HEP Phenomenology·hep-ph

Fri·Aug 25, 2023Friday·August 25, 2023

26 papers—17 primary·9 cross-listed·reconstructed*

01*
Improving Generative Model-based Unfolding with Schrödinger Bridges
Sascha Diefenbacher🇺🇸 · Guan-Horng Liu🇺🇸 · Vinicius Mikuni🇺🇸 · Benjamin Nachman🇺🇸 · Weili Nie🇺🇸
Machine learning-based unfolding has enabled unbinned and high-dimensional differential cross section measurements. Two main approaches have emerged in this research area: one based on discriminative models and one based on generative models. The main advantage of discriminative models is that they learn a small correction to a starting simulation while generative models scale better to regions of phase space with little data. We propose to use Schroedinger Bridges and diffusion models to create SBUnfold, an unfolding approach that combines the strengths of both discriminative and generative models. The key feature of SBUnfold is that its generative model maps one set of events into another without having to go through a known probability density as is the case for normalizing flows and standard diffusion models. We show that SBUnfold achieves excellent performance compared to state of the art methods on a synthetic Z+jets dataset.
hep-phcs.LGhep-exPRD(2024)·50 citations
02*
Gluon TMD fragmentation function into quarkonium
Miguel G. Echevarria🇪🇸 · Samuel F. Romera🇪🇸 · Ignazio Scimemi🇪🇸
We compute the gluon transverse-momentum-dependent fragmentation function (TMDFF) at next-to-leading order (NLO) into heavy quarkonium in the color-octet $^{3} S_{1}^{[8]}$ channel, based on the NRQCD factorization approach. The spurious rapidity divergences are explicitly shown to cancel in a well-defined TMDFF, which incorporates the needed soft factor. We also compute the integrated gluon FF at NLO in the same $^{3} S_{1}^{[8]}$ channel, and show that the matching coefficient of the TMDFF onto the FF at large transverse momentum is the expected one. These results are relevant to perform precise and sensible phenomenological studies of transverse-momentum spectra of quarkonium production, for which the production mechanism through fragmentation plays a relevant role, like in the future Electron-Ion Collider.
hep-phJHEP(2023)·16 citations
03*
Tensor meson couplings in AdS/QCD
Shahin Mamedov🇦🇿 · Zeynab Hashimli🇦🇿 · Shahriyar Jafarzade🇵🇱
We study the hadronic and radiative couplings of the $f_{2} (1270)$ meson within the hard- and soft-wall models of AdS/QCD. The results for the tensor meson-nucleon-nucleon coupling ( $g_{f_{2} N N}$ ) and tensor meson-photon-vector meson coupling ( $g_{f_{2} γ ρ}$ ) are compared to the ones obtained by using the dispersion relations and amplitude methods, respectively. Qualitative agreement with different analyses implies the reliability of the holographic description of spin-2 meson.
hep-phPRD(2023)·8 citations
04*
Virtual states in the coupled-channel problems with an improved complex scaling method
Yan-Ke Chen🇨🇳 · Lu Meng🇩🇪 · Zi-Yang Lin🇨🇳 · Shi-Lin Zhu🇨🇳
We improve the complex scaling method (CSM) to obtain virtual states, which were previously challenging in the conventional CSM. Our approach solves the Schrödinger equation in the momentum space as an eigenvalue problem by choosing the flexible contours. It proves to be highly effective in identifying the poles across the different Riemann sheets in the multichannel scatterings. It is more straightforward and efficient than searching for the zeros of the Fredholm determinant of the Lippmann-Schwinger equation using the root-finding algorithms. This advancement significantly extends the capabilities of the CSM in accurately characterizing the resonances and virtual states in quantum systems.
