bluuebunny/crossref_metadata_2025 huggingface dataset:
Enhanced NIR-I emission from water-dispersible NIR-II dye-sensitized core/active shell upconverting nanoparticles
Authors: Hazra Chanchal , Ullah Sajjad , Serge Correales York E. , Caetano Laís G. , Ribeiro Sidney J. L.
Published: March 2018

Water-dispersible NIR-II dye (IR-1061) sensitized core/active shell upconversion nanoparticles (800 nm emission of Tm3+ ion).
Yellow-emitting carbon-dots-impregnated carboxy methyl cellulose/poly-vinyl-alcohol and chitosan: stable, freestanding, enhanced-quenching Cu2+-ions sensor
Authors: Wu Qian , Wang Xiaojie , Rasaki Sefiu Abolaji , Thomas Tiju , Wang Chuanxi , Zhang Chi , Yang Minghui
Published: March 2018

Yellow-emitting carbon dots/polymer-based sensing films with good time stability and high quantum yields were used to sensitively and selectively detect Cu2+ ions due to strengthened aggregation-induced fluorescence quenching.
Colorectal polyp risk is linked to an elevated level of homocysteine
Authors: Sun Manchun , Sun Manyi , Zhang Li , Shi Songli
Published: March 2018

Several studies have reported an association between levels of folate, homocysteine, and vitamin B12 and the risk of colorectal polyps. Here, our aim is to examine the possible effect of folate, homocysteine, and vitamin B12 levels on the risk of colorectal polyps by means of meta-analysis based quantitative synthesis. According to our inclusion/exclusion criteria, a total of 13 case–control studies were enrolled. The P-value of the association test, standard mean difference (SMD), and 95% confidence interval (CI) were calculated. Pooled analysis data showed a negative correlation between the risk of colorectal polyps and the levels of serum folate, red blood cell (RBC) folate, or vitamin B12 (all P>0.05). Nevertheless, for homocysteine level, we also observed a statistically significant difference between cases and controls in the overall and subgroup analysis of hospital-based control (HB), population-based control (PB), Chinese, Caucasian, or Asian (all P<0.05, SMD > 0). We found that increased levels of homocysteine may be statistically and significantly related to the risk of colorectal polyps.
Promoting Conditional Use of Communication Skills for Learners With Complex Communication Needs: A Tutorial
Authors: Simacek Jessica , Reichle Joe , Byiers Breanne J. , Parker-McGowan Quannah , Dimian Adele F. , Elmquist Marianne
Published: March 2018

Purpose

Conditional use of communication skills refers to the ability of a learner to appropriately generalize and discriminate when, where, and how to communicate based on constant variation and shifts in environmental cues.

Method

We describe discrimination and generalization challenges encountered by learners with complex communication needs and ways in which these challenges are fostered through traditional communication intervention programming. We address arrangements in instruction that maximize the probability of learners acquiring the conditional use of new vocabulary and the modest instructional technology implemented when planning for generalization.

Results

We propose establishing well-discriminated and generalized use of new vocabulary items through the application of a general case instruction framework to communication intervention programming.

Conclusion

We provide intervention methodology, including intervention steps for general case instruction, a plethora of functional examples, and graphic displays to assess and intervene to promote conditional use of communication skills for learners with complex communication needs.
Unveiling the physical conditions of the youngest disks
Authors: van ’t Hoff Merel L. R. , Tobin John J. , Harsono Daniel , van Dishoeck Ewine F.
Published: March 2018

Context.Protoplanetary disks have been studied extensively, both physically and chemically, to understand the environment in which planets form. However, the first steps of planet formation are likely to occur already when the protostar and disk are still embedded in their natal envelope. The initial conditions for planet formation may thus be provided by these young embedded disks, of which the physical and chemical structure is poorly characterized.

Aims.We aim to constrain the midplane temperature structure, one of the critical unknowns, of the embedded disk around L1527. In particular, we set out to determine whether there is an extended cold outer region where CO is frozen out, as is the case for Class II disks. This will show whether young disks are indeed warmer than their more evolved counterparts, as is predicted by physical models.

Methods.We used archival ALMA data of13COJ= 2–1, C18OJ= 2–1 and N2D+J= 3–2 to directly observe the midplane of the near edge-on L1527 disk. The optically thick CO isotopologues allowed us to derive a radial temperature profile for the disk midplane, while N2D+, which can only be abundant when CO is frozen out, provides an additional constraint on the temperature. Moreover, the effect of CO freeze-out on the13CO, C18O and N2D+emission was investigated using 3D radiative transfer modeling.

Results.Optically thick13CO and C18O emission is observed throughout the disk and inner envelope, while N2D+is not detected. Both CO isotopologues have brightness temperatures ≳25 K along the midplane. Disk and envelope emission can be disentangled kinematically, because the largest velocities are reached in the disk. A power law radial temperature profile constructed using the highest midplane temperature at these velocities suggest that the temperature is above 20 K out to at least 75 au, and possibly throughout the entire 125 au disk. The radiative transfer models show that a model without CO freeze-out in the disk matches the C18O observations better than a model with the CO snowline at ~70 au. In addition, there is no evidence for a large (order of magnitude) depletion of CO.

