758 research outputs found

    750 GeV Composite Axion as the LHC Diphoton Resonance

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    We propose that the 750 GeV resonance, presumably observed in the early LHC Run 2 data, could be a heavy composite axion that results from condensation of a hypothetical quark in a high-colour representation of conventional QCD. The model, motivated by a recently proposed solution to the strong CP problem, is very economical and is essentially defined by the properties of the additional quark - its colour charge, hypercharge and mass. The axion mass and its coupling to two photons (via axial anomaly) can be computed in terms of these parameters. The axion is predominantly produced via photon fusion (γγ→A\gamma\gamma \to {\cal A}) which is followed by Z Z vector boson fusion and associated production at the LHC. We find that the total diphoton cross section of the axion can be fitted with the observed excess. Combining the requirement on the cross-section, such that it reproduces the diphoton excess events, with the bounds on the total width (Γtot⩽45\Gamma_{tot} \leqslant 45 GeV), we obtain the effective coupling in the range 1.6×10−41.6\times 10^{-4} GeV−1≳CA≳6.5×10−5^{-1}\gtrsim C_{{\cal A}} \gtrsim 6.5\times 10^{-5} GeV−1^{-1}. Within this window of allowed couplings the model favours a narrow width resonance and yQ2∼O(10) y_{Q}^2 \sim \mathcal{O}(10). In addition, we observe that the associated production qqˉ→Aγ→γγγq\bar{q} \to {\cal A}\gamma\to \gamma\gamma\gamma can potentially produce a sizeable number of three photon events at future LHC and e+e− e^{+} e^{-} colliders. However, the rare decay Z→A∗γ→γγγZ\to\mathcal{A}^*\gamma \to \gamma\gamma\gamma is found to be too small to be probed at the LHC.Comment: 10 pages, 3 figures; Minor revision, updated references to be consistent with PLB published versio

    Exotic Lepton Searches via Bound State Production at the LHC

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    Heavy long-lived multi-charged leptons (MCLs) are predicted by various new physics models. These hypothetical MCLs can form bound states, due to their high electric charges and long life times. In this work, we propose a novel strategy of searching for MCLs through their bound state productions and decays. By utilizing LHC-8 TeV data in searching for resonances in the diphoton channel, we exclude the masses of isospin singlet heavy leptons with electric charge ∣q∣≥6|q|\geq 6 (in units of electron charge) lower than ∼\sim1.2 TeV, which are much stronger than the corresponding 8 TeV LHC bounds from analysing the high ionisation and the long time-of-flight of MCLs. By utilising the current 13 TeV LHC diphoton channel measurements the bound can further exclude MCL masses up to ∼\sim1.6 TeV for ∣q∣≥6|q|\geq 6. Also, we demonstrate that the conventional LHC limits from searching for MCLs produced via Drell-Yan processes can be enhanced by including the contribution of photon fusion processes.Comment: 9 pages, 3 figures, Updated to match PL

    A Comparison of Fluorescence and ETR Between Malosma laurina and Rhus integrifolia

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    Malosma laurina and Rhus integrifolia are both native species to the Santa Monica Mountains and belong to the same family, Anacardiaceae. The two natives have lived alongside each other but in recent years M. laurina has been heavily affected by the prolonged drought. The Malosma laurina population in the Santa Monica Mountains has withstood wildfires and droughts, and has remained relatively stable and healthy up until recently. A recent Pepperdine graduate published her findings explaining the high levels of dieback in Malosma laurina and attributed it to the fungus, B. dothidea. We hypothesized that Rhus integrifolia would have higher fluorescence and ETR rates because there have been no recorded cases of Rhus integrifolia being infected by the fungus or that it would physiologically outperform M. laurina. We concluded that there was no significant difference in light and dark adapted fluorescence rates between both plants. However, Malosma laurina proved to have a significanty higher electron transport rate

    Flow around submerged groynes in a sharp bend using a 3D LES model

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    River hydrodynamicsInteraction with structure

    Beliefs as Self-Sustaining Networks: Drawing Parallels Between Networks of Ecosystems and Adults’ Predictions

