Typical Mass Scale Research Articles

Emergence of R4-terms in M-theory

It has been recently suggested that the strong Emergence Proposal is realized in M-theory limits by integrating out all light towers of states with a typical mass scale not larger than the species scale, i.e. the eleventh dimensional Planck mass. Within the BPS sector, these are transverse M2- and M5-branes, that can be wrapped and particle-like, carrying Kaluza-Klein momentum along the compact directions. We provide additional evidence for this picture by revisiting and investigating further the computation of R4-interactions in M-theory à la Green-Gutperle-Vanhove. A central aspect is a novel UV-regularization of Schwinger-like integrals, whose actual meaning and power we clarify by first applying it to string perturbation theory. We consider then toroidal compactifications of M-theory and provide evidence that integrating out all light towers of states via Schwinger-like integrals thus regularized yields the complete result for R4-interactions. In particular, this includes terms that are tree-level, one-loop and space-time instanton corrections from the weakly coupled point of view. Finally, we comment on the conceptual difference of our approach to earlier closely related work by Kiritsis-Pioline and Obers-Pioline, leading to a correspondence between two types of constrained Eisenstein series.

Demystifying the Emergence Proposal

We revisit the Emergence Proposal in the vector multiplet moduli space of type IIA N = 2 supersymmetric string vacua in four dimensions, for which the string tree-level prepotential and the string one-loop correction are exactly known via mirror symmetry. We argue that there exists an exact notion of emergence, according to which these four-dimensional couplings can be computed exactly in any asymptotic limit in field space. In such limits, a perturbative quantum gravity theory emerges, whose fundamental degrees of freedom include all complete infinite towers of states with typical mass scale not larger than the species scale. For a decompactification limit, this picture is closely related to and in fact motivated by the computation of Gopakumar-Vafa invariants. In addition, in the same limit our results suggest that the emergent theory will also contain asymptotically tensionless wrapped NS5-branes.

Emergent M-theory limit

It has been recently proposed that at each infinite distance limit in the moduli space of quantum gravity a perturbative description emerges with fundamental degrees of freedom given by those infinite towers of states whose typical mass scale is parametrically not larger than the ultraviolet cutoff, identified with the species scale. This proposal is applied to the familiar ten-dimensional type IIA and IIB superstring theories, when considering the limit of infinite string coupling. For type IIB, the light towers of states are given by excitations of the D1-brane, as expected from self-duality. Instead, for type IIA at strong coupling, which is dual to M-theory on S1, we make the observation that the emergent degrees of freedom are bound states of transversal M2- and M5-branes with Kaluza-Klein momentum along the circle. We speculate on the interpretation of the necessity of including all these states for a putative quantum formulation of M-theory. Published by the American Physical Society 2024

A Census of Protostellar Outflows in Nearby Molecular Clouds

Abstract We adopt the deep learning method casi-3d (Convolutional Approach to Structure Identification-3D) to systemically identify protostellar outflows in 12CO and 13CO observations of the nearby molecular clouds, Ophiuchus, Taurus, Perseus, and Orion. The total outflow masses are 267 M ⊙, 795 M ⊙, 1305 M ⊙, and 6332 M ⊙ for Ophiuchus, Taurus, Perseus, and Orion, respectively. We show the outflow mass in each cloud is linearly proportional to the total number of young stellar objects. The estimated total 3D deprojected outflow energies are 9 × 1045 erg, 6 × 1046 erg, 1.2 × 1047 erg, and 6 × 1047 erg for Ophiuchus, Taurus, Perseus, and Orion, respectively. The energy associated with outflows is sufficient to offset turbulent dissipation at the current epoch for all four clouds. All clouds also exhibit a break point in the spatial power spectrum of the outflow prediction map, which likely corresponds to the typical outflow mass and energy injection scale.