hep-phhep-latnucl-thphysics.atom-ph+1PRD(2024)·21 citations
05*
High scale validity of two Higgs doublet scenarios with a real scalar singlet dark matter
Subhaditya Bhattacharya🇮🇳 · Atri Dey🇮🇪 · Jayita Lahiri🇩🇪 · Biswarup Mukhopadhyaya🇮🇳
We study the high-scale validity of two kinds of two Higgs doublet models (2HDM), namely, Type-II and Type-X, but with a scalar SU(2) singlet dark matter (DM) candidate in addition in each case. The additional quartic couplings involving the DM particle in the scalar potential in both the scenarios bring in additional constraints from the requirement of perturbative unitarity and vacuum stability. DM relic density and direct search constraints play a crucial role in this analysis as the perturbative unitarity of the DM-Higgs portal couplings primarily decide the high scale validity of the model. We find that, within the parameter regions thus restricted, the Type-II scenario must have a cut-off at around $1 0^{6}$ GeV, while the Type-X scenario admits of validity upto the Planck scale. However, only those regions which are valid upto about $1 0^{8}$ GeV in Type-X 2HDM is amenable to detection at the High-luminosity LHC (upto 3000 $f b^{- 1}$ ), while most of the parameter space of the Type-II scenario mentioned above is likely to be detectable.
hep-phPRD(2024)·5 citations
06*
Inverse magnetic catalysis effect and current quark mass effect on mass spectra and Mott transitions of pions under external magnetic field
Luyang Li🇨🇳 · Shijun Mao🇨🇳
Mass spectra and Mott transition of pions $(π^{0}, π^{\pm})$ at finite temperature and magnetic field are investigated in a two-flavor NJL model, and we focus on the inverse magnetic catalysis (IMC) effect and current quark mass (CQM) effect. Due to the dimension reduction of the constituent quarks, the pion masses jump at their Mott transitions, which is independent of the IMC effect and CQM effect. We consider the IMC effect by using a magnetic dependent coupling constant, which is a monotonic decreasing function of magnetic field. With IMC effect, the Mott transition temperature of $π^{0}$ meson $T_{m}^{0}$ is a monotonic decreasing function of magnetic field. For charged pions $π^{\pm}$ , the Mott transition temperature $T_{m}^{+}$ fast increases in weak magnetic field region and then decreases with magnetic field, which are accompanied with some oscillations. Comparing with the case without IMC effect, $T_{m}^{0}$ and $T_{m}^{+}$ are lower when including IMC effect. CQM effect are considered by varying parameter $m_{0}$ in non-chiral limit. For $π^{0}$ meson, $T_{m}^{0}$ is not a monotonic function of magnetic field with low $m_{0}$ , but it is a monotonic decreasing function with larger $m_{0}$ . In the weak magnetic field region, $T_{m}^{0}$ is higher for larger $m_{0}$ , but in the strong magnetic field region, it is lower for larger $m_{0}$ . For $π^{+}$ meson, $T_{m}^{+}$ is only quantitatively modifies by current quark mass effect, and it becomes higher with larger $m_{0}$ .
hep-phnucl-thPRD(2023)·10 citations
07*
Study of four-body decays $B_{(s)} \to (π π) (π π)$ in the perturbative QCD approach
Da-Cheng Yan (Changzhou U.)🇨🇳 · Zhou Rui (NCUST, Taiyuan)🇨🇳 · Yan Yan (Changzhou U.)🇨🇳 · Ya Li (Nanjing Agricultural U.)🇨🇳
In this work, we make a systematical study on the four-body $B_{(s)} \to (π π) (π π)$ decays in the perturbative QCD approach, where the $π π$ invariant mass spectra are dominated by the vector resonance $ρ (770)$ and the scalar resonance $f_{0} (980)$ . We improve the Gengenbauer moments for the longitudinal $P$ -wave two-pion distribution amplitudes (DAs) by fitting the PQCD factorization formulas to measured branching ratios of three-body and four-body $B$ decays. With the fitted Gegenbauer moments, we make predictions for the branching ratios and direct $C P$ asymmetries of four-body $B_{(s)} \to (π π) (π π)$ decays. We extract the branching ratios of two-body $B_{(s)} \to ρρ$ from the corresponding four-body decay modes and calculate the relevant polarization fractions. We find that the $B (B^{0} \to ρ^{+} ρ^{-})$ is consistent with the previous theoretical predictions and data. The leading-order PQCD calculations of the $B (B^{+} \to ρ^{+} ρ^{0})$ , $B (B^{0} \to ρ^{0} ρ^{0})$ and the $f_{0} (B^{0} \to ρ^{0} ρ^{0})$ are a bit lower than the experimental measurements, which should be further examined. In addition, the "true" and "fake" triple-product asymmetries (TPAs) in the $B_{(s)} \to (π π) (π π)$ decays are also analyzed. The sizable averaged TPA $A_{T-true}^{1, ave} = 25.26%$ of the color-suppressed decay $B^{0} \to ρ^{0} ρ^{0} \to (π^{+} π^{-}) (π^{+} π^{-})$ is predicted for the first time, which deviates a lot from the so-called "true" TPA $A_{T-true}^{1} = 7.92%$ due to the large direct $C P$ violation. A large "fake" TPA $A_{T-fake}^{1} = 24.96%$ of the decay $B^{0} \to ρ^{0} ρ^{0} \to (π^{+} π^{-}) (π^{+} π^{-})$ is also found, which indicates the significance of the final-state interactions. The predictions in this work can be tested by LHCb and Belle-II experiments in the near future.