Conclusions.The disk around L1527 is likely to be warm enough to have CO present in the gas phase throughout the disk, suggesting that young embedded disks can indeed be warmer than the more evolved Class II disks.
Galaxy and Mass Assembly (GAMA): The environmental dependence of the galaxy main sequence
Authors: Wang L. , Norberg P. , Brough S. , Brown M. J. I. , da Cunha E. , Davies L. J. , Driver S. P. , Holwerda B. W. , Hopkins A. M. , Lara-Lopez M. A. , Liske J. , Loveday J. , Grootes M. W. , Popescu C. C. , Wright A. H.
Published: March 2018

Aims: We aim to investigate if the environment (characterised by the host dark matter halo mass) plays any role in shaping the galaxy star formation main sequence (MS).

Methods: The Galaxy and Mass Assembly project (GAMA) combines a spectroscopic survey with photometric information in 21 bands from the far-ultraviolet (FUV) to the far-infrared (FIR). Stellar masses and dust-corrected star-formation rates (SFR) are derived from spectral energy distribution (SED) modelling using MAGPHYS. We use the GAMA galaxy group catalogue to examine the variation of the fraction of star-forming galaxies (SFG) and properties of the MS with respect to the environment.

Results: We examine the environmental dependence for stellar mass selected samples without preselecting star-forming galaxies and study any dependence on the host halo mass separately for centrals and satellites out to z ∼ 0.3. We find the SFR distribution at fixed stellar mass can be described by the combination of two Gaussians (referred to as the star-forming Gaussian and the quiescent Gaussian). Using the observed bimodality to define SFG, we investigate how the fraction of SFG F(SFG) and properties of the MS change with environment. For centrals, the position of the MS is similar to the field but with a larger scatter. No significant dependence on halo mass is observed. For satellites, the position of the MS is almost always lower (by ∼0.2 dex) compared to the field and the width is almost always larger. F(SFG) is similar between centrals (in different halo mass bins) and field galaxies. However, for satellites F(SFG) decreases with increasing halo mass and this dependence is stronger towards lower redshift.
Application of extrusion-cooking technique for foamed starch-based materials
Authors: Combrzyński Maciej , Mościcki Leszek , Mitrus Marcin , Kupryaniuk Karol , Oniszczuk Anna
Published: March 2018

Foamed materials are widely used, mainly as a protection objects during transport of various products. Traditionally foams are produced from plastics so they are very difficult for waste management. It is the challenge for many scientific centres to develop a technology for the production of bio-based materials which can be rapidly decomposed. The task for the researcher is to obtain a relatively cheap, easy to use and completely biodegradable materials. The aim of this work was the selection of the main raw materials, functional additives and process parameters to obtain the most effective parameters of extrusion-cooking process for foamed starch-based materials. Properties of the products and processing costs were taken into account. During the study, the extrusion-cooking process was performed under various conditions: temperature, humidity, type of the die, screw rotational speed, various raw materials and additives blends. The best results were obtained for mixtures based on potato starch and with addition the foaming agent Plastron foam PDE and poly(vinyl) alcohol PVA.
The effect of seed moisture and temperature on grinding characteristics of quinoa (Chenopodium quinoa Willd.)
Authors: Hassoon Waleed Hameed , Dziki Dariusz
Published: March 2018

Quinoa (Chenopodium quinoa Willd) is a native food plant of the Andean region of South America. Quinoa seeds have remarkable nutritional properties, not only from its high protein content, but also from its good amino acid balance. The aim of the study was evaluate the influence of quinoa seed moisture content (10, 12, 14, 16 and 18%) and temperature (-20, 3, 20 and 40°C, with the initial grain moisture content of 10.5%) on grinding process. Especially the particle size distributions and grinding energy indices were determined. The results showed that the increase of seed moisture content from 10 to 16% caused an increase the specific grinding energy from 6.9 to 8.3 kJ·kg-1, beside of this as the moisture increased the average particle also increased. The highest changes were observed in the fraction of coarse particles (above 1.0 mm). Interestingly, the mass fraction of fine particles (below 0.2 mm also increased). Other grinding indices also confirmed an increase the grinding energy requirements with the increase seed moisture content. The temperature of seed has little influence on quinoa grinding process. The highest grinding energy requirements were observed when the frozen seeds were ground.
Estimation methods of the agricultural equipment value with
regard toevaluation of Alina carrot harvester
Authors: Kowalczyk Zbigniew , Cupiał Michał
Published: March 2018

The objective of the paper is to present methods of evaluation of real estates used for evaluation of agricultural equipment and types of value related thereto. Alina carrot harvester by Waremczuk company served as an example, for which a detailed methodology and the results of valuation were presented.