Effective field theories and inflationary magnetogenesis

The effective approach is applied to the analysis of inflationary magnetogenesis. Rather than assuming a particular underlying description, all the generally covariant terms potentially appearing with four space-time derivatives in the effective action have been included and weighted by inflaton-dependent couplings. The higher derivatives are suppressed by the negative powers of a typical mass scale whose specific values ultimately depend on the tensor to scalar ratio. During a quasi-de Sitter stage the corresponding corrections always lead to an asymmetry between the hypermagnetic and the hyperelectric susceptibilities. After presenting a general method for the estimate of the gauge power spectra, the obtained results are illustrated for generic models and also in the case of some non-generic scenarios where either the inflaton has some extra symmetry or the higher-order terms are potentially dominant.

Giant molecular cloud catalogues for PHANGS-ALMA: methods and initial results

ABSTRACTWe present improved methods for segmenting CO emission from galaxies into individual molecular clouds, providing an update to the cprops algorithms presented by Rosolowsky & Leroy. The new code enables both homogenization of the noise and spatial resolution among data, which allows for rigorous comparative analysis. The code also models the completeness of the data via false source injection and includes an updated segmentation approach to better deal with blended emission. These improved algorithms are implemented in a publicly available Python package, pycprops. We apply these methods to 10 of the nearest galaxies in the PHANGS-ALMA survey, cataloguing CO emission at a common 90 pc resolution and a matched noise level. We measure the properties of 4986 individual clouds identified in these targets. We investigate the scaling relations among cloud properties and the cloud mass distributions in each galaxy. The physical properties of clouds vary among galaxies, both as a function of galactocentric radius and as a function of dynamical environment. Overall, the clouds in our target galaxies are well-described by approximate energy equipartition, although clouds in stellar bars and galaxy centres show elevated line widths and virial parameters. The mass distribution of clouds in spiral arms has a typical mass scale that is 2.5× larger than interarm clouds and spiral arms clouds show slightly lower median virial parameters compared to interarm clouds (1.2 versus 1.4).

The gravitational waves from the collapsing domain walls in the complex singlet model

We study the CP domain walls and the consequent gravitational waves induced by the spontaneous breaking of the CP symmetry in the complex singlet extension to the Standard Model. We impose the constraints from the unitarity, stability and the global minimal of the vacuum solutions on the model parameter space. The CP domain wall profiles and tensions are obtained by numerically solving the relevant field equations. The explicit CP violation terms are then introduced to the potential as biased terms to make the domain walls unstable and collapse, The BBN bound on the magnitude of the energy bias is taken into account. To achieve sufficiently strong gravitational wave signals, the domain wall tension σ is required to be at least σ/TeV3∼ mathcal{O} (103). We find that the gravitational wave spectrum can be probed in the future SKA and/or DECIGO programs, when the typical mass scale is at least ∼ mathcal{O} (10) TeV and the explicit CP violation terms are as small as mathcal{O} (10−24)− mathcal{O} (10−23). The gravitational waves from collapsing domain walls thus provide a complementarity to the probe of extremely small CP violation at high-energy scale.

Lattice-friendly gauge completion of a composite Higgs with top partners

We give an explicit example of a composite Higgs model with a pseudo-Nambu-Goldstone Higgs in which the top Yukawa coupling is generated via the partial compositeness mechanism. This mechanism requires composite top partners which are relatively light compared to the typical mass scale of the strongly coupled theory. While most studies of the phenomenology of such models have focused on a bottom-up approach with a minimal effective theory, a top-down approach suggests that the theory should contain a limit in which an unbroken global chiral symmetry protects the mass of the top partners, and the spectrum of the partners satisfies ‘t Hooft matching conditions. We find that the relatively light fermions and pseudo-Goldstone bosons fall into complete multiplets of a large approximate global symmetry, and that the spectrum of particles lighter than a few TeV is non-minimal. Our example illustrates the likely features of a such a composite Higgs theory and also serves as an example of a non-chiral theory with a possible solution to the ‘t Hooft matching conditions. We find in this example that for some low-energy parameters in the effective theory the top partners can decay into high-multiplicity final states, which could be difficult for the Large Hadron Collider (LHC) to constrain. This may potentially allow for the top partners to be lighter than those in more minimal models.