hep-phEPJC(2023)·7 citations
08*
Relic abundance of dark matter with coannihilation in non-standard cosmological scenarios
Fangyu Liu🇨🇳 · Hoernisa Iminniyaz🇨🇳
We investigate the relic abundance of dark matter from coannihilation in non-standard cosmological scenarios. We explore the effect of coannihilation on the relic density of dark matter and freeze out temperature in quintessence model with kination phase and brane world cosmological scenarios. Since the Hubble expansion rate is enhanced in quintessence and brane world cosmological models, it causes the larger relic density compared to that in the standard one. On the other hand, the relic density of dark matter is decreased due to the coannihilation in the standard cosmological scenario. After including coannihilation in quintessence or brane world cosmological scenarios, we find the decrease of the relic density of dark matter is slightly slower than that in the standard cosmological scenario.
hep-phPhys.Dark Univ.(2024)·0 citations
09*
Sterile Neutrino Portal Dark Matter from Semi-Production
Ang Liu🇨🇳 · Feng-Lan Shao🇨🇳 · Zhi-Long Han🇨🇳 · Yi Jin🇨🇳 · Honglei Li🇨🇳
In this paper, we study the feeble sterile neutrino portal dark matter under the $Z_{3}$ symmetry. The dark sector consists of one fermion singlet $χ$ and one scalar singlet $χ$ , which transforms as $χ \to e^{i 2 π /3} χ, ϕ \to e^{i 2 π /3} ϕ$ under the $Z_{3}$ symmetry. Regarding fermion singlet $χ$ as the dark matter candidate, the new interaction terms $y_{χ} ϕ χ^{c} ˉ χ$ and $μ ϕ^{3} /2$ could induce various new production channels. For instance, when $m_{ϕ} > 2 m_{χ}$ , the pair decay $ϕ \to χχ$ could be the dominant channel, rather than the delayed decay $ϕ \to χ ν$ . Another appealing scenario is when the dark sector is initially produced through the scattering process as $N N \to χχ, N N \to ϕϕ, h ν \to χ ϕ$ , then the semi-production processes $N χ \to ϕϕ, N ϕ \to ϕ χ, N χ \to χχ$ could lead to the exponential growth of dark sector abundances. The phenomenology of sterile neutrino and the cosmological impact of the dark scalar are also considered in the $Z_{3}$ symmetric model.
hep-phPRD(2024)·6 citations
10*
Dark Mater Interactions From An Extra U(1) gauge symmetry with kinetic mixing and Higgs charge
Lianyou Shan🇨🇳 · Zhao-Huan Yu🇨🇳
We investigate fermionic dark matter interactions with standard model particles from an additional $U (1)_{X}$ gauge symmetry, assuming kinetic mixing between the $U (1)_{X}$ and $U (1)_{Y}$ gauge fields as well as a nonzero $U (1)_{X}$ charge of the Higgs doublet. For ensuring gauge-invariant Yukawa interactions and the cancellation of gauge anomalies, the standard model fermions are assigned $Y$ -sequential $U (1)_{X}$ charges proportional to the Higgs charge. Although the Higgs charge should be small due to collider constraints, it is useful to decrease the effective cross section of dark matter scattering off nucleons by two orders of magnitude and easier evade from direct detection bounds. After some numerical scans performed in the parameter space, we find that the introduction of the Higgs charge can also enhance the dark matter relic density by at least two orders of magnitude. When the observed relic density and the direct detection constraints are tangled, at the case where the resonance effect is important for dark matter freeze-out, the Higgs charge can expand physical windows to some extent by relieving the tension between the relic density and the direct detection.
