Mass Threshold Research Articles

Improving methods and predictions at high-energy e+e− colliders within collinear factorisation

We illustrate how electron Parton Distribution Functions (PDFs) with next-to-leading collinear logarithmic accuracy must be employed in the context of perturbative predictions for high-energy e+e−-collision processes. In particular, we discuss how the renormalisation group equation evolution of such PDFs is affected by the presence of multiple fermion families and their respective mass thresholds, and by the dependences on the choices of the factorisation and renormalisation schemes. We study the impact of the uncertainties associated with the PDFs on physical cross sections, in order to arrive at realistic precision estimates for observables computed with collinear-factorisation formulae. We do so by presenting results for the production of a heavy neutral object as well as for toverline{t} and W+W− pairs, including next-to-leading-order effects of electroweak origin.

QCD sum rule study for hidden-strange pentaquarks* *Supported by the National Natural Science Foundation of China (12175318), the National Key R & D Program of China (2020YFA0406400) and the Fundamental Research Funds for the Central Universities

Inspired by the LHCb observations of hidden-charm states, we study their hidden-strange analog states in both the and configurations. We investigate pentaquark states in the , , , , and structures with and and with and calculate their masses in the framework of QCD sum rules. Our numerical results show that the extracted hadron masses for all the , , , , and structures are significantly higher than the mass threshold, and the masses for and are also higher than the threshold of the corresponding hadron; hence, no bound state exists in such channels, which is consistent with the current experimental status.

The hydrogen clock to infer the upper stellar mass

ABSTRACT The most massive stars dominate the chemical enrichment, mechanical and radiative feedback, and energy budget of their host environments. Yet how massive stars initially form and how they evolve throughout their lives is ambiguous. The mass loss of the most massive stars remains a key unknown in stellar physics, with consequences for stellar feedback and populations. In this work, we compare grids of very massive star (VMS) models with masses ranging from 80 to 1000 M⊙, for a range of input physics. We include enhanced winds close to the Eddington limit as a comparison to standard O-star winds, with consequences for present-day observations of ∼50–100 M⊙ stars. We probe the relevant surface H abundances (Xs) to determine the key traits of VMS evolution compared to O stars. We find fundamental differences in the behaviour of our models with the enhanced-wind prescription, with a convergence on the stellar mass at 1.6 Myr, regardless of the initial mass. It turns out that Xs is an important tool in deciphering the initial mass due to the chemically homogeneous nature of VMS above a mass threshold. We use Xs to break the degeneracy of the initial masses of both components of a detached binary, and a sample of WNh stars in the Tarantula Nebula. We find that for some objects, the initial masses are unrestricted and, as such, even initial masses of the order 1000 M⊙ are not excluded. Coupled with the mass turnover at 1.6 Myr, Xs can be used as a ‘clock’ to determine the upper stellar mass.

QED radiative corrections for accelerator neutrinos

Neutrino oscillation experiments at accelerator energies aim to establish charge-parity violation in the neutrino sector by measuring the energy-dependent rate of νe appearance and νμ disappearance in a νμ beam. These experiments can precisely measure νμ cross sections at near detectors, but νe cross sections are poorly constrained and require theoretical inputs. In particular, quantum electrodynamics radiative corrections are different for electrons and muons. These corrections are proportional to the small quantum electrodynamics coupling α ≈ 1/137; however, the large separation of scales between the neutrino energy and the proton mass (~GeV), and the electron mass and soft-photon detection thresholds (~MeV) introduces large logarithms in the perturbative expansion. The resulting flavor differences exceed the percent-level experimental precision and depend on nonperturbative hadronic structure. We establish a factorization theorem for exclusive charged-current (anti)neutrino scattering cross sections representing them as a product of two factors. The first factor is flavor universal; it depends on hadronic and nuclear structure and can be constrained by high-statistics νμ data. The second factor is non-universal and contains logarithmic enhancements, but can be calculated exactly in perturbation theory. For charged-current elastic scattering, we demonstrate the cancellation of uncertainties in the predicted ratio of νe and νμ cross sections. We point out the potential impact of non-collinear energetic photons and the distortion of the visible lepton spectra, and provide precise predictions for inclusive observables.