The FMOS-COSMOS Survey of Star-forming Galaxies at Z ∼ 1.6. V: Properties of Dark Matter Halos Containing Hα Emitting Galaxies

Abstract We study the properties of dark matter halos that contain star-forming galaxies at 1.43 ≤ z ≤ 1.74, using the FMOS-COSMOS survey. The sample consists of 516 objects with a detection of the Hα emission line, which represent the star forming population at this epoch, having a stellar mass range of 109.57 ≤ M */M ⊙ ≲ 1011.4 and a star-formation rate range of 15 ≲ SFR/(M ⊙ yr−1) ≲ 600. We measure the projected two-point correlation function while carefully taking into account observational biases, and find a significant clustering amplitude at scales of 0.04–10 h −1 cMpc, with a correlation length and a bias . We interpret our clustering measurement using a halo occupation distribution model. The sample galaxies appear to reside in halos with mass on average, which will likely become present-day halos of mass M h (z = 0) ∼ 2 × 1013 h −1 M ⊙, equivalent to the typical halo mass scale of galaxy groups. We then confirm the decline of the stellar-to-halo mass ratio at M h < 1012 M ⊙, finding M */M h ≈ 5 × 10−3 at M h = 7. 5 × 1011 M ⊙, which is lower by a factor of 2–4 than those measured at higher masses (M h ∼ 1012–13 M ⊙). Finally, we use our results to illustrate the future capabilities of Subaru’s Prime-Focus Spectrograph, a next-generation instrument that will provide strong constraints on the galaxy-formation scenario by obtaining precise measurements of galaxy clustering at z > 1.

Higher-order Wilson coefficients for c → u transitions in the standard model

The standard theoretical framework to deal with weak decays of heavy mesons is the so-called weak effective Hamiltonian. It involves the short-distance Wilson coefficients, which depend on the renormalisation scale $\mu$. For specific calculations one has to evolve the Wilson coefficients down from the electroweak scale $\mu=M_W$ to the typical mass scale of the decay under consideration. This is done by solving a renormalisation group equation for the effective operator basis. In this paper the results of a consistent two-step running of the $c \to u \,\ell^+\ell^-$ Wilson coefficients for dimension-6 operators are presented. This running involves the intermediate scale $\mu=m_b$ (with $M_W > m_b > m_c$) where the bottom quark is integrated out. The matching coefficients and anomalous dimensions are taken to the required order by generalizing and extending results from $b \to s$ or $s \to d$ transitions available in the literature.

The XXL Survey

The XXL Survey is the largest homogeneous and contiguous survey carried out with XMM-Newton. Covering an area of 50 square degrees distributed over two fields, it primarily investigates the large-scale structures of the Universe using the distribution of galaxy clusters and active galactic nuclei as tracers of the matter distribution. Given its depth and sky coverage, XXL is particularly suited to systematically unveiling the clustering of X-ray clusters and to identifying superstructures in a homogeneous X-ray sample down to the typical mass scale of a local massive cluster. A friends-of-friends algorithm in three-dimensional physical space was run to identify large-scale structures. In this paper we report the discovery of the highest redshift supercluster of galaxies found in the XXL Survey. We describe the X-ray properties of the clusters members of the structure and the optical follow-up. The newly discovered supercluster is composed of six clusters of galaxies at a median redshift z around 0.43 and distributed across approximately 30 by 15 arc minutes (10 by 5 Mpc on sky) on the sky. This structure is very compact with all the clusters residing in one XMM pointing; for this reason this is the first supercluster discovered with the XXL Survey. Spectroscopic follow-up with WHT (William Herschel Telescope) and NTT (New Technology Telescope) confirmed a median redshift of z = 0.43. An estimate of the X-ray mass and luminosity of this supercluster and of its total gas mass put XLSSC-e at the average mass range of superclusters; its appearance, with two members of equal size, is quite unusual with respect to other superclusters and provides a unique view of the formation process of a massive structure.