Evaluation was carried out based on two approaches namely a comparative and cost approach. In the case of the comparative approach, the average price adjustment method was used and in the case of the cost approach - a replacement cost method.As a result of using various approaches and methods of evaluation two slightly different values of the evaluated harvester were obtained. It was respectively: EUR16,406 - at the use of the average price adjustment method and EUR 17,678 - the estimated net replacement value in the cost approach for the replacement method.
Content of Ni, Pb and Zn, in selected elements of ecosystem in three bays in the area of Sevastopol
Authors: Niemiec Marcin , Szeląg-Sikora Anna , Kuzminova Natalya , Komorowska Monika
Published: March 2018

The aim of the study was to evaluate the content of Ni, Pb and Zn in the water and larvae of fish of the genus Atherinidae L., caught in three bays in the area of Sevastopol. The study was conducted in 2012 in the three bays in the area of Sevastopol: Galubaya, Omega and Karantinna. The results indicate that the content of all elements studied was at a higher level than that observed in the uncontaminated basins. The average concentration of Ni, Pb and Zn in water was respectively: 1.199; 14.62 and 64.32 μg · dm-3. The content of the elements studied in the examined fish larvae Atherinidae ranged from 6.413 to 19.65 mg Ni kg -1, from 1.749 to 5.393 mg Pb kg -1 and from 97.16 to 215.24 mg Zn kg-1.
Influence of raw material properties on energy consumption during briquetting process
Authors: Ivanova Tatiana , Havrland Bohumil , Novotny Radek , Muntean Alexandru , Hutla Petr
Published: March 2018

Biomass is doubtless a very significant source of renewable energy being worldwide abundant with high energy potential. This paper deals with assessment energy consumption at especially grinding and briquetting processes, which should result in essential economy of energy at solid biofuel production. Various types of raw materials were used at the experiment such as hemp (Cannabis sativa L.) biomass, two species of Miscanthus (Miscanthus sinensis, Miscanthus x gigantheus) and apple wood biomass. These materials were dried, grinded and pressed by piston press having pressing chamber diameter of 65 mm. Materials were grinded into three fractions (4 mm, 8 mm and 12 mm). Material throughput (kg.h-1) and energy consumption (kWh.t-1) were registered. As to results: the highest throughput at both grinding cases as well as briquetting was found at apple wood biomass; however the energy consumption during briquetting of apple wood was relatively high. The worst results concerning throughput and energy consumption (especially at briquetting) were found at hemp biomass. Nevertheless, briquettes made of hemp had the best mechanical durability. Both Miscunthus species (herbaceous biomass) have very similar parameters and showed quite good relation between throughput and energy consumption at the used machines.
Characteristics of electricity quality parameters in agri-food processing plants
Authors: Necka Krzysztof , Trojanowska Małgorzata
Published: March 2018

The paper presents the results of electricity quality measurements conducted in six agri-food processing plants equipped with receivers of different sensitivity to the quality of the supply voltage. In particular, statistical assessment has been conducted for the value of the parameters characterizing the supply voltage, describing the parameters using the basic statistical measures and comparing them with the normative requirements. The paper also presents examples of the hazards to electrical drives and control systems caused by such industrial electromagnetic interferences as voltage changes or deformations of voltage waveform.
Impact of size and distribution of installed PV power in E-W direction on the level in which selected consumers’ energy needs were met
Authors: Necka Krzysztof , Latala Hubert , Kurpaska Sławomir , Knaga Jarosław , Karbowniczakʼ Anna
Published: March 2018

The aim of the study was to analyse the energy needs of selected consumers and to select the PV installed capacity in the east and west panels orientation (E-W). The analysis was carried out for two variants. The first concerned the impact of the installation power of a PV source on the contracted power in its symmetric east and west position. The second variant was the result of previous observations and studies of the authors of this paper. Thus, in this variant, the unbalanced power of PV E-W in relation to the S azimuth has been analyzed, taking into account the characteristics of the recipients' needs and the variation of the PV power installed. The analyses show that an increase in meeting the energy demand for two of the tested plants at symmetrical power distribution to the east and west occurred only when the installed power was increased to the level of approx. 1.4-1.6 of the contracted power. However, the power distribution in the E-W direction has a very strong effect on the energy amount that is generated in the power plant and cannot be used due to the lack of demand in the plant.
Influence of the Harvesting and Ensilage Technology on the Quality of Maize Straw Silage
Authors: Przybył Jacek , Wojcieszak Dawid , Kowalik Ireneusz , Dach Jacek
Published: March 2018

The aim of the study was to assess how the harvesting and ensilage technology influenced the quality of maize straw silages. The research findings showed that it was best to make maize straw silage in a flexible silo, whereas it was least favourable to make it in a film-covered field prism. The choice of the adequate ensilage method results in a high quality silage even if there is high content of dry matter in maize straw.
Influence of the composition and agglomeration pressure on the compaction level of the fertilizers based on biomass ash and digestate
Authors: Wróbel Marek , Frączek Jarosław , Mudryk Krzysztof , Jewiarz Marcin , Dziedzic Krzysztof
Published: March 2018

The paper presents the results of research aimed at determining the influence of the composition of the fertilizer mixtures and the compaction pressure on the specific density and density index of fertilizer granules. Investigated mixtures were prepared from fly ash from power plant fuelled by biomass and digestate from biogas plant. The urea, sulfur and phosphorite were also added as enhancing additives. For granule samples made on a strength machine, their specific density was determined on a quasifluid-pycnometer. To determine the effect of agglomerate pressure on the compaction process, the absolute density of the materials was omitted. In such case it was needed to introduce a density index AI. Such a presentation of the results obtained has made it possible to clearly determine how the density of the test mixture results in the applied agglomeration pressure. The specific density of the resulting granules was in the range of 0.85-1.27 g/cm3. The determined density index for the given pressure was in the following ranges: 0.44-0.49 g/cm3 (pressure 100MPa), 0.47-0.51 g/cm3 (pressure 150MPa) 0.51 - 0.59 g/cm3 (200MPa pressure). This means that, regardless of the contribution of components to the mixture at the given pressure, a similar degree of compaction was obtained.
Scientific and personal recollections of Roberto Petronzio
Authors: Parisi Giorgio
Published: March 2018

