Mon·Nov 7, 2022Monday·November 7, 2022

1. 01*

   Compositeness and several applications to exotic hadronic states with heavy quarks

   J.A. Oller🇪🇸 · Z.-H. Guo🇨🇳

   Several methods for studying the nature of a resonance are applied to resonances recently discovered in the bottonomium and charmonium sectors. We employ the effective-range expansion, the saturation of the width and compositeness of a resonance, as well as direct fits to data. The latter stem from generic $S$-matrix parameterization that account for relevant dynamical features associated to channels that couple strongly in an energy region around the resonance masses, in which their thresholds also lie. We report on results obtained with these methods for the resonances $Z_b(10610)$, $Z_b(10650)$, $Z_{cs}(3985)$, $Z_c(3900)$, $X(4020)$, $X(6900)$, $X(6825)$, and $P_{cs}(4459)$.

   hep-phnucl-thEPJ Web Conf.(2022)·0 citations
2. 02*

   Exploiting exotic LHC datasets for long-lived new particle searches

   Hesham El Faham🇧🇪 · Andrea Giammanco🇧🇪 · Jan Hajer🇵🇹

   Motivated by the expectation that new physics may manifest itself in the form of very heavy new particles, most of the operation time of the LHC is devoted to $pp$ collisions at the highest achievable energies and collision rates. The large collision rates imply tight trigger requirements that include high thresholds on the final-state particles' transverse momenta $p_T$ and an intrinsic background in the form of particle pileup produced by different collisions occurring during the same bunch crossing. This strategy is potentially sub-optimal for several well-motivated new physics models where new particles are not particularly heavy and can escape the online selection criteria of the multi-purpose LHC experiments due to their light mass and small coupling. A solution may be offered by complementary datasets that are routinely collected by the LHC experiments. These include heavy ion collisions, low-pileup runs for precision physics, and the so-called 'parking' and 'scouting' datasets. While some of them are motivated by other physics goals, they all have the usage of mild $p_T$ thresholds at the trigger-level in common. In this study, we assess the relative merits of these datasets for a representative model whose particular clean signature features long-lived resonances yielding displaced dimuon vertices. We compare the reach across those datasets for a simple analysis, simulating LHC data in Run 2 and Run 3 conditions with the Delphes simulation. We show that the scouting and parking datasets, which afford low-$p_T$ trigger thresholds by only using partial detector information and delaying the event reconstruction, respectively, have a reach comparable to the standard $pp$ dataset with conventional thresholds. We also show that heavy ion and low-pileup datasets are far less competitive for this signature.

   hep-phJHEP(2022)·3 citations
3. 03*

   Proton decay from quark and lepton compositeness

   Benoît Assi🇺🇸 · Bogdan A. Dobrescu🇺🇸

   Within a chiral $SU(15)$ gauge theory in which the Standard Model fermions are bound states of massless preons, we show that proton-decay operators are likely induced at the compositeness scale, ${\Lambda }_{\mathrm{pre}}$. Our estimate of the limit imposed by searches for proton decays is ${\Lambda }_{\mathrm{pre}}>10^4{\mathrm{TeV}}^{1/2}{C}_8^{1/4}{m}_{\mathcal{Q}}^{1/2}$, where $C_8$ is a rescaled coefficient of an 8-prebaryon operator induced by $SU(15)$ dynamics, and $m_{\mathcal{Q}}$ is the mass of a composite vectorlike quark. The latter has a lower limit related to the mass of a composite vectorlike lepton, which in turn is required by LHC searches to be above 1 TeV. For $C_8$ in the $10^{-5}-1$ range, the lower limit on ${\Lambda }_{\mathrm{pre}}$ varies between $3\times 10^3$ TeV and $5\times 10^4$ TeV. We point out that exotic proton decay modes, into a ${\pi }^{+}$ and a heavy right-handed neutrino, could be observed using the Super-Kamiokande or DUNE detectors.