Reevaluation of Higgs-mediated [formula omitted] transition in the MSSM

In this Letter, we reevaluated the Higgs-mediated contribution to μ→eγ, μ→3e, and μ–e conversion in nuclei in the MSSM, assuming left-handed sleptons have flavor-mixing mass terms. Contrary to previous works, it is found that Barr–Zee diagrams including top quark give dominant contribution to μ→eγ, and those including bottom quark and tau lepton are also non-negligible only when tanβ is large. As a result, the Higgs-mediated contribution dominates over the gaugino-mediated contribution at one-loop level in μ→eγ when MSUSY/mA0≳50, irrespectively of tanβ as far as tanβ is not large. Here, MSUSY and mA0 are a typical mass scale of the SUSY particles and the CP-odd Higgs boson mass, respectively. Ratio of branching ratios for μ→eγ and μ–e conversion in nuclei is also evaluated by including both the gaugino- and Higgs-mediated contributions to the processes. It is found that the ratio is sensitive to tanβ and MSUSY/mA0 when MSUSY/mA0∼(10–50) and tanβ≳10.

Infrared dynamics of minimal walking technicolor

We study the gauge sector of Minimal Walking Technicolor, which is an SU(2) gauge theory with nf=2 flavors of Wilson fermions in the adjoint representation. Numerical simulations are performed on lattices Nt x Ns^3, with Ns ranging from 8 to 16 and Nt=2Ns, at fixed \beta=2.25, and varying the fermion bare mass m0, so that our numerical results cover the full range of fermion masses from the quenched region to the chiral limit. We present results for the string tension and the glueball spectrum. A comparison of mesonic and gluonic observables leads to the conclusion that the infrared dynamics is given by an SU(2) pure Yang-Mills theory with a typical energy scale for the spectrum sliding to zero with the fermion mass. The typical mesonic mass scale is proportional to, and much larger than this gluonic scale. Our findings are compatible with a scenario in which the massless theory is conformal in the infrared. An analysis of the scaling of the string tension with the fermion mass towards the massless limit allows us to extract the chiral condensate anomalous dimension \gamma*, which is found to be \gamma*=0.22+-0.06.

Reionization: A probe for the stellar population and the physics of the early universe

We calculate the reionization history for different models of the stellar population and explore the effects of primordial magnetic fields, dark matter decay and dark matter annihilation on reionization. We find that stellar populations based on a Scalo-type initial mass function for Population II stars can be ruled out as sole sources for reionization, unless star formation efficiencies of more than 10% or very high photon escape fractions from the parental halo are adopted. When considering primordial magnetic fields, we find that the additional heat injection from ambipolar diffusion and decaying MHD turbulence has a significant impact on the thermal evolution and the ionization history of the post-recombination universe and on structure formation. The magnetic Jeans mass changes the typical mass scale of the star-forming halos, and depending on the adopted stellar model we derive upper limits to the magnetic field strength between 0.7 and 5 nG (comoving). For dark matter annihilation, we find an upper limit to the thermally averaged mass-weighted cross section of $⟨\ensuremath{\sigma}v⟩/{m}_{\mathrm{DM}}\ensuremath{\le}{10}^{\ensuremath{-}33}\text{ }\text{ }{\mathrm{cm}}^{3}/\mathrm{s}/\mathrm{eV}$. For dark matter decay, our calculations yield a lower limit to the lifetime of dark matter particles of $\ensuremath{\tau}\ensuremath{\ge}3\ifmmode\times\else\texttimes\fi{}{10}^{23}\text{ }\text{ }\mathrm{s}$. These limits are in agreement with constraints from recombination and provide an independent confirmation at a much later epoch.