This paper aims to recall some of the main contributions of Roberto Petronzio to physics, with a particular regard to the period we have been working together. His seminal contributions cover an extremely wide range of topics: the foundation of the perturbative approach to QCD, various aspects of weak interaction theory, from basic questions (e.g. the mass of the Higgs) to lattice weak interaction, lattice QCD from the beginning to most recent computations.
Parton distributions in the LHC era
Authors: Del Debbio Luigi
Published: March 2018

Analyses of LHC (and other!) experiments require robust and statistically accurate determinations of the structure of the proton, encoded in the parton distribution functions (PDFs). The standard description of hadronic processes relies on factorization theorems, which allow a separation of process-dependent short-distance physics from the universal long-distance structure of the proton. Traditionally the PDFs are obtained from fits to experimental data. However, understanding the long-distance properties of hadrons is a nonperturbative problem, and lattice QCD can play a role in providing useful results from first principles. In this talk we compare the different approaches used to determine PDFs, and try to assess the impact of existing, and future, lattice calculations.
Axion dark matter and the Lattice
Authors: Moore Guy
Published: March 2018

First I will review the QCD theta problem and the Peccei-Quinn solution, with its new particle, the axion. I will review the possibility of the axion as dark matter. If PQ symmetry was restored at some point in the hot early Universe, it should be possible to make a definite prediction for the axion mass if it constitutes the Dark Matter. I will describe progress on one issue needed to make this prediction – the dynamics of axionic string-wall networks and how they produce axions. Then I will discuss the sensitivity of the calculation to the high temperature QCD topological susceptibility. My emphasis is on what temperature range is important, and what level of precision is needed.
Neutron Electric Dipole Moment on the Lattice
Authors: Yoon Boram , Bhattacharya Tanmoy , Gupta Rajan
Published: March 2018

For the neutron to have an electric dipole moment (EDM), the theory of nature must have T, or equivalently CP, violation. Neutron EDM is a very good probe of novel CP violation in beyond the standard model physics. To leverage the connection between measured neutron EDM and novel mechanism of CP violation, one requires the calculation of matrix elements for CP violating operators, for which lattice QCD provides a first principle method. In this paper, we review the status of recent lattice QCD calculations of the contributions of the QCD Θ-term, the quark EDM term, and the quark chromo-EDM term to the neutron EDM.
Looking behind the Standard Model with lattice gauge theory
Authors: Svetitsky Benjamin
Published: March 2018

Models for what may lie behind the Standard Model often require nonperturbative calculations in strongly coupled field theory. This creates opportunities for lattice methods, to obtain quantities of phenomenological interest as well as to address fundamental dynamical questions. I survey recent work in this area.
Lattice QCD on new chips: a community summary
Authors: Rago Antonio
Published: March 2018

I review the most recent evolutions of the QCD codes on new architectures, with a focus on the performances obtained by the different coding strategies as presented during the Lattice2017 conference.
A Numerical Study of Renormalization Group Transformations on Multiscale Lattices
Authors: Tu Jiqun , Mawhinney Robert
Published: March 2018

The RBC and UKQCD Collaborations have shown that light hadron masses and meson decay constants measured on 2+1 flavor Mobius DWF ensembles generated with the Iwasaki gauge action and a dislocation suppressing determinant ratio (DSDR) term show few percent O(a2) scaling violations for ensembles with a-1 = 1 GeV. We call this combination the ID+MDWF action and this scaling implies that, to a good approximation, these ensembles lie on a renormalization group trajectory, where the form of the action is unchanged and only the bare parameters need to be tuned to stay on the trajectory. Here we investigate whether a single-step APE-like blocking kernel can reproduce this trajectory and test its accuracy via measurements of the light hadron spectrum and non-perturbative renormalization. As we report, we find close matching to the renormalization group trajectory from this simple blocking kernel.
Fermion Bag Approach to Lattice Hamiltonian Field Theories
Authors: Huffman Emilie
Published: March 2018

Using a model in the Gross-Neveu Ising universality class, we show how the fermion bag idea can be applied to develop algorithms to Hamiltonian lattice field theories. We argue that fermion world lines suggest an alternative method to the traditional techniques for calculating ratios of determinants in a stable manner. We show the power behind these ideas by extracting the physics of the model on large lattices.
Background field Landau mode operators for the nucleon
Authors: Kamleh Waseem , Bignell Ryan , Leinweber Derek B. , Burkardt Matthias
Published: March 2018

The introduction of a uniform background magnetic field breaks threedimensional spatial symmetry for a charged particle and introduces Landau mode effects. Standard quark operators are inefficient at isolating the nucleon correlation function at nontrivial field strengths. We introduce novel quark operators constructed from the twodimensional Laplacian eigenmodes that describe a charged particle on a finite lattice. These eigenmode-projected quark operators provide enhanced precision for calculating nucleon energy shifts in a magnetic field. Preliminary results are obtained for the neutron and proton magnetic polarisabilities using these methods.
Charmonium resonances on the lattice
Authors: Bali Gunnar , Collins Sara , Mohler Daniel , Padmanath M. , Piemonte Stefano , Prelovsek Sasa , Weishäupl Simon
Published: March 2018