   hep-phJHEP(2022)·9 citations
4. 04*

   Kaon processes in general 2HDM

   Girish Kumar🇹🇼

   We discuss new physics (NP) contributions to kaon mixing parameter ${\epsilon }_K$, direct CP violation parameter ${\epsilon }^{\prime }/\epsilon$ of $K\to \pi \pi$, and rare decays $K^{+}\to {\pi }^{+}\nu \bar{\nu }$, $K_L\to {\pi }^0\nu \bar{\nu }$ and $K_{L,S}\to {\mu }^{+}{\mu }^{-}$ in the context of general two Higgs doublet model. We focus on contributions of top quark related exotic couplings, and show that simultaneous presence of flavor conserving and flavor violating interactions can lead to large NP effects in kaon sector, while being consistent with the stringent constraints from B physics observables such as $B_{s(d)}$-${\bar{B}}_{s(d)}$ mixing, $B_s\to {\mu }^{+}{\mu }^{-}$, and $b\to s\gamma$. We stress on the importance of correlations between ${\epsilon }_K$, $K^{+}\to {\pi }^{+}\nu \bar{\nu }$ and $B_s\to {\mu }^{+}{\mu }^{-}$ that can be exploited to distinguish the parameter space corresponding to a light (sub-TeV) or heavy (TeV) scale charged Higgs boson.

   hep-phJ.Phys.Conf.Ser.(2023)·0 citations
5. 05*

   Study of weak-basis invariants in the universal seesaw model using Hilbert series

   Albertus Hariwangsa Panuluh🇯🇵 · Takuya Morozumi🇯🇵

   Universal Seesaw Model is a model which explains the mass hierarchy of the quark sector. This model introduces vector-like quarks. The top quark mass is generated in the electroweak scale and the other quark mass is generated using a seesaw-like mechanism. The invariant theory helps construct a weak-basis invariant. We study the weak-basis invariant (WBI) using Hilbert Series (HS) and apply it to the Universal Seesaw Model, particularly the one-generation case of the quark sector.

   hep-phJ.Phys.Conf.Ser.(2023)·1 citation
6. 06*

   Effective theory for universal seesaw model and FCNC

   Takuya Morozumi🇯🇵 · Apriadi Salim Adam🇮🇩 · Yuta Kawamura🇯🇵 · Albertus Hariwangsa Panuluh🇯🇵 · Yusuke Shimizu🇯🇵 · Kei Yamamoto🇯🇵

   We study the quark sector of the universal seesaw model with SU(2)${}_L$ $\times$ SU(2)${}_R$ $\times$ $U(1)$.The model incorporates the seesaw mechanism with the vector-like quarks (VLQs). The purpose of this work is to study the model with the effective theory. After integrating the heavy five VLQs, we derive the effective theory with four up-type quark and three down type quark. In this work, the FCNC of Z boson for top quark and top${}^{\prime }$ quark is derived.

   hep-phJ.Phys.Conf.Ser.(2023)·2 citations
7. 07*

   Vacuum stability and scalar masses in the superweak extension of the standard model

   Zoltán Péli🇭🇺

   We summarize our analysis for the vacuum stability of the superweak extension of the standard model. The parameter space allowed by the $W$-boson mass measurements and collider searches for a new scalar particle are also presented. The final result is a well defined non-vanishing portion of the parameter space, where the vacuum is stable, the couplings are perturbative and is not excluded by $W$ mass measurements and collider searches.

   hep-phPoS(2022)·1 citation
8. 08*

   Inclusive fluxes of secondary air-shower particles

   Hariom Sogarwal🇮🇳 · Prashant Shukla🇮🇳

   The particle showers produced in the atmosphere due to the interactions of primary cosmic particles require a thorough understanding in the backdrop of searches for rare interactions. In this work, we made a comprehensive study of air shower simulations using various combinations of hadronic models and particle transport code of the CORSIKA package. The primary proton and helium distributions are taken as power law which are scaled to match the measured flux in balloon experiments at the top of atmosphere. The shower simulation includes production, transport, and decays of secondaries up to the ground level. In this study, we focus on the bulk of the spectra and particles which is computationally intensive and hence parallel processing of events is done on computer cluster. We provide a way to normalize the simulation results to be compared with the ground-based measurements namely, single and multiple muon yields and their charge ratios as a function of zenith angle and momentum. This provides a basis for comparisons among the six model combinations used in this study and the differences are outlined. Most of the hadronic models in CORSIKA produce the bulk ground based measurements fairly well. We use one of the best model combinations to quantitatively predict the absolute and relative yields of various particles at ground level as well as their correlations with primaries and with each other. The leptonic ratios are obtained as a function of energy and zenith angle which are important inputs for the neutrino oscillation physics.