hep-phCPC(2024)·1 citation
11*
Gravitational Waves from Phase Transitions in Scale Invariant Models
Amine Ahriche🇦🇪 · Shinya Kanemura🇯🇵 · Masanori Tanaka
We investigate the properties of the gravitational waves (GWs) generated during a strongly first order electroweak phase transition (EWPT) in models with the classical scale invariance (CSI). Here, we distinguish two parameter space regions that correspond to the cases of (1) light dilaton and (2) purely radiative Higgs mass (PRHM). In the CSI models, the dilaton mass, or the Higgs mass in the PRHM case, in addition to some triple scalar couplings are fully triggered by the radiative corrections (RCs). In order to probe the RC effects on the EWPT strength and on the GW spectrum, we extend the standard model by a real singlet to assist the electroweak symmetry breaking and an additional scalar field $Q$ with multiplicity $N_{Q}$ and mass $m_{Q}$ . After imposing all theoretical and experimental constraints, we show that a strongly first order EWPT with detectable GW spectra can be realized for the two cases of light dilaton and PRHM. We also show the corresponding values of the relative enhancement of the cross section for the di-Higgs production process, which is related to the triple Higgs boson coupling. We obtain the region in which the GW spectrum can be observed by different future experiments such as LISA and DECIGO. We also show that the scenarios (1) and (2) can be discriminated by future GW observations and measurements of the di-Higgs productions at future colliders.
hep-phastro-ph.COJHEP(2024)·14 citations
12*
Analysis of the strong decays of SU(3) partners of the $Ω (2012)$ baryon
T.M.Aliev🇹🇷 · S.Bilmis🇹🇷 · M.Savci🇹🇷
We estimate the coupling constants and decay widths of the $S U (3)$ partners of the $Ω (2012)$ hyperon, as discovered by the BELLE Collaboration, using the light cone sum rules method. Our study includes a comparison of the obtained results for relevant decay widths with those derived within the framework of the flavor $S U (3)$ analysis. We observe a good agreement between the predictions of both approaches. The results we obtain for the branching ratio can provide helpful insights for determining the nature of the $S U (3)$ partners of the $Ω (2012)$ baryon.
hep-phhep-exhep-latCPC(2024)·1 citation
13*
Chiral perturbative reconstruction of the complex orthogonal matrix $R$ in Casas--Ibarra parameterization
Masaki J. S. Yang🇯🇵
In this letter, we perform a chiral perturbative analysis by singular values $m_{D i}$ of the Dirac mass matrix $m_{D}$ for the type-I seesaw mechanism. In the basis where $m_{D} = V m_{D}^{diag} U^{†}$ is diagonal, the mass matrix of right-handed neutrinos $M_{R}$ is written by $M_{R} = m_{D}^{diag} m^{- 1} m_{D}^{diag}$ . If the mass matrix of light neutrinos $m$ has an inverse matrix and the singular values $m_{D i}$ are hierarchical ( $m_{D 1} ≪ m_{D 2} ≪ m_{D 3}$ ), the singular values $M_{i}$ and diagonalization matrix $U$ of $M_{R}$ are obtained perturbatively. By treating $m_{D i}$ and $V$ as input parameters, $m_{D}$ is represented in the basis where $M_{R}$ is diagonal, and we perturbatively derive the orthogonal matrix $R$ in Casas--Ibarra parameterization. As a result, $R$ is independent of $m_{D i}$ in the leading order, and it is reconstructed as an orthonormal basis $R_{i 1} ≃ \pm m_{i} / m_{11} (U_{MNS}^{T} V^{*})_{i 1}, R_{i 2} ≃ \pm ϵ_{ij k} R_{j 3} R_{k 1}, R_{i 3} ≃ \pm (U_{MNS}^{†} V)_{i 3} / m_{i} (m^{- 1})_{33}$ . Here, $m_{i}$ is the masses of light neutrinos and $\pm$ denotes the independent degree of freedom for each column vector.