The nature of resonances and excited states near decay thresholds is encoded in scattering amplitudes, which can be extracted from single-particle and multiparticle correlators in finite volumes. Lattice calculations have only recently reached the precision required for a reliable study of such correlators. The distillation method represents a significant improvement insofar as it simplifies quark contractions and allows one to easily extend the operator basis used to construct interpolators. We present preliminary results on charmonium bound states and resonances on the Nf = 2+1 CLS ensembles. The long term goal of our investigation is to understand the properties of the X resonances that do not fit into conventional models of quark-antiquark mesons. We tune various parameters of the distillation method and the charm quark mass. As a first result, we present the masses of the ground and excited states in the 0++ and 1−− channels
ππ P-wave resonant scattering from lattice QCD
Authors: Paul Srijit , Alexandrou Constantia , Leskovec Luka , Meinel Stefan , Negele John W. , Petschlies Marcus , Pochinsky Andrew , Rendon Suzuki Jesus Gumaro , Syritsyn Sergey
Published: March 2018

We present a high-statistics analysis of the ρ resonance in ππ scattering, using 2 + 1 flavors of clover fermions at a pion mass of approximately 320 MeV and a lattice size of approximately 3:6 fm. The computation of the two-point functions are carried out using combinations of forward, sequential, and stochastic propagators. For the extraction of the ρ-resonance parameters, we compare different fit methods and demonstrate their consistency. For the ππ scattering phase shift, we consider different Breit-Wigner parametrizations and also investigate possible nonresonant contributions. We find that the minimal Breit-Wigner model is suffcient to describe our data, and obtain amρ = 0:4609(16)stat(14)sys and gρππ = 5:69(13)stat(16)sys. In our comparison with other lattice QCD results, we consider the dimensionless ratios amρ/amN and amπ/amN to avoid scale setting ambiguities.
Efficient operators for studying higher partial waves
Authors: Wu Jia-jun , Kamleh Waseem , Leinweber Derek B. , Schierholz Gerrit , Young Ross D. , Zanotti James M.
Published: March 2018

An extended multi-hadron operator is developed to extract the spectra of irreducible representations in the finite volume. The irreducible representations of the cubic group are projected using a coordinate-space operator. The correlation function of this operator is computationally effcient to extract lattice spectra. In particular, this new formulation only requires propagator inversions from two distinct locations, at fixed physical separation. We perform a proof-of-principle study on a 243 × 48 lattice volume with mπ ≈ 900 MeV by isolating the spectra of A+1, E+ and T+2 of the ππ system with isospin-2 in the rest frame.
Towards extracting the timelike pion form factor on CLS twoflavour ensembles
Authors: Erben Felix , Green Jeremy , Mohler Daniel , Wittig Hartmut
Published: March 2018

Results are presented from an ongoing study of the ρ resonance. The focus is on CLS 2-flavour ensembles generated using O(a) improved Wilson fermions with pion masses ranging from 265 to 437 MeV. The energy levels are extracted by solving the GEVP of correlator matrices, created with the distillation approach involving ρ and ππ interpolators. The study is done in the centre-of-mass frame and several moving frames. One aim of this work is to extract the timelike pion form factor after applying the Lüscher formalism. We therefore plan to integrate this study with the existing Mainz programme for the calculation of the hadronic vacuum polarization contribution to the muon g – 2.
η and η′ masses and decay constants
Authors: Bali Gunnar , Collins Sara , Simeth Jakob
Published: March 2018

We present preliminary results for the masses and decay constants of the η and η′ mesons using CLS Nf = 2 + 1 ensembles.

One of the major challenges in these calculations are the large statistical fluctuations due to disconnected quark loops. We tackle these by employing a combination of noise reduction techniques which are tuned to minimize the statistical error at a fixed cost. On the analysis side we carefully assess excited states contributions by using a direct fit
approach.
Baryon magnetic moments: Symmetries and relations
Authors: Parreño Assumpta , Savage Martin J. , Tiburzi Brian C. , Wilhelm Jonas , Chang Emmanuel , Detmold William , Orginos Kostas
Published: March 2018

Magnetic moments of the octet baryons are computed using lattice QCD in background magnetic fields, including the first treatment of the magnetically coupled ∑0- ⋀ system. Although the computations are performed for relatively large values of the up and down quark masses, we gain new insight into the symmetries and relations between magnetic moments by working at a three-flavor mass-symmetric point. While the spinflavor symmetry in the large Nc limit of QCD is shared by the naïve constituent quark model, we find instances where quark model predictions are considerably favored over those emerging in the large Nc limit. We suggest further calculations that would shed light on the curious patterns of baryon magnetic moments.
Pion mass dependence of the HVP contribution to muon g – 2
Authors: Golterman Maarten , Maltman Kim , Peris Santiago
Published: March 2018

One of the systematic errors in some of the current lattice computations of the HVP contribution to the muon anomalous magnetic moment g – 2 is that associated with the extrapolation to the physical pion mass. We investigate this extrapolation assuming lattice pion masses in the range of 220 to 440 MeV with the help of two-loop chiral perturbation theory, and find that such an extrapolation is unlikely to lead to control of this systematic error at the 1% level. This remains true even if various proposed tricks to improve the chiral extrapolation are taken into account.
ChPT loops for the lattice: pion mass and decay constant, HVP at finite volume and nn̅-oscillations
Authors: Bijnens Johan
Published: March 2018