   hep-phastro-ph.HEhep-exJCAP(2024)·3 citations
9. 09*

   Hadronic decays of the heavy-quark-spin molecular partner of $T_{cc}^{+}$

   Zhao-Sai Jia🇨🇳 · Mao-Jun Yan🇨🇳 · Zhen-Hua Zhang🇨🇳 · Pan-Pan Shi🇨🇳 · Gang Li🇨🇳 · Feng-Kun Guo🇨🇳

   Starting from the hypothesis that the $T_{cc}^{+}$ discovered at LHCb is a $D^{\ast +}{D}^0/D^{\ast 0}{D}^{+}$ hadronic molecule, we consider the partial width of its heavy quark spin partner, the $T_{cc}^{\ast +}$ as a $D^{\ast +}{D}^{\ast 0}$ shallow bound state, decaying into the $D^{\ast }D\pi$ final states including the contributions of the $D^{\ast }D$ and $D^{\ast }\pi$ final state interaction by using a nonrelativistic effective field theory. Because of the existence of the $T_{cc}^{+}$ pole, the $I=0$ $D^{\ast }D$ rescattering can give a sizeable correction up to about $40\%$ to the decay widths considering only the tree diagrams, and the $D^{\ast }\pi$ rescattering correction is about $10\%$. The four-body partial widths of the $T_{cc}^{\ast +}$ into $DD\pi \pi$ are also explicitly calculated, and we find that the interference effect between different intermediate $D^{\ast }D\pi$ states is small. The total width of the $T_{cc}^{\ast +}$ is predicted to be about 41 keV.

   hep-phPRD(2023)·18 citations
10. 10*

    Decorrelation with conditional normalizing flows

    Samuel Klein🇨🇭 · Tobias Golling🇨🇭

    The sensitivity of many physics analyses can be enhanced by constructing discriminants that preferentially select signal events. Such discriminants become much more useful if they are uncorrelated with a set of protected attributes. In this paper we show that a normalizing flow conditioned on the protected attributes can be used to find a decorrelated representation for any discriminant. As a normalizing flow is invertible the separation power of the resulting discriminant will be unchanged at any fixed value of the protected attributes. We demonstrate the efficacy of our approach by building supervised jet taggers that produce almost no sculpting in the mass distribution of the background.

    hep-phcs.LG14 citations
11. 11*

    New Clues About Light Sterile Neutrinos: Preference for Models with Damping Effects in Global Fits

    J.M. Hardin🇺🇸 · I. Martinez-Soler🇺🇸 · A. Diaz🇺🇸 · M. Jin🇺🇸 · N.W. Kamp🇺🇸 · C.A. Argüelles🇺🇸 · J.M. Conrad🇺🇸 · M.H. Shaevitz🇺🇸

    This article reports global fits of short-baseline neutrino data to oscillation models involving light sterile neutrinos. In the commonly-used 3+1 plane wave model, there is a well-known 4.9$\sigma$ tension between data sets sensitive to appearance versus disappearance of neutrinos. We find that models that damp the oscillation prediction for the reactor data sets, especially at low energy, substantially improve the fits and reduce the tension. We consider two such scenarios. The first scenario introduces the quantum mechanical wavepacket effect that accounts for the source size in reactor experiments into the 3+1 model. We find that inclusion of the wavepacket effect greatly improves the overall fit compared to a 3$\nu$ model by $\Delta {\chi }^2/$DOF$=61.1/4$ ($7.1\sigma$ improvement) with best-fit $\Delta m^2=1.4$ eV${}^2$ and wavepacket length of 67fm. The internal tension is reduced to 3.4$\sigma$. If reactor-data only is fit, then the wavepacket preferred length is 91 fm ($>20$ fm at 99\% CL). The second model introduces oscillations involving sterile flavor and allows the decay of the heaviest, mostly sterile mass state, ${\nu }_4$. This model introduces a damping term similar to the wavepacket effect, but across all experiments. Compared to a three-neutrino fit, this has a $\Delta {\chi }^2/$DOF$=60.6/4$ ($7\sigma$ improvement) with preferred $\Delta m^2=1.4$ eV${}^2$ and decay $\Gamma =0.35$ eV${}^2$. The internal tension is reduced to 3.7$\sigma$. For many years, the reactor event rates have been observed to have structure that deviates from prediction. Community discussion has focused on an excess compared to prediction observed at 5 MeV; however, other deviations are apparent. This structure has $L$ dependence that is well-fit by the damped models. Before assuming this points to new physics, we urge closer examination of systematic effects that could lead to this $L$ dependence.