Evaluation of Nutritional Characteristics Reveals Similar Prevalence of Malnutrition in Patients with Ulcerative Colitis and Crohn's Disease.

Inflammatory bowel disease (IBD) is associated with an increased risk of malnutrition and sarcopenia. To evaluate the nutritional status of patients with IBD and determine the threshold values of different parameters of nutritional assessment to identify malnutrition. This was a single-centre cross-sectional analysis of adult patients with IBD [ulcerative colitis (UC) and Crohn's disease (CD)] who underwent anthropometry [body mass index (BMI), mid upper arm circumference (MUAC) and triceps-fold thickness (TSF)], body composition analysis and assessment for sarcopenia [hand-grip strength and skeletal muscle index (SMI) at L3 vertebral level)]. Age- and gender-matched healthy adults served as controls. Malnutrition was defined according to the European Society of Clinical Nutrition and Metabolism (ESPEN) criteria. A total of 406 patients [336 (82.76%) UC and 70 (17.24%) CD; mean age 40.56 ± 13.67years; 215 (52.95%) males] with IBD and 100 healthy controls (mean age 38.69 ± 10.90years; 56 (56%) males) were enrolled. The mean BMI, MUAC, TSF thickness, fat and lean mass, hand-grip strength, and SMI at L3 vertebral level were lower in patients with IBD compared to controls. The prevalence of malnutrition was similar in UC and CD [24.40% (n = 82) and 28.57% (n = 20), respectively (p = 0.46)]. Thresholds for fat mass in females (15.8kg) and visceral fat index in males (0.26) were both sensitive and specific to detect malnutrition. The cutoff values of MUAC and TSF thickness to identify malnutrition were 23.25cm and 25.25cm, and 16.50mm and 8.50mm, in females and males, respectively. Malnutrition and sarcopenia were common in patients with IBD, with the prevalence being similar in patients with both UC and CD.

Elucidating galaxy assembly bias in SDSS

We investigate the level of galaxy assembly bias in the Sloan Digital Sky Survey (SDSS) main galaxy sample using ELUCID, a state-of-the-art constrained simulation that accurately reconstructed the initial density perturbations within the SDSS volume. On top of the ELUCID haloes, we develop an extended HOD model that includes the assembly bias of central and satellite galaxies, parameterized as $\mathcal{Q}_\mathrm{cen}$ and $\mathcal{Q}_\mathrm{sat}$, respectively, to predict a suite of one- and two-point observables. In particular, our fiducial constraint employs the probability distribution of the galaxy number counts measured on $8\,\mathrm{Mpc}\,h^{-1}$ scales $N_8^g$ and the projected cross-correlation functions of quintiles of galaxies selected by $N_8^g$ with our entire galaxy sample. We perform extensive tests of the efficacy of our method by fitting the same observables to mock data using both constrained and non-constrained simulations. We discover that in many cases the level of cosmic variance between the two simulations can produce biased constraints that lead to an erroneous detection of galaxy assembly bias if the non-constrained simulation is used. When applying our method to the SDSS data, the ELUCID reconstruction effectively removes an otherwise strong degeneracy between cosmic variance and galaxy assembly bias in SDSS, enabling us to derive an accurate and stringent constraint on the latter. Our fiducial ELUCID constraint, for galaxies above a stellar mass threshold $M_*{=}10^{10.2}\,h^{-2}\,M_\odot$, is $\mathcal{Q}_\mathrm{cen}{=}{-}0.09\pm{0.05}$ and $\mathcal{Q}_\mathrm{sat}{=}0.09\pm{0.10}$, indicating no evidence for a significant~($>2\sigma$) galaxy assembly bias in the local Universe probed by SDSS. Finally, our method provides a promising path to the robust modelling of the galaxy-halo connection within future surveys like DESI and PFS.