I present higher loop order results for several calculations in Chiral perturbation Theory. 1) Two-loop results at finite volume for hadronic vacuum polarization. 2) A three-loop calculation of the pion mass and decay constant in two-flavour ChPT. For the pion mass all needed auxiliary parameters can be determined from lattice calculations of ππ-scattering. 3) Chiral corrections to neutron-anti-neutron oscillations.
Charmed states and flavour symmetry breaking
Authors: Horsley R. , Koumi Z. , Nakamura Y. , Perlt H. , Rakow P. E. L. , Schierholz G. , Schiller A. , Stüben H. , Young R. D. , Zanotti J. M.
Published: March 2018

Extending the SU(3) flavour symmetry breaking expansion from up, down and strange sea quark masses to partially quenched valence quark masses allows an extrapolation to the charm quark mass. This approach leads to a determination of charmed quark hadron masses and decay constants. We describe our recent progress and give preliminary results in particular with regard to the recently discovered doubly charmed baryon (the [see formula in PDF]) by the LHCb Collaboration.
Lattice study of finite volume effect in HVP for muon g-2
Authors: Izubuchi Taku , Kuramashi Yoshinobu , Lehner Christoph , Shintani Eigo
Published: March 2018

We study the finite volume effect of the hadronic vacuum polarization contribution to muon g-2, [see formula in PDF],in lattice QCD by comparison with two different volumes, L4 = (5.4)4 and (8.1)4 fm4, at physical pion. We perform the lattice computation of highly precise vector-vector current correlator with optimized AMA technique on Nf = 2 + 1 PACS gauge configurations in Wilson-clover fermion and stout smeared gluon action at one lattice cut-off, a−1 = 2.33 GeV. We compare two integrals of [see formula in PDF], momentum integral and time-slice summation, on the lattice and numerically show that the different size of finite volume effect appears between two methods. We also discuss the effect of backward-state propagation into the result of [see formula in PDF] with the different boundary condition. Our model-independent study suggest that the lattice computation at physical pion is important for correct estimate of finite volume and other lattice systematics in [see formula in PDF].
Progress in computing parton distribution functions from the quasi-PDF approach
Authors: Alexandrou Constantia , Cichy Krzysztof , Constantinou Martha , Hadjiyiannakou Kyriakos , Jansen Karl , Panagopoulos Haralambos , Scapellato Aurora , Steffens Fernanda
Published: March 2018

We discuss the current developments by the European Twisted Mass Collaboration in extracting parton distribution functions from the quasi-PDF approach. We concentrate on the non-perturbative renormalization prescription recently developed by us, using the RI′ scheme. We show results for the renormalization functions of matrix elements needed for the computation of quasi-PDFs, including the conversion to the MS scheme, and for renormalized matrix elements. We discuss the systematic effects present in the Z-factors and the possible ways of addressing them in the future.
Computing nucleon EDM on a lattice
Authors: Abramczyk Michael , Aoki Sinya , Blum Tom , Izubuchi Taku , Ohki Hiroshi , Syritsyn Sergey
Published: March 2018

I will discuss briefly recent changes in the methodology of computing the baryon EDM on a lattice. The associated correction substantially reduces presently existing lattice values for the proton and neutron theta-induced EDMs, so that even the most precise previous lattice results become consistent with zero. On one hand, this change removes previous disagreements between these lattice results and the phenomenological estimates of the nucleon EDM. On the other hand, the nucleon EDM becomes much harder to compute on a lattice. In addition, I will review the progress in computing quark chromo-EDM-induced nucleon EDM using chiral quark action.
Isovector and flavor-diagonal charges of the nucleon
Authors: Gupta Rajan , Bhattacharya Tanmoy , Jang Yong-Chull , Lin Huey-Wen , Yoon Boram
Published: March 2018

We present an update on the status of the calculations of isovector and flavor-diagonal charges of the nucleon. The calculations of the isovector charges are being done using ten 2+1+1-flavor HISQ ensembles generated by the MILC collaboration covering the range of lattice spacings a ≈ 0.12, 0.09, 0.06 fm and pion masses Mπ ≈ 310, 220, 130 MeV. Excited-states contamination is controlled by using four-state fits to two-point correlators and three-states fits to the three-point correlators. The calculations of the disconnected diagrams needed to estimate flavor-diagonal charges are being done on a subset of six ensembles using the stocastic method. Final results are obtained using a simultaneous fit in M2π, the lattice spacing a and the finite volume parameter MπL keeping only the leading order corrections.
Light-by-light forward scattering amplitudes in Lattice QCD
Authors: Gérardin Antoine , Green Jeremy , Gryniuk Oleksii , von Hippel Georg , Meyer Harvey B. , Pascalutsa Vladimir , Wittig Hartmut
Published: March 2018