    hep-phhep-exJHEP(2023)·37 citations
12. 12*

    Higgs Production and $H^0\to c\overline{c}$ at a Future Muon-Ion Collider

    Pavan Ahluwalia🇺🇸 · Justine Choi🇰🇷 · Simba Masters🇺🇸 · Austin Mullins🇺🇸 · Noah Randall🇺🇸 · Stephen J. Sekula🇺🇸

    We investigate the production of Higgs bosons in neutral- and charged-current interactions at a future Muon-Ion Collider (MuIC) with emphasis on $H^0\to c\overline{c}$ decay. In particular, we focus on the leading production mechanisms and explore the impact of a range of Parton Distribution Function (PDF) scenarios, with emphasis on the role of heavy intrinsic quark flavor. We emphasize estimates of non-resonant di-charm background production and explore the impact of this background on a possible future measurement of $H^0\to c\overline{c}$ at a future Muon-Ion Collider facility.

    hep-ph3 citations
13. 13*

    White dwarfs as a probe of exceptionally light QCD axions

    Reuven Balkin🇮🇱 · Javi Serra🇩🇪 · Konstantin Springmann🇩🇪 · Stefan Stelzl🇩🇪 · Andreas Weiler🇩🇪

    We study the effects of exceptionally light QCD axions on the stellar configuration of white dwarfs. At finite baryon density, the non-derivative coupling of the axion to nucleons displaces the axion from its in-vacuum minimum which implies a reduction of the nucleon mass. This dramatically alters the composition of stellar remnants. In particular, the modifications of the mass-radius relationship of white dwarfs allow us to probe large regions of unexplored parameter space without requiring that axions are dark matter.

    hep-phastro-ph.HEastro-ph.SRPRD(2024)·95 citations
14. 14*

    Measuring Oscillations with A Million Atmospheric Neutrinos

    C. A. Argüelles🇺🇸 · P. Fernández🇬🇧 · I. Martínez-Soler🇺🇸 · M. Jin🇺🇸

    After two decades of measurements, neutrino physics is now advancing into the precision era. Withthe long-baseline experiments designed to tackle current open questions, a new query arises: can atmospheric neutrino experiments also play a role? To that end, we analyze the expected sensitivity of current and near-future water(ice)-Cherenkov atmospheric neutrino experiments in the context of standard three-flavor neutrino oscillations. In this first in depth combined atmospheric neutrino analysis, we analyze the current shared systematic uncertainties arising from the common flux and neutrino-water interactions. We then implement the systematic uncertainties of each experiment in detail and develop the atmospheric neutrino simulations for Super-Kamiokande, with and without neutron-tagging capabilities, IceCube Upgrade, ORCA, and Hyper-Kamiokande detectors. We carefully review the synergies and features of these experiments to examine the potential of a joint analysis of these atmospheric neutrino data in resolving the ${\theta }_{23}$ octant at 99% confidence level, and determining the neutrino mass ordering above 5$\sigma$ by 2030. Additionally, we assess the capability to constrain ${\theta }_{13}$ and the CP -violating phase (${\delta }_{CP}$) in the leptonic sector independently from reactor and accelerator neutrino data. A combination of the atmospheric neutrino measurements will enhance the sensitivity to a greater extent than the simple sum of individual experiment results reaching more than 3$\sigma$ for some values of ${\delta }_{CP}$ . These results will provide vital information for next-generation accelerator neutrino oscillation experiments such as DUNE and Hyper-Kamiokande.

    hep-phhep-exPRX(2023)·25 citations
15. 15*

    Methods on compositeness and related aspects

    J.A. Oller🇪🇸

    In many physical applications, bound states and/or resonances are observed, which raises the question whether these states are elementary or composite. Here we elaborate on several methods for calculating the compositeness $X$ of bound states and resonances in Quantum Mechanics, and in Quantum Field Theory by introducing particle number operators. For resonances $X$ is typically complex and we discuss how to get meaningful results by using certain phase transformations in the $S$ matrix.