hep-ph1 citation
14*
Searching for Heavy Leptophilic $Z^{'}$ : from Lepton Colliders to Gravitational Waves
Arnab Dasgupta🇺🇸 · P. S. Bhupal Dev🇺🇸 · Tao Han🇺🇸 · Rojalin Padhan🇮🇳 · Si Wang🇺🇸 · Keping Xie🇺🇸
We study the phenomenology of leptophilic $Z^{'}$ gauge bosons at the future high-energy $e^{+} e^{-}$ and $μ^{+} μ^{-}$ colliders, as well as at the gravitational wave observatories. The leptophilic $Z^{'}$ model, although well-motivated, remains largely unconstrained from current low-energy and collider searches for $Z^{'}$ masses above $O (100 GeV)$ , thus providing a unique opportunity for future lepton colliders. Taking $U (1)_{L_{α} - L_{β}} (α, β = e, μ, τ)$ models as concrete examples, we show that future $e^{+} e^{-}$ and $μ^{+} μ^{-}$ colliders with multi-TeV center-of-mass energies provide unprecedented sensitivity to heavy leptophilic $Z^{'}$ bosons. Moreover, if these $U (1)$ models are classically scale-invariant, the phase transition at the $U (1)$ symmetry-breaking scale tends to be strongly first-order with ultra-supercooling, and leads to observable stochastic gravitational wave signatures. We find that the future sensitivity of gravitational wave observatories, such as advanced LIGO-VIRGO and Cosmic Explorer, can be complementary to the collider experiments, probing higher $Z^{'}$ masses up to $O (1 0^{4} TeV)$ , while being consistent with naturalness and perturbativity considerations.
hep-phastro-ph.COhep-exJHEP(2023)·43 citations
15*
Next-to-soft radiation from a different angle
Melissa van Beekveld🇬🇧 · Abhinava Danish🇮🇳 · Eric Laenen🇳🇱 · Sourav Pal🇮🇳 · Anurag Tripathi🇮🇳 · Chris D. White🇬🇧
Soft and collinear radiation in collider processes can be described in a universal way, that is independent of the underlying process. Recent years have seen a number of approaches for probing whether radiation beyond the leading soft approximation can also be systematically classified. In this paper, we study a formula that captures the leading next-to-soft QCD radiation affecting processes with both final- and initial-state partons, by shifting the momenta in the non-radiative squared amplitude. We first examine W+jet production, and show that a previously derived formula of this type indeed holds in the case in which massive colour singlet particles are present in the final state. Next, we develop a physical understanding of the momentum shifts, showing precisely how they disrupt the well-known angular ordering property of leading soft radiation.
hep-phPRD(2024)·12 citations
16*
Low Fine-Tuning with Heavy Higgsinos in Yukawa Unified SUSY GUTs
Cem Salih Un🇹🇷
The work presented considers a class of minimally constructed Yukawa unified SUSY GUTs - NUHM2 - and explore their implications when their soft supersymmetry breaking Lagrangian is generalized by the non-holomorphic terms which provide extra contributions to the Higgsino mass and couple the supersymmetric scalar fields to the wrong Higgs doublets. With such a simple extension, it can be found several regions with interesting implications which cannot be realized in the usual restricted models. It is observed that the Yukawa unification solutions can be compatible with relatively light mass spectrum and acceptable low fine-tuning measurements. In the restricted models such effects can directly be addressed to the non-holomorphic terms. They can provide a slight improvement in the SM-like Higgs boson mass without altering the mass spectrum too much, and they can accommodate relatively lighter sbottom and stau masses, while they do not change the stop sector much. The dark matter can be Higgsino-like or Bino-like, but the experimental relic density measurements favor the Higgsino-like dark matter, while the Bino-like dark matter is predicted with a quite large relic density. Also several coannihilation scenarios are identified in the Higgsino-like dark matter regions, while the Bino-like dark matter do not allow any of such coannihilation processes. The presence of the non-holomorphic terms can weaken the impact from the phenomenological or indirect constraints such as low fine-tuning, Yukawa unification and rare decays of $B -$ meson, the direct and model independent constraints still yield a strong strike on the solutions. Such constraints are discussed in regard of the current collider analyses on $τ τ$ events and direct detection of dark matter experiments.