We present our preliminary results on the calculation of hadronic light-by-light forward scattering amplitudes using vector four-point correlation functions computed on the lattice. Using a dispersive approach, forward scattering amplitudes can be described by γ*γ* → hadrons fusion cross sections and then compared with phenomenology. We show that only a few states are needed to reproduce our data. In particular, the sum rules considered in this study imply relations between meson–γγ couplings and provide valuable information about individual form factors which are often used to estimate the meson-pole contributions to the hadronic light-by-light contribution to the (g – 2) of the muon.
Improved real-time dynamics from imaginary frequency lattice simulations
Authors: Pawlowski Jan M. , Rothkopf Alexander
Published: March 2018

The computation of real-time properties, such as transport coefficients or bound state spectra of strongly interacting quantum fields in thermal equilibrium is a pressing matter. Since the sign problem prevents a direct evaluation of these quantities, lattice data needs to be analytically continued from the Euclidean domain of the simulation to Minkowski time, in general an ill-posed inverse problem. Here we report on a novel approach to improve the determination of real-time information in the form of spectral functions by setting up a simulation prescription in imaginary frequencies. By carefully distinguishing between initial conditions and quantum dynamics one obtains access to correlation functions also outside the conventional Matsubara frequencies. In particular the range between ω0 and ω1 = 2πT, which is most relevant for the inverse problem may be more highly resolved. In combination with the fact that in imaginary frequencies the kernel of the inverse problem is not an exponential but only a rational function we observe significant improvements in the reconstruction of spectral functions, demonstrated in a simple 0+1 dimensional scalar field theory toy model.
Dispersion relations of charmonia above Tc
Authors: Kitazawa Masakiyo , Ikeda Atsuro , Asakawa Masayuki
Published: March 2018

We study spectral properties of charmonia in the vector and pseudoscalar channels at nonzero momenta on quenched lattices focusing on the dispersion relation and the weight of the peak. The spectral functions of charmonia are studied by the maximum entropy method with the lattice Euclidean correlation functions on the anisotropic quenched lattices. The errors of the dispersion relations and the residues of the peak are analysed in the maximum entropy method. We find a significant increase of the masses of charmonia in medium. We also find that the functional form of the dispersion relations is not changed from that in the vacuum within the error even at T = 1:6Tc.

Preprint number: J-PARC-TH-0111
New techniques and results for worldline simulations of lattice field theories
Authors: Giuliani Mario , Orasch Oliver , Gattringer Christof
Published: March 2018

We use the complex ø4 field at finite density as a model system for developing further techniques based on worldline formulations of lattice field theories. More specifically we: 1) Discuss new variants of the worm algorithm for updating the ø4 theory and related systems with site weights. 2) Explore the possibility of canonical simulations in the worldline formulation. 3) Study the connection of 2-particle condensation at low temperature to scattering parameters of the theory.
Gluon and ghost correlation functions of 2-color QCD at finite density
Authors: Hajizadeh Ouraman , Boz Tamer , Maas Axel , Skullerud Jon-Ivar
Published: March 2018

2-color QCD, i. e. QCD with the gauge group SU(2), is the simplest non-Abelian gauge theory without sign problem at finite quark density. Therefore its study on the lattice is a benchmark for other non-perturbative approaches at finite density. To provide such benchmarks we determine the minimal-Landau-gauge 2-point and 3-gluon correlation functions of the gauge sector and the running gauge coupling at finite density. We observe no significant effects, except for some low-momentum screening of the gluons at and above the supposed high-density phase transition.
Simulating lattice field theories on multiple thimbles
Authors: Renzo Francesco Di
Published: March 2018

Simulating thimble regularization of lattice field theory can be tricky when more than one thimble is to be taken into account. A couple of years ago we proposed a solution for this problem. More recently this solution proved to be effective in the case of 0+1 dimensional QCD. A few lessons we can learnt, including the role of symmetries and general hints on algorithmic solutions.
Equation of state in (2+1)-flavor QCD at physical point with improved Wilson fermion action using gradient flow
Authors: Kanaya Kazuyuki , Ejiri Shinji , Iwami Ryo , Kitazawa Masakiyo , Suzuki Hiroshi , Taniguchi Yusuke , Umeda Takashi
Published: March 2018

We study the energy-momentum tensor and the equation of state as well as the chiral condensate in (2+1)-flavor QCD at the physical point applying the method of Makino and Suzuki based on the gradient flow. We adopt a nonperturbatively O(a)- improved Wilson quark action and the renormalization group-improved Iwasaki gauge action. At Lattice 2016, we have presented our preliminary results of our study in (2+1)- flavor QCD at a heavy u; d quark mass point. We now extend the study to the physical point and perform finite-temperature simulations in the range T ≃ 155.544 MeV (Nt = 4-14 including odd Nt’s) at a ≃ 0:09 fm. We show our final results of the heavy QCD study and present some preliminary results obtained at the physical point so far.
Restoring canonical partition functions from imaginary chemical potential
Authors: Bornyakov V.G. , Boyda D. , Goy V. , Molochkov A. , Nakamura A. , Nikolaev A. , Zakharov V.I.
Published: March 2018