    ↳ quant-phhep-phnucl-thEPJ Web Conf.(2022)·2 citations
16. 16*

    Unitarizing infinite-range forces: Graviton-graviton scattering, the graviball, and Coulomb scattering

    J.A. Oller🇪🇸

    We study graviton-graviton scattering in partial-wave amplitudes after unitarizing their Born terms. In order to apply $S$-matrix techniques, based on unitarity and analyticity, we introduce an $S$-matrix associated to this resummation that is free of infrared divergences. This is achieved by removing the diverging phase factor calculated by Weinberg that multiplies the $S$ matrix, and that stems from the virtual infrared gravitons. A scalar graviton-graviton resonance with vacuum quantum numbers is obtained as a pole in the nonperturbative $S$-wave amplitude, which is called the graviball. Its resonant effects along the physical real $s$-axis may peak at values substantially lower than the UV cutoff squared of the theory, similarly to the $\sigma$ resonance in QCD. These techniques are also applied to study nonrelativistic Coulomb scattering up to next-to-leading order in the unitarization program. A comparison with the exact known solution is very illuminating.

    ↳ hep-thhep-phEPJ Web Conf.(2022)·4 citations
17. 17*

    Long Range Plan: Dense matter theory for heavy-ion collisions and neutron stars

    Alessandro Lovato🇺🇸 · Travis Dore🇩🇪 · Robert D. Pisarski🇺🇸 · Bjoern Schenke🇺🇸 · Katerina Chatziioannou🇺🇸 · Jocelyn S. Read🇺🇸 · Philippe Landry🇨🇦 · Pawel Danielewicz🇺🇸 · Dean Lee🇺🇸 · Scott Pratt🇺🇸 · Fabian Rennecke🇩🇪 · Hannah Elfner🇩🇪 and 52 other authors

    Since the release of the 2015 Long Range Plan in Nuclear Physics, major events have occurred that reshaped our understanding of quantum chromodynamics (QCD) and nuclear matter at large densities, in and out of equilibrium. The US nuclear community has an opportunity to capitalize on advances in astrophysical observations and nuclear experiments and engage in an interdisciplinary effort in the theory of dense baryonic matter that connects low- and high-energy nuclear physics, astrophysics, gravitational waves physics, and data science

    ↳ nucl-thastro-ph.HEhep-ph114 citations
18. 18*

    Relativistic resistive magneto-hydrodynamics code for high-energy heavy-ion collisions

    Kouki Nakamura🇯🇵 · Takahiro Miyoshi🇯🇵 · Chiho Nonaka🇯🇵 · Hiroyuki R. Takahashi🇯🇵

    We construct a relativistic resistive magneto-hydrodynamic (RRMHD) numerical simulation code for high-energy heavy-ion collisions. We split the system of differential equations into two parts, a non-stiff and a stiff part. For the non-stiff part, we evaluate the numerical flux using HLL approximated Riemann solver and execute the time integration by the second-order of Runge-Kutta algorithm. For the stiff part, which appears in Ampere's law, we integrate the equations using semi-analytic solutions of the electric field. We employ the generalized Lagrange multiplier method to ensure the divergence-free constraint for the magnetic field and Gauss's law. We confirm that our code reproduces well the results of standard RRMHD tests in the Cartesian coordinates. In the Milne coordinates, the code with high conductivity is validated against relativistic ideal MHD tests. We also verify the semi-analytic solutions of the accelerating longitudinal expansion of relativistic resistive magneto-hydrodynamics in high-energy heavy-ion collisions in a comparison with our numerical result. Our numerical code reproduces these solutions.

    ↳ nucl-thhep-phnucl-exEPJC(2023)·22 citations
19. 19*

    Unpolarized Transverse-Momentum-Dependent Parton Distributions of the Nucleon from Lattice QCD

    Lattice Parton Collaboration: Jin-Chen He🇨🇳 · Min-Huan Chu🇨🇳 · Jun Hua🇨🇳 · Xiangdong Ji🇺🇸 · Andreas Schäfer🇩🇪 · Yushan Su🇺🇸 · Wei Wang🇨🇳 · Yibo Yang🇨🇳 · Jian-Hui Zhang🇨🇳 · Qi-An Zhang