hep-phTurk.J.Phys.(2024)·7 citations
17*
Phantom fluid cosmology: Impact of a phantom hidden sector on cosmological observables
James M. Cline🇨🇦 · Matteo Puel🇨🇦 · Takashi Toma🇯🇵 · Qiu Shi Wang🇨🇦
Phantom scalar theories are widely considered in cosmology, but rarely at the quantum level, where they give rise to negative-energy ghost particles. These cause decay of the vacuum into gravitons and photons, violating observational gamma-ray limits unless the ghosts are effective degrees of freedom with a cutoff $Λ$ at the few-MeV scale. We update the constraints on this scale, finding that $Λ ≲ 19$ MeV. We further explore the possible coupling of ghosts to a light, possibly massless, hidden sector particle, such as a sterile neutrino. Vacuum decays can then cause the dark matter density of the universe to grow at late times. The combined phantom plus dark matter fluid has an effective equation of state $w < - 1$ , and functions as a new source of dark energy. We derive constraints from cosmological observables on the rate of vacuum decay into such a phantom fluid. We find a mild preference for the ghost model over the standard cosmological one, and a modest amelioration of the Hubble and $S_{8}$ tensions.
hep-phastro-ph.COPRD(2023)·15 citations
18*
Upper bound on the Atiyah-Singer index from tadpole cancellation
Keiya Ishiguro🇯🇵 · Takafumi Kai🇯🇵 · Satsuki Nishimura🇯🇵 · Hajime Otsuka🇯🇵 · Maki Takeuchi🇯🇵
We propose an upper bound on the Atiyah-Singer index in the effective action of string theory. For $E_{8} \times E_{8}^{'}$ and $S O (32)$ heterotic string theories on smooth Calabi-Yau threefolds with line bundles, we find that the tadpole cancellation and supersymmetry conditions lead to an upper bound on the generation number of quarks and leptons as well as Higgs doublets. By taking into account the observed value of four-dimensional gauge couplings and the supergravity approximation, we explicitly evaluate the bound on favorable complete intersection Calabi-Yau threefolds. The bound can be extended to Calabi-Yau threefolds in the Kreuzer-Skarke database. We also put the upper bound on the Atiyah-Singer index in Type IIB/F-theory compactifications.
↳ hep-thhep-phJHEP(2020)·6 citations
19*
Pion Transition Form Factor from Twisted-Mass Lattice QCD and the Hadronic Light-by-Light $π^{0}$ -pole Contribution to the Muon $g - 2$
C. Alexandrou🇨🇾 · S. Bacchio🇨🇾 · G. Bergner🇩🇪 · S. Burri🇨🇭 · J. Finkenrath🇨🇾 · A. Gasbarro🇨🇭 · K. Hadjiyiannakou🇨🇾 · K. Jansen🇩🇪 · G. Kanwar🇨🇭 · B. Kostrzewa🇩🇪 · G. Koutsou🇨🇾 · K. Ottnad🇩🇪 and 5 other authors
The neutral pion generates the leading pole contribution to the hadronic light-by-light tensor, which is given in terms of the nonperturbative transition form factor $F_{π^{0} γ γ} (q_{1}^{2}, q_{2}^{2})$ . Here we present an ab-initio lattice calculation of this quantity in the continuum and at the physical point using twisted-mass lattice QCD. We report our results for the transition form factor parameterized using a model-independent conformal expansion valid for arbitrary space-like kinematics and compare it with experimental measurements of the single-virtual form factor, the two-photon decay width, and the slope parameter. We then use the transition form factors to compute the pion-pole contribution to the hadronic light-by-light scattering in the muon $g - 2$ , finding $a_{μ}^{π^{0} -pole} = 56.7 (3.2) \times 1 0^{- 11}$ .