Using GPGPU techniques and multi-precision calculation we developed the code to study QCD phase transition line in the canonical approach. The canonical approach is a powerful tool to investigate sign problem in Lattice QCD. The central part of the canonical approach is the fugacity expansion of the grand canonical partition functions. Canonical partition functions Zn(T) are coefficients of this expansion. Using various methods we study properties of Zn(T). At the last step we perform cubic spline for temperature dependence of Zn(T) at fixed n and compute baryon number susceptibility χB/T2 as function of temperature. After that we compute numerically ∂χ/∂T and restore crossover line in QCD phase diagram. We use improved Wilson fermions and Iwasaki gauge action on the 163 × 4 lattice with mπ/mρ = 0.8 as a sandbox to check the canonical approach. In this framework we obtain coefficient in parametrization of crossover line Tc(µ2B) = Tc(C−ĸµ2B/T2c) with ĸ = −0.0453 ± 0.0099.
The equation of state with non-equilibrium methods
Authors: Nada Alessandro , Caselle Michele , Panero Marco
Published: March 2018

Jarzynski’s equality provides an elegant and powerful tool to directly compute differences in free energy in Monte Carlo simulations and it can be readily extended to lattice gauge theories to compute a large set of physically interesting observables. In this talk we present a novel technique to determine the thermodynamics of stronglyinteracting matter based on this relation, which allows for a direct and efficient determination of the pressure using out-of-equilibrium Monte Carlo simulations on the lattice. We present results for the equation of state of the SU(3) Yang-Mills theory in the confined and deconfined phases. Finally, we briefly discuss the generalization of this method for theories with fermions, with particular focus on the equation of state of QCD.
Updates on the Columbia plot and its extended/alternative versions
Authors: Cuteri Francesca , Czaban Christopher , Philipsen Owe , Sciarra Alessandro
Published: March 2018

We report on the status of ongoing investigations aiming at locating the deconfinement critical point with standard Wilson fermions and Nf = 2 flavors towards the continuum limit (standard Columbia plot); locating the tricritical masses at imaginary chemical potential with unimproved staggered fermions at Nf = 2 (extended Columbia plot); identifying the order of the chiral phase transition at μ = 0 for Nf = 2 via extrapolation from non integer Nf (alternative Columbia plot).
Fluctuations of conserved charges from imaginary chemical potential
Authors: Guenther Jana N. , Borsányi Szabolcs , Fodor Zoltan , Katz Sandor D. , Pásztor Attila , Ratti Claudia
Published: March 2018

When comparing lattice calculation to experimental data from heavy ion collision experiments, the higher order fluctuations of conserved charges are important observables. An efficient way to study these fluctuations is to determine them from simulations at imaginary chemical potential. In this talk we present results up to the six order derivative in μB (with up to eighth order included in the fit), calculated on a 483 × 12 lattice with staggered fermions using different values of μB while μS = μQ = 0.
The pion quasiparticle in the low-temperature phase of QCD
Authors: Brandt Bastian B. , Francis Anthony , Meyer Harvey B. , Robaina Daniel , Zapp Kai
Published: March 2018

We extend our previous studies [PhysRevD.90.054509, PhysRevD.92.094510] of the pion quasiparticle in the low-temperature phase of two-flavor QCD with support from chiral effective theory. This includes the analysis performed on a finite temperature ensemble of size 20 × 643 at T ≈ 151MeV and a lighter zero-temperature pion mass mπ ≈ 185 MeV. Furthermore, we investigate the Gell-Mann–Oakes-Renner relation at finite temperature and the Dey-Eletsky-Ioffe mixing theorem at finite quark mass.
Real-time dynamics of matrix quantum mechanics beyond the classical approximation
Authors: Buividovich Pavel , Hanada Masanori , Schäfer Andreas
Published: March 2018

We describe a numerical method which allows to go beyond the classical approximation for the real-time dynamics of many-body systems by approximating the many-body Wigner function by the most general Gaussian function with time-dependent mean and dispersion. On a simple example of a classically chaotic system with two degrees of freedom we demonstrate that this Gaussian state approximation is accurate for significantly smaller field strengths and longer times than the classical one. Applying this approximation to matrix quantum mechanics, we demonstrate that the quantum Lyapunov exponents are in general smaller than their classical counterparts, and even seem to vanish below some temperature. This behavior resembles the finite-temperature phase transition which was found for this system in Monte-Carlo simulations, and ensures that the system does not violate the Maldacena-Shenker-Stanford bound λL < 2πT, which inevitably happens for classical dynamics at sufficiently small temperatures.
Testing a non-perturbative mechanism for elementary fermion mass generation: lattice setup
Authors: Capitani Stefano , Divitiis Giulia Maria de , Dimopoulos Petros , Frezzotti Roberto , Garofalo Marco , Knippschild Bastian , Kostrzewa Bartosz , Pittler Ferenc , Rossi Giancarlo , Urbach Carsten
Published: March 2018

In this contribution we lay down a lattice setup that allows for the nonperturbative study of a field theoretical model where a SU(2) fermion doublet, subjected to non-Abelian gauge interactions, is also coupled to a complex scalar field doublet via a Yukawa and an “irrelevant” Wilson-like term. Using naive fermions in quenched approximation and based on the renormalizedWard identities induced by purely fermionic chiral transformations, lattice observables are discussed that enable: a) in theWigner phase, the determinations of the critical Yukawa coupling value where the purely fermionic chiral transformation become a symmetry up to lattice artifacts; b) in the Nambu-Goldstone phase of the resulting critical theory, a stringent test of the actual generation of a fermion mass term of non-perturbative origin. A soft twisted fermion mass term is introduced to circumvent the problem of exceptional configurations, and observables are then calculated in the limit of vanishing twisted mass.