    We present a first lattice QCD calculation of the unpolarized nucleon's isovector transverse-momentum-dependent parton distribution functions (TMDPDFs), which are essential to predict observables of multi-scale, semi-inclusive processes in the standard model. We use a $N_f=2+1+1$ MILC ensemble with valence clover fermions on a highly improved staggered quark (HISQ) sea to compute the quark momentum distributions in a large-momentum nucleon on the lattice. The state-of-the-art techniques in renormalization and extrapolation in the correlation distance on the lattice are adopted. {The perturbative kernel up to next-to-next-to-leading order is taken into account}, and the dependence on the pion mass and the hadron momentum is explored. Our results are qualitatively comparable with phenomenological TMDPDFs, which provide an opportunity to predict high energy scatterings from first principles.

    ↳ hep-lathep-phPRD(2024)·60 citations
20. 20*

    Quasinormal Modes and Love Numbers of Kerr Black Holes from AdS${}_2$ Black Holes

    Alex Kehagias🇬🇷 · Davide Perrone🇨🇭 · Antonio Riotto🇨🇭

    We show that the linear perturbations of any spin field in the near-zone limit of the Kerr black hole are identical to those of an AdS${}_2$ black hole which enjoys the same basic properties of the Kerr black hole. Thanks to this identification, we calculate the spectrum of the quasinormal modes and the Love numbers of Kerr black holes using an AdS${}_2$/CFT${}_1$ correspondence and a group theoretical approach.

    ↳ hep-thgr-qchep-phJCAP(2023)·24 citations
21. 21*

    Precision Measurement of Trident Production in Strong Electromagnetic Fields

    Christian F. Nielsen🇩🇰 · Robert Holtzapple🇺🇸 · Mads M. Lund🇩🇰 · Jeppe H. Surrow🇩🇰 · Allan H. Sørensen🇩🇰 · Ulrik I. Uggerhøj🇩🇰

    We demonstrate experimentally that the trident process $e^{-}\to e^{-}{e}^{+}{e}^{-}$ in a strong external field, with a spatial extension comparable to the effective radiation length, is well understood theoretically. The experiment, conducted at CERN, probes values for the strong field parameter $\chi$ up to 2.4. Experimental data and theoretical expectations using the Local Constant Field Approximation show remarkable agreement over almost 3 orders of magnitude in yield.

    ↳ hep-exhep-phPRL(2023)·20 citations
22. 22*

    Generalized Hilltop Inflation

    Helena Grete Lillepalu🇪🇪 · Antonio Racioppi🇪🇪

    We study a generalized version of hilltop inflation where the standard hilltop potential has been raised to a power and we allow fractional numbers for both the original hilltop power ($m$) and the overall exponent ($n$). In the parameter space studied, agreement with the latest experimental constraints favors high values for $m$ and low values for $n$. Finally, we also find that in all the configurations studied, the inflationary scale always sits around the grand unification scale.

    ↳ astro-ph.COgr-qchep-phEur.Phys.J.Plus(2023)·24 citations
23. 23*

    Proton Synchrotron, an explanation for possible extended VHE gamma-ray activity of TXS 0506+056 in 2017

    Sunanda🇮🇳 · Reetanjali Moharana🇮🇳 · Pratik Majumdar🇮🇳

    TXS 0506+056, a source of the extreme energy neutrino event, IceCube-170922A, was observed on 22 September 2017. The Fermi-LAT detector reported high energy (HE) $\gamma$-ray flare between 100 MeV and 100 GeV starting from 15 September 2017 from this source. Several attempts to trace the very high energy (VHE) gamma-ray counterparts around the IceCube-170922A resulted in no success. Only after 28 September, the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes observed the first VHE gamma-rays from the blazar above 100 GeV. The $\sim$ 41 hr survey resulted in VHE-$\gamma$ ray activity till 31 October 2017. Here we propose the extended GeV $\gamma -$rays can be explained by taking two production channels, electron synchrotron self Compton and proton synchrotron for HE and VHE emissions, respectively. The 45 days of VHE emission from the peak of the HE-flare can be explained with $L_p^{\prime }\simeq 10^{47}$ erg/sec in the jet frame and magnetic field of 2.4 G, consistent with the $L_{Edd}$ for a blackhole mass $5\times 10^9{M}_{\odot }$

