.1, k about 0.01, and reheat temperature around 10^6 to 10^7 GeV, where all the constraints overlap. They do not derive the parameters from a deeper theory, and the success relies on assuming a maximal CP-violating phase in the neutrino decays. Still, the calculation is explicit and the consistency region is not extremely narrow.
Extended reading notes

Core claim

The paper's central assertion, from the abstract and Sec. 5, is that all the phenomenological requirements from cosmology and particle physics are satisfied in a certain parameter region of the large-cutoff theory. Qualified concretely, the n=4 new inflation model with g roughly 0.1, k roughly 0.01, and T_R around 10^6 to 10^7 GeV yields n_s consistent with 0.95 plus or minus 0.02, a gravitino mass above 4 TeV that avoids overproduction, and a non-thermal leptogenesis baryon asymmetry matching the WMAP value.

Load-bearing premise

The load-bearing premise is the large-cutoff hypothesis taken from the same authors' Ref. [5]: the fundamental cutoff M* is about 10 M_G and the effective parameters tilde{g} and tilde{k} are about 0.01, which fixes g~0.1 and k~0.01 (Secs. 1 and 2). In addition, the vacuum-energy cancellation in Eq. (23) is assumed, setting the gravitino mass through W at the inflaton minimum. If either a large cutoff is not realized or the cancellation is not natural, the claimed consistency region disappears.

Original abstract

We consider an inflationary model in the hidden-sector broken supergravity with an effectively large cutoff. The inflaton decay into right-handed neutrinos naturally causes the observed baryon asymmetry of the universe with a reheating temperature low enough to avoid the gravitino overproduction. We emphasize that all the phenomenological requirements from cosmology and particle physics are satisfied in the large-cutoff theory.

The compiled record

The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.

Compiled by classifier-1.13-20260917 via OpenRouter, question bank abstract-p1-20260923, 2026-09-23: 1 request, 2,922 input tokens, $0.0001 reported.

What the abstract itself states, as probabilities: claims first 0.03 · states limitation 0.10 · human participants 0.01 · controlled comparison 0.02 · randomized assignment 0.01 · states quantitative result 0.08 · compares with prior results 0.08 · mentions code or data availability 0.01.

The abstract, sentence by sentence

arXiv listing abstract v2. Results and the main claim are underlined; .

We consider an inflationary model in the hidden-sector broken supergravity with an effectively large cutoff. The inflaton decay into right-handed neutrinos naturally causes the observed baryon asymmetry of the universe with a reheating temperature low enough to avoid the gravitino overproduction. We emphasize that all the phenomenological requirements from cosmology and particle physics are satisfied in the large-cutoff theory.

background contribution method result interpretation main claim

What the classifier reports for each sentence. The number is the probability it gave the label.
#sentencerolethe authors' own workstates the main conclusionstrength
s0 We consider an inflationary model in the hidden-sector broken supergravity with an effectively large cutoff. contribution 0.88 0.76 0.08 asserted 0.73
s1 The inflaton decay into right-handed neutrinos naturally causes the observed baryon asymmetry of the universe with a reheating temperature low enough to avoid the gravitino overproduction. result 0.95 0.67 0.49 asserted 0.97
s2 We emphasize that all the phenomenological requirements from cosmology and particle physics are satisfied in the large-cutoff theory. result 0.55 0.66 0.57 asserted 1.00

What kind of paper the classifier reports this is: theoretical result 1.00 · evidence from argument 0.63.

What was examined, and what was not

sources read
  • arXiv listing abstract v2
not examined
  • full text
  • figures and tables
  • references and citing sentences
  • relations to other papers
levels run
  • P abstract
not run
  • S sections
  • T body sentences
  • C citations
  • R cross-paper relations

Every quoted sentence on this record is the authors'. Every label is from Pith's closed vocabulary, with the probability shown beside it. Every number in the measurements table is the authors', checked by code. Record as JSON

Figures
Figure 1. The k dependence of the spectral index ns for n = 4. The red (solid) line corresponds to the e-fold number Ne=45, the green (dashed) line to Ne=50, and the blue (dash-dotted) line to Ne=55. For k = 0, ns ≃ 1 − 6/(2Ne + 3). which yields the value of the inflaton field at the end of inflation. The value ϕNe of the inflaton corresponding to the e-fold number Ne is given by Ne ≃ Z ϕNe ϕf dϕ V (ϕ) V ′ (ϕ) ≃ Z ϕNe ϕf dϕ v 4 −kv4ϕ − gn 2 n 2 −1 v 2ϕn−1 . (14) This leads to ϕ n−2 Ne ≃ kv22 n 2 −1 gn ( 1 + k(n − 2) 1 − k e Nek(n−2) − 1 )−1 . (15) Hence the spectr
Figure 2. The k dependence of the spectral index ns for n = 4. The shaded regions correspond to TR = 105 , 107 , 109GeV from below, and the lower lines for g = 0.1 and the upper lines for g = 0.01. 3 The gravitino mass In the previous section, we have confirmed that the new inflation model in the large-cutoff hypothesis is consistent with the cosmological observations. In this section, we discuss the gravitino problem under such an inflationary scenario. As considered in Ref.[13], we assume that the positive energy Λ4 SUSY of the SUSY breaking is dominantly canceled out by the negative energy…
Figure 3. The contours of the gravitino mass for n = 4 and TR = 4 × 106GeV. The dependence on the reheating temperature is very weak. The second equality holds for n = 4, where we have used Eq.(21) and omitted the weak dependence on k and TR. More precisely, by means of Eq.(19) and (22), the gravitino mass can be expressed as a function of g, k, and TR, although the dependence on TR is very weak, as can be seen from Eq.(19) and (22). The result is shown in Fig.3. For g < ∼ 0.2 and k < ∼ 0.035, the gravitino mass is larger than 4TeV, which may avoid the gravitino overproduction for a reheating
Figure 4. The contours of  nB s  /  nB s  0 for n = 4, TR = 4 × 106GeV, δef f = 1, sin β = 1 are plotted in red (solid) lines. The blue (dashed-dotted) lines correspond to the contours of gravitino mass. We note that the baryon asymmetry and the gravitino mass for different reheating temper￾atures can also be seen from Fig.4: The baryon asymmetry is proportional to the square of the reheating temperature T 2 R, since the coupling h is approximately proportional to the reheating temperature. As for the gravitino mass, its value is almost independent of TR, since v is almost indepen

Figures reproduced from arXiv:hep-ph/0602192 by the authors.

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References
How the literature uses it

4 arXiv papers cite this in 8 sentences

Each citing sentence is taken from the citing paper's LaTeX source and typed by Pith's classifier. A label appears at probability 0.8 or more (0.95 for support), a contest at 0.7 or more; the quoted words are the citing authors'. How each label was checked · JSON

Papers citing it · 7 sentences without a confident label

Cites it as background 1 paper

Discussion

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