Roles of a0(980) , Λ(1670) , and Σ(1385) in the Λc+→ηΛπ+ decay

Recently, the Belle Collaboration has measured the ${\mathrm{\ensuremath{\Lambda}}}_{c}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+}$ decay and reported the $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and $\mathrm{\ensuremath{\Lambda}}{\ensuremath{\pi}}^{+}$ invariant mass distributions, which show the clear signals of the resonances $\mathrm{\ensuremath{\Lambda}}(1670)$ and $\mathrm{\ensuremath{\Sigma}}(1385)$, respectively. Based on our previous works [Eur. Phys. J. C 76, 496 (2016) and Phys. Rev. D 95, 074024 (2017)], we reanalyze this process by considering the $S$-wave $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and $\ensuremath{\eta}{\ensuremath{\pi}}^{+}$ final state interactions within the chiral unitary approach, which dynamically generate the $\mathrm{\ensuremath{\Lambda}}(1670)$ and ${a}_{0}(980)$, respectively. Our results are in agreement with the Belle measurements of the $\ensuremath{\eta}\mathrm{\ensuremath{\Lambda}}$ and ${\ensuremath{\pi}}^{+}\mathrm{\ensuremath{\Lambda}}$ invariant mass distributions. In addition, the ${\ensuremath{\pi}}^{+}\ensuremath{\eta}$ invariant mass distribution is also calculated and a cusp structure of ${a}_{0}(980)$ is clearly shown around the $K\overline{K}$ mass threshold.

Impact of the turnover in the high-z galaxy luminosity function on the 21-cm signal during Cosmic Dawn and Epoch of Reionization

ABSTRACT The shape of the faint-end of the high-z galaxy luminosity function (LF) informs early star formation and reionization physics during the Cosmic Dawn and Epoch of Reionization. Until recently, based on the strong gravitational lensing cluster deep surveys, the Hubble Frontier Fields (HFF) has found a potential turnover in the ultraviolet (UV) LF at $\mathit{ z}$ ∼ 6. In this paper, we analyse the contribution of extremely faint galaxies with the magnitude larger than the turnover magnitude in LF to cosmic reionization. We apply the measurement from HFF to our suppressed star formation efficiency model, including three free parameters: halo mass threshold Mt, curvature parameter β, and a UV conversion factor lUV. According to our fit of 68 per cent confidence level, the high-redshift star formation in haloes smaller than $M_t=1.82^{+2.86}_{-1.08}\times 10^{10} \, \rm M_{\odot }$ is found to be dampened. The turnover magnitude $\rm \gtrsim -13.99-2.45$, correspondingly the halo mass $\lesssim (4.57+20.03)\times 10^{9} \, \rm M_{\odot }$. We find that the absorption trough in the global 21-cm signal is sensitive to our SFE model parameters. Together with (β, lUV) = ($2.17^{+2.42}_{-1.72}$, $9.33^{+0.43}_{-0.42} \, \rm ~erg~yr ~s^{-1}\, M_{\odot }^{-1})$, the trough locates at ∼$134^{+10}_{-17}$$\rm MHz$ with an amplitude of ∼$-237^{-6}_{+7}$$\rm mK$, compared to (106 MHz, -212 mK) in the absence of turnover. Besides, we find that the star formation of faint galaxies has also an impact on the 21-cm power spectra. The best-fitting peak power decreases by$\sim 4{{\ \rm per\ cent}}$ and shifts towards smaller scales from $0.88 \, h\, \rm Mpc^{-1}$ to $0.91 \, h\, \rm Mpc^{-1}$. According to our calculation, such impact is distinguishable with the forthcoming Square Kilometre Array.

Investigating the mass-ratio dependence of the prompt-collapse threshold with numerical-relativity simulations

The next observing runs of advanced gravitational-wave detectors will lead to a variety of binary neutron star detections and numerous possibilities for multimessenger observations of binary neutron star systems. In this context a clear understanding of the merger process and the possibility of prompt black hole formation after merger is important, as the amount of ejected material strongly depends on the merger dynamics. These dynamics are primarily affected by the total mass of the binary, however, the mass ratio also influences the postmerger evolution. To determine the effect of the mass ratio, we investigate the parameter space around the prompt-collapse threshold with a new set of fully relativistic simulations. The simulations cover three equations of state and seven mass ratios in the range of $1.0\ensuremath{\le}q\ensuremath{\le}1.75$, with five to seven simulations of binary systems of different total mass in each case. The threshold mass is determined through an empirical relation based on the collapse time, which allows us to investigate effects of the mass ratio on the threshold mass and also on the properties of the remnant system. Furthermore, we model effects of mass ratio and equation of state on tidal parameters of threshold configurations.