    ↳ astro-ph.HEhep-phPRD(2022)·5 citations
24. 24*

    Questions on calculation of primordial power spectrum with large spikes: the resonance model case

    Keisuke Inomata🇺🇸 · Matteo Braglia🇺🇸 · Xingang Chen🇺🇸 · Sébastien Renaux-Petel🇫🇷

    Inflationary models predicting a scale-dependent large amplification of the density perturbations have recently attracted a lot of attention because the amplified perturbations can seed a sizable amount of primordial black holes (PBHs) and stochastic background of gravitational waves (GWs). While the power spectra in these models are computed based on the linear equation of motion, it is not obvious whether loop corrections are negligible when such a large amplification occurs during inflation. In this paper, as a first step to discuss the loop corrections in such models, we use the in-in formalism and calculate the one-loop scalar power spectrum numerically and analytically in an illustrative model where the density perturbations are resonantly amplified due to oscillatory features in the inflaton potential. Our calculation is technically new in that the amplified perturbations are numerically taken into account in the in-in formalism for the first time. In arriving at our analytical estimates, we highlight the role that the Wronskian condition of perturbations, automatically satisfied in our model, plays in obtaining the correct estimates. We also discuss the necessary conditions for subdominant loop corrections in this model. We find that, for the typical parameter space leading to the $\mathcal{O}(10^7)$ amplification of the power spectrum required for a sufficient PBH production, the one-loop power spectrum dominates over the tree-level one, indicating the breakdown of the perturbation theory.

    ↳ astro-ph.COgr-qchep-phJCAP(2023)·104 citations
25. 25*

    Cosmic topology. Part I. Limits on orientable Euclidean manifolds from circle searches

    Pip Petersen · Yashar Akrami · Craig J. Copi · Andrew H. Jaffe · Arthur Kosowsky · Deyan P. Mihaylov · Glenn D. Starkman · Andrius Tamosiunas · Johannes R. Eskilt · Özenç Güngör · Samanta Saha · Quinn Taylor (COMPACT Collaboration)

    The Einstein field equations of general relativity constrain the local curvature at every point in spacetime, but say nothing about the global topology of the Universe. Cosmic microwave background anisotropies have proven to be the most powerful probe of non-trivial topology since, within $\Lambda$CDM, these anisotropies have well-characterized statistical properties, the signal is principally from a thin spherical shell centered on the observer (the last scattering surface), and space-based observations nearly cover the full sky. The most generic signature of cosmic topology in the microwave background is pairs of circles with matching temperature and polarization patterns. No such circle pairs have been seen above noise in the WMAP or Planck temperature data, implying that the shortest non-contractible loop around the Universe through our location is longer than 98.5% of the comoving diameter of the last scattering surface. We translate this generic constraint into limits on the parameters that characterize manifolds with each of the nine possible non-trivial orientable Euclidean topologies, and provide a code which computes these constraints. In all but the simplest cases, the shortest non-contractible loop in the space can avoid us, and be shorter than the diameter of the last scattering surface by a factor ranging from 2 to at least 6. This result implies that a broader range of manifolds is observationally allowed than widely appreciated. Probing these manifolds will require more subtle statistical signatures than matched circles, such as off-diagonal correlations of harmonic coefficients.

    ↳ astro-ph.COgr-qchep-phhep-thJCAP(2023)·23 citations
26. 26*

    Did JWST observe imprints of axion miniclusters or primordial black holes?

    Gert Hütsi🇪🇪 · Martti Raidal🇪🇪 · Juan Urrutia🇪🇪 · Ville Vaskonen🇪🇪 · Hardi Veermäe🇪🇪

    The James Webb Space Telescope has detected surprisingly luminous early galaxies that indicate a tension with the $\Lambda$CDM. Motivated by scenarios including axion miniclusters or primordial black holes, we consider power-law modifications of the matter power spectrum. We show that the tension could be resolved if dark matter consists of $2\times 10^{-18}\mathrm{eV}$ axions or if a fraction $f_{\mathrm{PBH}}>0.005$ of dark matter is composed of compact heavy $4\times 10^6{M}_{\odot }(f_{\mathrm{PBH}}/0.005{)}^{-1}$ structures such as primordial black hole clusters. However, in both cases, the star formation efficiency needs to be significantly enhanced.

    ↳ astro-ph.COhep-phPRD(2023)·83 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.