↳ hep-lathep-phPRD(2023)·34 citations
20*
The Compton-Pair telescope: A prototype for a next-generation MeV $γ$ -ray observatory
Janeth Valverde (UMBC/NASA GSFC)🇺🇸 · Nicholas Kirschner (GWU)🇺🇸 · Zachary Metzler (UMD/CRESST II/NASA GSFC)🇺🇸 · Lucas D. Smith (UMD)🇺🇸 · Nicholas Cannady (CRESST/UMBC)🇺🇸 · Regina Caputo (GSFC)🇺🇸 · Carolyn Kierans (GSFC)🇺🇸 · Iker Liceaga-Indart (GSFC/Catholic U)🇺🇸 · Alexander Moiseev (CRESST/UMD)🇺🇸 · Lucas Parker (LANL)🇺🇸 · Makoto Sasaki (CRESST/UMD)🇺🇸 · Adam Schoenwald (GSFC/UMBC)🇺🇸 and 22 other authors
The Compton Pair (ComPair) telescope is a prototype that aims to develop the necessary technologies for future medium energy gamma-ray missions and to design, build, and test the prototype in a gamma-ray beam and balloon flight. The ComPair team has built an instrument that consists of 4 detector subsystems: a double-sided silicon strip detector Tracker, a novel high-resolution virtual Frisch-grid cadmium zinc telluride Calorimeter, and a high-energy hodoscopic cesium iodide Calorimeter, all of which are surrounded by a plastic scintillator anti-coincidence detector. These subsystems together detect and characterize photons via Compton scattering and pair production, enable a veto of cosmic rays, and are a proof-of-concept for a space telescope with the same architecture. A future medium-energy gamma-ray mission enabled through ComPair will address many questions posed in the Astro2020 Decadal survey in both the New Messengers and New Physics and the Cosmic Ecosystems themes. In this contribution, we will give an overview of the ComPair project and steps forward to the balloon flight.
↳ astro-ph.IMhep-exhep-phPoS(2023)·5 citations
21*
Embedding Ultra slow-roll inflaton dynamics in Warm Inflation
Sandip Biswas🇮🇳 · Kaushik Bhattacharya🇮🇳 · Suratna Das🇮🇳
Slow-roll of the inflaton field defines the standard dynamics of the inflationary epoch. However, the inflationary system deviates from slow-roll when it encounters an extremely flat region of the inflaton potential, and enters a phase dubbed Ultra slow roll. In this article, we explore the possibility of realizing an Ultra slow-roll phase in a particularly interesting inflationary scenario, called Warm Inflation. In the Warm inflationary scenario a thermalized, sub-dominant radiation bath coexists with the inflaton energy density as an effect of dissipative dynamics. We show in this article that though the background dynamics indicate Ultra slow-roll when the potential becomes extremely flat, in Warm Inflation models, where the dissipation coefficient is a sole function of the temperature of the radiation bath, the system fails to maintain the thermal equilibrium as soon as it enters the Ultra slow-roll phase. As thermal equilibrium is a key feature of Warm Inflation, and as it is not yet known how to deal with Warm Inflation without thermal equilibrium, we could not analyze such systems any further in this article. However, we demonstrate that brief periods of Ultra slow-roll phase, which smoothly ends into standard slow-roll, can be accommodated in WI models where the dissipation coefficient is not only a function of the temperature of the radiation bath but also depends on the amplitude of the inflaton field. We theoretically determine the criteria of successfully embedding Ultra slow-roll in WI while the system remain in thermal equilibrium, and also demonstrate numerically that such short Ultra slow-roll phases can indeed be embedded in specific Warm Inflation models which comply with the theoretically determined criteria.
↳ astro-ph.COgr-qchep-phPRD(2024)·11 citations
22*
Jet energy calibration with deep learning as a Kubeflow pipeline
Daniel Holmberg🇺🇸 · Dejan Golubovic🇨🇭 · Henning Kirschenmann🇫🇮
Precise measurements of the energy of jets emerging from particle collisions at the LHC are essential for a vast majority of physics searches at the CMS experiment. In this study, we leverage well-established deep learning models for point clouds and CMS open data to improve the energy calibration of particle jets. To enable production-ready machine learning based jet energy calibration an end-to-end pipeline is built on the Kubeflow cloud platform. The pipeline allowed us to scale up our hyperparameter tuning experiments on cloud resources, and serve optimal models as REST endpoints. We present the results of the parameter tuning process and analyze the performance of the served models in terms of inference time and overhead, providing insights for future work in this direction. The study also demonstrates improvements in both flavor dependence and resolution of the energy response when compared to the standard jet energy corrections baseline.
