Textures and semi-local strings in supersymmetric hybrid inflation

Battye, Richard A.; Garbrecht, Björn; Pilaftsis, Apostolos

doi:10.1088/1475-7516/2008/09/020

Cited by 8 publications

(12 citation statements)

References 64 publications

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“…These spots could be the result of some yet not fully understood physical process. For the cold spot , lots of theories already exist which try to explain its origin by second‐order gravitational effects (Tomita 2005; Tomita & Inoue 2008), a finite universe model (Adler, Björken & Overduin 2006), large dust‐filled voids (Inoue & Silk 2006, 2007; Rudnick, Brown & Williams 2007; Granett, Neyrinck & Szapudi 2008), cosmic textures (Cruz et al 2007), non‐Gaussian modulation (Naselsky et al 2007), topological defects (Battye, Garbrecht & Pilaftsis 2008), textures in a brane world model (Cembranos et al 2008) or an asymptotically flat Lemaître–Tolman–Bondi model (Garcia‐Bellido & Haugbolle 2008; Masina & Notari 2009).…”

Section: Resultsmentioning

confidence: 99%

Non-Gaussian signatures in the five-yearWMAPdata as identified with isotropic scaling indices

Rossmanith

Räth

Banday

et al. 2009

Monthly Notices of the Royal Astronomical Society

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We continue the analysis of non‐Gaussianities in the cosmic microwave background by means of the scaling index method by applying this method on the single Q, V, W bands and the co‐added VW band of the five‐year data of the Wilkinson Microwave Anisotropy Probe. We compare each of the results with 1000 Monte Carlo simulations mimicking the Gaussian properties of the best fitting Λ cold dark matter model. Based on the scaling indices, scale‐dependent empirical probability distributions, moments of these distributions and χ2 combinations of them are calculated, obtaining similar results as in the former analysis of the three‐year data: we derive evidence for non‐Gaussianity with a probability of up to 97.3 per cent for the mean when regarding the KQ75‐masked full sky and summing up over all considered length‐scales by means of a diagonal χ2 statistics. Looking at only the northern or southern hemisphere of the galactic coordinate system, we obtain up to 98.5 or 96.6 per cent, respectively. For the standard deviation, these results appear as 95.6 per cent for the full sky (99.7 per cent north, 89.4 per cent south) and for a χ2 combination of both measurements as 97.4 per cent (99.1 per cent north, 95.5 per cent south). We obtain larger deviations from Gaussianity when looking at separate scale lengths. By performing an analysis of rotated hemispheres, we detect an obvious asymmetry in the data. In addition to these investigations, we present a method of filling the mask with Gaussian noise to eliminate boundary effects caused by the mask. With the help of this technique, we identify several local features on the map, of which the most significant one turns out to be the well‐known cold spot. When excluding all these spots from the analysis, the deviation from Gaussianity increases, which shows that the discovered local anomalies are not the reason of the global detection of non‐Gaussianity, but actually were damping the deviations on average. Our analyses per band and per year suggest, however, that it is very unlikely that the detected anomalies are due to foreground effects.

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Section: Resultsmentioning

confidence: 99%

Non-Gaussian signatures in the five-yearWMAPdata as identified with isotropic scaling indices

Rossmanith

Räth

Banday

et al. 2009

Monthly Notices of the Royal Astronomical Society

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“…Our Majorana scalar-field formalism can also be used to study more general scalar potentials which are not constrained by the U(1) Y hypercharge symmetry and can realize a maximal number of 15 distinct symmetries. Such 2HDM potentials may not be directly related to the observable SM gauge group, but may form an independent hidden sector, as it is, for example, the case in supersymmetric theories of hybrid inflation [44,45]. The formation of topological defects, such as domain walls, cosmic strings, monopoles, or textures, through the spontaneous symmetry breaking of global, local or discrete symmetries may have important implications for the analysis of the cosmological data.…”

Section: Discussionmentioning

confidence: 99%

“…In this section we discuss the application of our Majorana scalar-field formalism to 2HDM potentials which are not restricted by the U(1) Y hypercharge group. Even though such potentials may not be viable within the context of the SM, they may still be realized in models describing cosmological inflation [44,45]. Furthermore, we classify all possible 15 symmetries that may occur in a general U(1) Y -violating 2HDM potential, within the 6dimensional bilinear field space.…”