Probing the z ≳ 6 quasars in a universe with IllustrisTNG physics: impact of gas-based black hole seeding models

ABSTRACT We explore implications of a range of black hole (BH) seeding prescriptions on the formation of the brightest $z$ ≳ 6 quasars in cosmological hydrodynamic simulations. The underlying galaxy formation model is the same as in the IllustrisTNG simulations. Using constrained initial conditions, we study the growth of BHs in rare overdense regions (forming $\gtrsim 10^{12}\, {\rm M}_{\odot }\,h^{-1}$ haloes by $z$ = 7) using a (9 Mpc h−1)3 simulated volume. BH growth is maximal within haloes that are compact and have a low tidal field. For these haloes, we consider an array of gas-based seeding prescriptions wherein $M_{\mathrm{seed}}=10^4\!-\!10^6\, {\rm M}_{\odot }\,h^{-1}$ seeds are inserted in haloes above critical thresholds for halo mass and dense, metal-poor gas mass (defined as $\tilde{M}_{\mathrm{h}}$ and $\tilde{M}_{\mathrm{sf,mp}}$, respectively, in units of Mseed). We find that a seed model with $\tilde{M}_{\mathrm{sf,mp}}=5$ and $\tilde{M}_{\mathrm{h}}=3000$ successfully produces a $z$ ∼ 6 quasar with $\sim 10^9\, {\rm M}_{\odot }$ mass and ∼1047 erg s−1 luminosity. BH mergers play a crucial role at $z$ ≳ 9, causing an early boost in BH mass at a time when accretion-driven BH growth is negligible. With more stringent seeding conditions (e.g. $\tilde{M}_{\mathrm{sf,mp}}=1000$), the relative paucity of BH seeds results in a much lower merger rate. In this case, $z$ ≳ 6 quasars can only be formed if we enhance the maximum allowed BH accretion rates (by factors ≳10) compared to the accretion model used in IllustrisTNG. This can be achieved either by allowing for super-Eddington accretion, or by reducing the radiative efficiency. Our results demonstrate that progenitors of $z$ ∼ 6 quasars have distinct BH merger histories for different seeding models, which will be distinguishable with Laser Interferometer Space Antenna observations.

COSMOS2020: Cosmic evolution of the stellar-to-halo mass relation for central and satellite galaxies up to z ∼ 5

We used the COSMOS2020 catalog to measure the stellar-to-halo mass relation (SHMR) divided by central and satellite galaxies from z = 0.2 to z = 5.5. Starting from accurate photometric redshifts, we measured the near-infrared selected two-point angular correlation and stellar mass functions in ten redshift bins. We used a phenomenological model that parametrizes the stellar-to-halo mass relation for central galaxies and the number of galaxies inside each halo to describe our observations. This model qualitatively reproduces our measurements and their dependence on the stellar mass threshold. Surprisingly, the mean halo occupation distribution only shows a mild evolution with redshift suggesting that galaxies occupy halos similarly throughout cosmic time. At each redshift, we measured the ratio of stellar mass to halo mass, M*/Mh, which shows the characteristic strong dependence of halo mass with a peak at Mhpeak ∼ 2 × 1012 M⊙. For the first time, using a joint modeling of clustering and abundances, we measured the evolution of Mhpeak from z = 0.2 to z = 5.5. Mhpeak increases gradually with redshift from log Mhpeak/M⊙ ∼ 12.1 at z ∼ 0.3 to log Mhpeak/M⊙ ∼ 12.3 at z ∼ 2, and up to log Mhpeak/M⊙ ∼ 12.9 at z ∼ 5. Similarly, the stellar mass peak M∗peak increases with redshift from log M∗peak/M⊙ ∼ 10.5 at z ∼ 0.3 to log M∗peak/M⊙ ∼ 10.9 at z ∼ 3. The SHMR ratio at the peak halo mass remains almost constant with redshift. These results are in accordance with the scenario in which the peak of star-formation efficiency moves toward more massive halos at higher redshifts. We also measured the fraction of satellites as a function of stellar mass and redshift. For all stellar mass thresholds, the satellite fraction decreases at higher redshifts. At a given redshift, there is a higher fraction of low-mass satellites and this fraction reaches a plateau at ∼25% at z ∼ 1. The satellite contribution to the total stellar mass budget in halos becomes more important than that of the central at halo masses of about Mh > 1013 M⊙ and always stays below the peak, indicating that quenching mechanisms are present in massive halos that keep the star-formation efficiency low. Finally, we compared our results with three hydrodynamical simulations: HORIZON-AGN, TNG100 of the ILLUSTRISTNG project, and EAGLE. We find that the most significant discrepancy is at the high-mass end, where the simulations generally show that satellites have a higher contribution to the total stellar mass budget than the observations. This, together with the finding that the fraction of satellites is higher in the simulations, indicates that the feedback mechanisms acting in both group- and cluster-scale halos appear to be less efficient in quenching the mass assembly of satellites – and that quenching occurs much later in the simulations.