The evolution of dark matter halo properties in clusters, filaments, sheets and voids

We use a series of high-resolution N-body simulations of the concordance cosmology to investigate the redshift evolution since z = 1 of the properties and alignment with the large-scale structure (LSS) of haloes in clusters, filaments, sheets and voids. We find that (i) once a rescal-ing of the halo mass with M * (z), the typical mass scale collapsing at redshift z, is performed, there is no further significant redshift dependence in the halo properties; (ii) the environment influences the halo shape and formation time at all investigated redshifts for haloes with masses M ≤ M * and (iii) there is a significant alignment of both spin and shape of haloes with filaments and sheets. In detail, at all redshifts up to z = 1: (a) haloes with masses below ∼ M * tend to be more oblate when located in clusters than in the other environments; this trend is reversed at higher masses: above about M * , haloes in clusters are typically more prolate than similar massive haloes in sheets, filaments and voids. (b) The haloes with M ≥ M * in filaments spin more rapidly than similar mass haloes in clusters; haloes in voids have the lowest median spin parameters. (c) Haloes with M ≤ M * tend to be younger in voids and older in clusters. (d) In sheets, halo spin vectors tend to lie preferentially within the sheet plane independent of halo mass; in filaments, instead, haloes with M ≤ M * tend to spin parallel to the filament and higher mass haloes perpendicular to it. For halo masses M ≥ M * , the major axis of haloes in filaments and sheets is strongly aligned with the host filament or the sheet plane, respectively. Such halo-LSS alignments may be of importance in weak lensing analyses of cosmic shear. A question that is opened by our study is why, in the 0 < z < 1 redshift regime that we have investigated, the mass scale for gravitational collapse, M * , sets roughly the threshold below which the LSS environment either begins to affect, or reverses, fundamental properties of dark matter haloes.

Three-loop corrections to the lightest Higgs scalar boson mass in supersymmetry

I evaluate the largest three-loop corrections to the mass of the lightest Higgs scalar boson in the minimal supersymmetric standard model in a mass-independent renormalization scheme, using effective field theory and renormalization group methods. The contributions found here are those that depend only on strong and Yukawa interactions and on the leading and next-to-leading logarithms of the ratio of a typical superpartner mass scale to the top-quark mass. The approximation assumes that all superpartners and the other Higgs bosons can be treated as much heavier than the top quark, but does not assume their degeneracy. I also discuss the consistent addition of the three-loop corrections to a complete two-loop calculation.

Clustering of the IR Background Light withSpitzer: Contribution from Resolved Sources

We describe the angular power spectrum of resolved sources at 3.6 μm (L band) in Spitzer imaging data of the GOODS HDF-N, the GOODS CDF-S, and the NDWFS Bootes field in several source magnitude bins. We also measure angular power spectra of resolved sources in the Bootes field at Ks and J bands using ground-based IR imaging data. In the three bands, J, Ks, and L, we detect the clustering of galaxies on top of the shot-noise power spectrum at multipoles between l ~ 102 and 105. The angular power spectra range from the large, linear scales to small, nonlinear scales of galaxy clustering, and in some magnitude ranges show departure from a power-law clustering spectrum. We consider a halo model to describe clustering measurements and to establish the halo occupation number parameters of IR bright galaxies at redshifts around one. The typical halo mass scale at which two or more IR galaxies with L-band Vega magnitude between 17 and 19 are found in the same halo is between 9 × 1011 and 7 × 1012 M☉ at the 1 σ confidence level; this is consistent with the previous halo mass estimates for bright, red galaxies at z ~ 1. We also extend our clustering results and completeness-corrected faint-source number counts in GOODS fields to understand the underlying nature of unresolved sources responsible for IR background (IRB) anisotropies that were detected in deep Spitzer images. While these unresolved fluctuations were measured at subarcminute angular scales, if a high-redshift diffuse component associated with first galaxies exists in the IRB, then it's clustering properties are best studied with shallow, wide-field images that allow a measurement of the clustering spectrum from a few degrees to arcminute angular scales.