↳ hep-exhep-phphysics.data-anComput.Softw.Big Sci.(2023)·7 citations
23*
Neutron Scattering off One-Neutron Halo Nuclei in Halo Effective Field Theory
Xu Zhang🇨🇳 · Hai-Long Fu🇨🇳 · Feng-Kun Guo🇨🇳 · Hans-Werner Hammer🇩🇪
Neutron scattering off neutron halos can provide important information about the internal structure of nuclei close to the neutron drip line. In this work, we use halo effective field theory to study the $s$ -wave scattering of a neutron and the spin-parity $J^{P} = \frac{1}{2}^{+}$ one-neutron halo nuclei $^{11} Be$ , $^{15} C$ , and $^{19} C$ at leading order. In the $J = 1$ channel, the only inputs to the Faddeev equations are their one-neutron separation energies. In the $J = 0$ channel, the neutron-neutron scattering length and the two-neutron separation energies of $^{12} Be$ , $^{16} C$ and $^{20} C$ enter as well. The numerical results show that the total $s$ -wave cross sections in the $J = 1$ channel at threshold are of the order of a few barns. In the $J = 0$ channel, these cross sections are of the order of a few barns for $n$ - $^{11} Be$ and $n$ - $^{19} C$ scattering, and about 60 $mb$ for the $n$ - $^{15} C$ scattering. The appearance of a pole in $p cot δ$ close to zero in all three cases indicates the existence of a virtual Efimov state close to threshold in each of the $^{12} Be$ , $^{16} C$ , and $^{20} C$ systems. Observation of this pole would confirm the presence of Efimov physics in halo nuclei. The dependence of the results on the neutron-core scattering length is also studied.
↳ nucl-thhep-phnucl-exPRC(2023)·8 citations
24*
Graviton detection and the quantization of gravity
Daniel Carney🇺🇸 · Valerie Domcke🇨🇭 · Nicholas L. Rodd🇨🇭
We revisit a question asked by Dyson: "Is a graviton detectable?" We demonstrate that in both Dyson's original sense and in a more modern measurement-theoretic sense, it is possible to construct a detector sensitive to single gravitons, and in fact a variety of existing and near-term gravitational wave detectors can achieve this. However, while such a signal would be consistent with the quantization of the gravitational field, we draw on results from quantum optics to show how the same signal could just as well be explained via classical gravitational waves. We outline the kind of measurements that would be needed to demonstrate quantization of gravitational radiation and explain why these are substantially more difficult than simply counting graviton clicks or observing gravitational noise in an interferometer, and likely impossible to perform in practice.
↳ hep-thastro-ph.COgr-qchep-ph+1PRD(2024)·89 citations
25*
Birth of the first stars amidst decaying and annihilating dark matter
Wenzer Qin🇺🇸 · Julian B. Munoz🇺🇸 · Hongwan Liu🇺🇸 · Tracy R. Slatyer🇺🇸
The first stars are expected to form through molecular-hydrogen (H $_{2}$ ) cooling, a channel that is especially sensitive to the thermal and ionization state of gas, and can thus act as a probe of exotic energy injection from decaying or annihilating dark matter (DM). Here, we use a toy halo model to study the impact of DM-sourced energy injection on the H $_{2}$ content of the first galaxies, and thus estimate the threshold mass required for a halo to form stars at high redshifts. We find that currently allowed DM models can significantly change this threshold, producing both positive and negative feedback. In some scenarios, the extra heating of the gas raises the halo mass required for collapse, whereas in others, energy injection lowers the threshold by increasing the free-electron fraction and catalyzing H $_{2}$ formation. The direction of the effect can be redshift-dependent. We also bracket the uncertainties from self-shielding of halos from Lyman-Werner radiation. Hence, exotic energy injection can both delay and accelerate the onset of star formation; we show how this can impact the timing of 21cm signals at cosmic dawn. We encourage detailed simulation follow-ups in the most promising regions of parameter space identified in this work.
↳ astro-ph.COastro-ph.GAhep-phPRD(2024)·29 citations
26*
Anomaly Enforced Gaplessness and Symmetry Fractionalization for $S p i n_{G}$ Symmetries
T. Daniel Brennan🇺🇸
Symmetries and their anomalies give strong constraints on renormalization group (RG) flows of quantum field theories. Recently, the identification of a theory's global symmetries with its topological sector has provided additional constraints on RG flows to symmetry preserving gapped phases due to mathematical results in category and topological quantum field theory. In this paper, we derive constraints on RG flows from $Z_{2}$ -valued pure- and mixed-gravitational anomalies that can only be activated on non-spin manifolds. We show that such anomalies cannot be matched by a unitary, symmetry preserving gapped phase without symmetry fractionalization. In particular, we discuss examples that commonly arise in $4 d$ gauge theories with fermions.
↳ hep-thcond-mat.str-elhep-phmath-ph+1JHEP(2024)·13 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.