Satellite mass functions and the faint end of the galaxy mass–halo mass relation in LCDM

ABSTRACT The abundance of the faintest galaxies provides insight into the nature of dark matter and the process of dwarf galaxy formation. In the LCDM scenario, low-mass haloes are so numerous that the efficiency of dwarf formation must decline sharply with decreasing halo mass in order to accommodate the relative scarcity of observed dwarfs and satellites in the Local Group. The nature of this decline contains important clues to the mechanisms regulating the onset of galaxy formation in the faintest systems. We explore here two possible models for the stellar mass (M*)–halo mass (M200) relation at the faint end, motivated by some of the latest LCDM cosmological hydrodynamical simulations. One model includes a sharp mass threshold below which no luminous galaxies form, as expected if galaxy formation proceeds only in systems above the hydrogen-cooling limit. In the second model, M* scales as a steep power law of M200 with no explicit cut-off, as suggested by recent semi-analytical work. Although both models predict satellite numbers around Milky Way-like galaxies consistent with current observations, they predict vastly different numbers of ultrafaint dwarfs and of satellites around isolated dwarf galaxies. Our results illustrate how the satellite mass function around dwarfs may be used to probe the M*–M200 relation at the faint end and to elucidate the mechanisms that determine which low-mass haloes ‘light up’ or remain dark in the LCDM scenario.

Updated constraints on WIMP dark matter annihilation by radio observations of M31

The present work derived the robust constraints on annihilating WIMP parameters utilizing new radio observations of M31, as well as new studies of its dark matter distribution and other properties. The characteristics of emission due to DM annihilation were computed in the frame of 2D galactic model employing GALPROP code adapted specifically for M31. This enabled us to refine various inaccuracies of previous studies on the subject. DM constraints were obtained for two representative annihilation channels: $\chi\chi \rightarrow b\overline{b}$ and $\chi\chi \rightarrow \tau^+\tau^-$. A wide variety of radio data was utilized in the frequency range $\approx$(0.1--10) GHz. As the result the thermal WIMP lighter than fiducially $\approx$ 70 GeV for $b\overline{b}$ channel and $\approx$ 40 GeV for $\tau^+\tau^-$ was excluded. The corresponding mass threshold uncertainty ranges were estimated to be 20--210 GeV and 18--89 GeV. The obtained exclusions are competitive to those from Fermi-LAT observations of dwarfs and AMS-02 measurements of antiprotons. Our constraints do not exclude the explanation of the gamma-ray outer halo of M31 and the Galactic center excess by annihilating DM. The thermal WIMP with $m_x \approx 70$ GeV, which explains the outer halo, would make a significant contribution to the non-thermal radio flux in M31 nucleus, fitting well both the spectrum and morphology. And, finally, we questioned the possibility claimed in other studies to robustly constrain heavy thermal WIMP with $m_x > 100$ GeV by radio data on M31.