An algorithm for the high-energy expansion of multi-loop diagrams to next-to-leading logarithmic accuracy

We present an algorithm to compute arbitrary multi-loop massive Feynman diagrams in the region where the typical energy scale Q is much larger than the typical mass scale M, i.e., Q ≫ M , while various different energy and mass parameters may be present. In this region we perform an asymptotic expansion and, using sector decomposition, we extract the leading contributions resulting from ultraviolet and mass singularities, which consist of large logarithms ln ( Q 2 / M 2 ) and 1 / ɛ poles in D = 4 − 2 ɛ dimensions. To next-to-leading accuracy, at L loops all terms of the form α L ɛ − k ln j ( Q 2 / M 2 ) with j + k = 2 L and j + k = 2 L − 1 are taken into account. This algorithm permits, in particular, to compute higher-order next-to-leading logarithmic electroweak corrections for processes involving various kinematical invariants of the order of hundreds of GeV and masses M W ∼ M Z ∼ M H ∼ m t of the order of the electroweak scale, in the approximation where the masses of the light fermions are neglected.

The Mass Spectrum of Metal‐free Stars Resulting from Photodissociation Feedback: A Scenario for the Formation of Low‐Mass Population III Stars

The initial mass function (IMF) of metal-free stars that form in the initial starburst of massive (virial temperatures >10^4K) metal-free protogalaxies is studied. In particular, we focus on the effect of H2 photodissociation by pre-existing stars on the fragmentation mass scale, presumedly determined by the Jeans mass at the end of the initial free-fall phase, i.e., at the so-called ``loitering phase,'' characterized by the local temperature minimum. Photodissociation diminishes the Jeans mass at the loitering phase, thereby reducing the fragmentation mass scale of primordial clouds. Thus, in a given cloud, far ultraviolet (FUV) radiation from the first star, which is supposedly very massive (about 10^3Msun), reduces the mass scale for subsequent fragmentation. Through a series of similar processes the IMF for metal-free stars is established. If FUV radiation exceeds a threshold level, the star-forming clumps collapse solely through atomic cooling. Correspondingly, the fragmentation scale drops discontinuously from a few time 10Msun to sub-solar scales. In compact clouds (>1.6kpc for clouds of gas mass 10^8Msun), this level of radiation field is attained, and sub-solar mass stars are formed even in a metal-free environment. Consequently, the IMF becomes bi-modal, with peaks at a few tenths of Msun and a few times 10Msun. The high-mass portion of the IMF is found to be a very steep function of the stellar mass, xi_high(m) being proportinal to m^{-5}. Therefore, the typical mass scale of metal-free stars is significantly smaller than that of the very first stars. Also we study the thermal instability in collapsing primordial prestellar clumps, and discuss why the thermal instability occuring during the three-body H2 formation does not appear to manifest itself in causing further fragmentation of such clumps.

Isoperimetric inequality for higher-dimensional black holes

The initial data sets for the five-dimensional Einstein equation have been examined. The system is designed such that the black hole $(\ensuremath{\simeq}{S}^{3})$ or the black ring $(\ensuremath{\simeq}{S}^{2}\ifmmode\times\else\texttimes\fi{}{S}^{1})$ can be found. We have found that the typical length of the horizon can become arbitrarily large but the area of characteristic closed two-dimensional submanifold of the horizon is bounded above by the typical mass scale. We conjecture that the isoperimetric inequality for black holes in n-dimensional space is given by ${V}_{n\ensuremath{-}2}\ensuremath{\lesssim}GM,$ where ${V}_{n\ensuremath{-}2}$ denotes the volume of a typical closed (n-2)-section of the horizon and M is typical mass scale, rather than $C\ensuremath{\lesssim}{(\mathrm{GM})}^{1/(n\ensuremath{-}2)}$ in terms of the hoop length C, which holds only when $n=3.$