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    In this paper, we argue that beliefs share common properties with the self-sustaining networks of complex systems. Matching experiences are said to couple with each other into a mutually reinforcing network. The goal of the current paper is to spell out and develop these ideas, using our understanding of ecosystems as a guide. In Part 1 of the paper, we provide theoretical considerations relevant to this new conceptualization of beliefs, including the theoretical overlap between energy and meaning. In Part 2, we discuss the implications of this new conceptualization on our understanding of belief emergence and belief change. Finally, in Part 3, we provide an analytical mapping between beliefs and the self-sustaining networks of ecosystems, namely by applying to behavioral data a measure developed for ecosystem networks. Specifically, average accuracies were subjected to analyses of uncertainty (H) and average mutual information (AMI). The ratio between these two values yields degree of order, a measure of how organized the self-sustained network is. Degree of order was tracked over time and compared to the amount of explained variance returned by a categorical nonlinear principal components analysis (CATPCA). Finding high correspondence between the two measures of order, together with the theoretical groundwork discussed in Parts 1 and 2, lends preliminary validity to our theory that beliefs have important similarities to the structural characteristics of self-sustaining networks

    Study Effect of Gandaria Fruit Concentration on Seaweed (Eucheuma cottonii) Jelly Candy

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    The purpose of the research was to determine the chemical, physical and organoleptic characteristics of jelly candy with the addition of gandaria flesh. This study used a single randomized complete design with 5 treatment level and 2 replications. The treatment levels in this study were: P1 (Meat Gandaria), P2 (25% Meat Gandaria), P3 (50% Meat Gandaria), P4 (75% Meat Gandaria), P5 (100% Meat Gandaria). The results showed that the treatment using doubles flesh was better than the others because it had a water content (16,70%), ash content (0,92%), total sugar (23,71%), pH (5,25%), total acid (8,05%). The seaweed jelly candy turned out to be preferred by panelists in all categories of hedonic of taste (2,65%), aroma (2,35%), color (2,65%), texture (2,7%), general acceptance (2,9%), level of acidity (2,35%)

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=3−4\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.2≤8.2 \leq log(M⋆/M⊙)≤10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z≃3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (M⋆M_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AV−M⋆A_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AV−M⋆A_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M⋆/M⊙)≳9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M⋆/M⊙)≲9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA

    The VANDELS survey: Dust attenuation in star-forming galaxies at z=3−4\mathbf{z=3-4}

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    We present the results of a new study of dust attenuation at redshifts 3<z<43 < z < 4 based on a sample of 236236 star-forming galaxies from the VANDELS spectroscopic survey. Motivated by results from the First Billion Years (FiBY) simulation project, we argue that the intrinsic spectral energy distributions (SEDs) of star-forming galaxies at these redshifts have a self-similar shape across the mass range 8.2≤8.2 \leq log(M⋆/M⊙)≤10.6(M_{\star}/M_{\odot}) \leq 10.6 probed by our sample. Using FiBY data, we construct a set of intrinsic SED templates which incorporate both detailed star formation and chemical abundance histories, and a variety of stellar population synthesis (SPS) model assumptions. With this set of intrinsic SEDs, we present a novel approach for directly recovering the shape and normalization of the dust attenuation curve. We find, across all of the intrinsic templates considered, that the average attenuation curve for star-forming galaxies at z≃3.5z\simeq3.5 is similar in shape to the commonly-adopted Calzetti starburst law, with an average total-to-selective attenuation ratio of RV=4.18±0.29R_{V}=4.18\pm0.29. We show that the optical attenuation (AVA_V) versus stellar mass (M⋆M_{\star}) relation predicted using our method is consistent with recent ALMA observations of galaxies at 2<z<32<z<3 in the \emph{Hubble} \emph{Ultra} \emph{Deep} \emph{Field} (HUDF), as well as empirical AV−M⋆A_V - M_{\star} relations predicted by a Calzetti-like law. Our results, combined with other literature data, suggest that the AV−M⋆A_V - M_{\star} relation does not evolve over the redshift range 0<z<50<z<5, at least for galaxies with log(M⋆/M⊙)≳9.5(M_{\star}/M_{\odot}) \gtrsim 9.5. Finally, we present tentative evidence which suggests that the attenuation curve may become steeper at log(M⋆/M⊙)≲9.0(M_{\star}/M_{\odot}) \lesssim 9.0.Comment: 16 pages, 12 figures, accepted for publication in MNRA
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