Signature of a Doubly Charm Tetraquark Pole in DD^{*} Scattering on the Lattice.

The doubly charm tetraquark with flavor ccu[over ¯]d[over ¯] and isospin I=0 is investigated by calculating the DD^{*} scattering amplitude with lattice QCD. The simulation is done on CLS ensembles with dynamical u/d, s quarks and m_{π}≃280 MeV for two charm quark masses, one slightly larger and one slightly lower than the physical value. The scattering amplitudes for partial waves l=0, 1 are extracted near threshold via the Lüscher method by considering systems with total momenta PL/(2π)=0,1,sqrt[2],2 on two spatial volumes. A virtual bound state pole in the DD^{*} scattering amplitude with l=0 is found 9.9_{-7.1}^{+3.6} MeV below the DD^{*} threshold for the charm quark mass closer to the physical value. This pole is likely related to the doubly charm tetraquark discovered by LHCb less than 1MeV below the D^{0}D^{*+} threshold. Future lattice simulations closer to the continuum limit and physical quark masses would be valuable to establish this connection systematically.

Improved indirect limits on charm and bottom quark EDMs

We derive indirect limits on the charm and bottom quark electric dipole moments (EDMs) from paramagnetic AMO and neutron EDM experiments. The charm and bottom quark EDMs generate CP-odd photon-gluon operators and light quark EDMs at the c- and b-quark mass thresholds. These CP-odd operators induce the CP-odd semi-leptonic operator CS and the neutron EDM below the QCD scale that are probed by the paramagnetic and neutron EDM experiments, respectively. The bound from CS is |dc| < 1.3 × 10−20e cm for the charm quark and |db| < 7.6 × 10−19e cm for the bottom quark, with its uncertainty estimated as 10 %. The neutron EDM provides a stronger bound, |dc| < 6 × 10−22e cm and |db| < 2 × 10−20e cm, though with a larger hadronic uncertainty.

Mass gain and stopover dynamics among migrating songbirds are linked to seasonal, environmental, and life-history effects

Abstract During migration, birds must stopover at refueling sites to replenish energy stores, with the rate of refueling linked to stopover length, migration speed, and the timing of critical life stages, such as breeding. Under optimal migration theory, birds are expected to maximize fuel intake and minimize stopover length (the time minimization hypothesis). Within a multi-species framework, we demonstrate that time minimization behavior is context-dependent, as refueling rate, stopover length, and departure decisions vary between seasons, among species with different ecological traits (e.g., diet and migration distance), and in response to density-dependent factors and prevailing environmental conditions. Using long-term banding data (10 years) from southwestern British Columbia, Canada, we investigated the ecological processes shaping stopover dynamics among 5 warbler (Parulidae) and 5 sparrow species (Passerellidae). Specifically, we assessed variation in fuel deposition rates (FDRs) as well as the associations between mass gain, stopover length, and departure probability. FDR was greater in insectivorous warblers during spring migration and in species migrating long distances. FDR responded positively to temperature and habitat productivity, but negatively to precipitation events, particularly for insectivorous, long-distance migrants during spring migration. Similarly, density-dependent refueling rate was only observed in insectivores and long-distance migrants during spring migration, where higher densities of foliage-gleaning insectivores were associated with a lower FDR. Stopover duration was more closely associated with body condition upon arrival and subsequent mass gain than direct environmental effects, especially during northward spring migration, providing support for time minimization and a mass threshold influencing departure decisions. These results highlight that refueling rates and stopover quality vary among species depending on their life-history strategies, with particular implications for long-distance, migratory insectivores, which may be most susceptible to climate shifts.