Section: The U(1) Y -Violating 2hdmmentioning

confidence: 99%

“…After having identified the precise nature of the topological solution, we then study quantitatively their spatial profile, as a function of the potential parameters. The results of our analysis may be used in future studies to derive cosmological constraints on the 2HDM, or on inflationary models with related SU(2) group structure [44,45,46,47,48].…”

Section: Introductionmentioning

confidence: 99%

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Vacuum topology of the two Higgs doublet model

Battye

Brawn

Pilaftsis

2011

J. High Energ. Phys.

Self Cite

115

134

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We perform a systematic study of generic accidental Higgs-family and CP symmetries that could occur in the two-Higgs-doublet-model potential, based on a Majorana scalar-field formalism which realizes a subgroup of GL(8, C). We derive the general conditions of convexity and stability of the scalar potential and present analytical solutions for two non-zero neutral vacuum expectation values of the Higgs doublets for a typical set of six symmetries, in terms of the gauge-invariant parameters of the theory. By means of a homotopy-group analysis, we identify the topological defects associated with the spontaneous symmetry breaking of each symmetry, as well as the massless Goldstone bosons emerging from the breaking of the continuous symmetries. We find the existence of domain walls from the breaking of Z 2 , CP1 and CP2 discrete symmetries, vortices in models with broken U(1) PQ and CP3 symmetries and a global monopole in the SO(3) HF -broken model. The spatial profile of the topological defect solutions is studied in detail, as functions of the potential parameters of the two-Higgs doublet model. The application of our Majorana scalar-field formalism in studying more general scalar potentials that are not constrained by the U(1) Y hypercharge symmetry is discussed. In particular, the same formalism may be used to properly identify seven additional symmetries that may take place in a U(1) Y -invariant scalar potential.

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“…We note that we obtain a considerably smaller estimate than the f N L = −1000 in ref. [11] for several reasons, including the extension of our analysis over lower multipole ranges relevant for WMAP, a more careful comparison with f N L estimators used in the literature, and a lower normalisation of the string spectrum derived for Nambu strings [5], rather than that obtained from field theory simulations [6]. Nevertheless, as we shall discuss, our estimate contains many uncertainties and more detailed and accurate forecasts are the subject of ongoing work [12].…”

Section: Discussionmentioning

confidence: 99%

Cosmic string power spectrum, bispectrum, and trispectrum

Regan

Shellard

2010

Phys. Rev. D

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We use analytic calculations of the post-recombination gravitational effects of cosmic strings to estimate the resulting CMB power spectrum, bispectrum and trispectrum. We place a particular emphasis on multipole regimes relevant for forthcoming CMB experiments, notably the Planck satellite. These calculations use a flat sky approximation, generalising previous work by integrating string contributions from last scattering to the present day, finding the dominant contributions to the correlators for multipoles l > 50. We find a well-behaved shape for the string bispectrum (without divergences) which is easily distinguishable from inflationary bispectra which possess significant acoustic peaks. We estimate that the nonlinearity parameter characterising the bispectrum is approximately fNL ∼ −20 (given present string constraints from the CMB power spectrum. We also apply these unequal time correlator methods to calculate the trispectrum for parrallelogram configurations, again valid over a large range of angular scales relevant for WMAP and Planck, as well as on very small angular scales. We find that, unlike the bispectrum which is suppressed by symmetry considerations, the trispectrum for cosmic strings is large. Our current estimate for the trispectrum parameter is τNL ∼ 10 4 , which may provide one of the strongest constraints on the string model as observational estimates for the trispectrum improve.

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Textures and semi-local strings in supersymmetric hybrid inflation

Cited by 8 publications

References 64 publications

Non-Gaussian signatures in the five-yearWMAPdata as identified with isotropic scaling indices

Non-Gaussian signatures in the five-yearWMAPdata as identified with isotropic scaling indices

Vacuum topology of the two Higgs doublet model

Cosmic string power spectrum, bispectrum, and trispectrum

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