Study of the doubly charmed tetraquark {{{{{{rm{T}}}}}}}_{{{{{{rm{c}}}}}}{{{{{rm{c}}}}}}}^{+}

Quantum chromodynamics, the theory of the strong force, describes interactions of coloured quarks and gluons and the formation of hadronic matter. Conventional hadronic matter consists of baryons and mesons made of three quarks and quark-antiquark pairs, respectively. Particles with an alternative quark content are known as exotic states. Here a study is reported of an exotic narrow state in the D0D0π+ mass spectrum just below the D*+D0 mass threshold produced in proton-proton collisions collected with the LHCb detector at the Large Hadron Collider. The state is consistent with the ground isoscalar {{{{{{rm{T}}}}}}}_{{{{{{rm{c}}}}}}{{{{{rm{c}}}}}}}^{+} tetraquark with a quark content of {{{{{rm{c}}}}}}{{{{{rm{c}}}}}}overline{{{{{{rm{u}}}}}}}overline{{{{{{rm{d}}}}}}} and spin-parity quantum numbers JP = 1+. Study of the DD mass spectra disfavours interpretation of the resonance as the isovector state. The decay structure via intermediate off-shell D*+ mesons is consistent with the observed D0π+ mass distribution. To analyse the mass of the resonance and its coupling to the D*D system, a dedicated model is developed under the assumption of an isoscalar axial-vector {{{{{{rm{T}}}}}}}_{{{{{{rm{c}}}}}}{{{{{rm{c}}}}}}}^{+} state decaying to the D*D channel. Using this model, resonance parameters including the pole position, scattering length, effective range and compositeness are determined to reveal important information about the nature of the {{{{{{rm{T}}}}}}}_{{{{{{rm{c}}}}}}{{{{{rm{c}}}}}}}^{+} state. In addition, an unexpected dependence of the production rate on track multiplicity is observed.

Observation of an exotic narrow doubly charmed tetraquark

Conventional, hadronic matter consists of baryons and mesons made of three quarks and a quark–antiquark pair, respectively1,2. Here, we report the observation of a hadronic state containing four quarks in the Large Hadron Collider beauty experiment. This so-called tetraquark contains two charm quarks, a overline{{{{{u}}}}} and a overline{{{{{d}}}}} quark. This exotic state has a mass of approximately 3,875 MeV and manifests as a narrow peak in the mass spectrum of D0D0π+ mesons just below the D*+D0 mass threshold. The near-threshold mass together with the narrow width reveals the resonance nature of the state.

Susceptibility and field exposure of Striacosta albicosta (Lepidoptera: Noctuidae) eggs and larvae in Ontario, Canada to four insecticides.

Striacosta albicosta Smith (Lepidoptera: Noctuidae) is a primary pest of corn, Zea mays L., in the Great Lakes region, causing yield loss and exacerbating mycotoxin contamination of grain. Foliar insecticides are currently used to manage S.albicosta; however, the toxicity and residual activity of these insecticides against S.albicosta are unknown. Laboratory and field bioassays were conducted to determine the susceptibility and period of in-field efficacy provided by chlorantraniliprole, lambda-cyhalothrin, spinetoram, and methoxyfenozide against S.albicosta. Bioassay data were used to simulate management scenarios. For all insecticides tested, 1st instars were highly susceptible to the recommended field application rates and were >3-fold more susceptible to insecticides than 3rd instars. Insecticide activity decreased after application for all insecticides, with chlorantraniliprole having the longest residual activity. In simulated management scenarios where an insecticide was applied at or below the recommended 5% egg mass threshold with additional oviposition, methoxyfenozide application resulted in greater larval survival 14 days after application (DAA) than the other insecticides tested. In scenarios where insecticides were applied 7 days before threshold was reached, all insecticides resulted in larval survival. These data demonstrate that chlorantraniliprole, lambda-cyhalothrin and spinetoram, applied in conjunction with monitoring, provide effective control of S.albicosta larvae for 10-14 days, whereas methoxyfenozide provides effective control for less than 7 days. © 2022 Society of Chemical Industry.

Spectral walls at one loop

A spectral wall is a surface in a moduli space of classically BPS solitons where an internal excitation crosses the continuum mass threshold. It has recently been shown that spectral walls in classical field theory repel solitons whose corresponding internal excitations are excited. We investigate, for the first time, the fate of spectral walls in a quantum theory, calculating the instantaneous acceleration of a wave packet of classically BPS antikinks in the presence of an impurity. We find that, in the quantum theory, the antikinks are repelled even when the bound mode is not excited. Perhaps due to this repulsive force, the dramatic classical effects of the spectral wall are not seen in our quantum calculation.