Fragmentation Contribution Research Articles

Application of the EBSD Technique in the Study of Porosity and Permeability in Deformation Bands in Sandstone.

Deformation bands are common constituents of porous clastic fluid reservoirs. Various techniques have been used to study deformation band structure and the associated changes in porosity and permeability. However, the use of electron backscatter diffraction technique is limited. Thus, more information is needed regarding the crystallographic relationships between detrital crystals, which can significantly impact reservoir rock quality. We employ microscopic and microstructural investigation techniques to analyze the influence of cataclastic deformation bands on pore space. Porosity measurements of the Cretaceous Ilhas Group sandstone in NE Brazil, obtained through computerized microtomography, indicate that the undeformed domains exhibit a total porosity of up to 13%. In contrast, this porosity is slightly over 1% in the deformation bands. Scanning electron microscopy analyses revealed the presence of grain fragmentation and dissolution microstructures, along with cement-filling pre-existing pores. The electron backscatter diffraction analyses indicated extensive grain fragmentation and minimal contribution from intracrystalline plasticity as a deformation mechanism. However, the c axes of quartz crystals roughly align parallel to the orientation of the deformation band. In summary, we have confirmed and quantified the internal changes in a deformation band cluster, with grain size reduction and associated compaction as the main mechanism supported by quartz cementation.

Exclusive production of double light neutral mesons at the e+e− colliders

In this work we investigate the exclusive production of a pair of light neutral mesons in e+e− annihilation, where the final state bears an even C-parity. The production processes can be initiated via the photon fragmentation or the nonfragmentation mechanism. While the fragmentation contribution can be rigorously accounted, the nonfragmentation contributions are calculated within the framework of collinear factorization, where only the leading-twist light-cone distribution amplitudes (LCDAs) of mesons are considered. Mediately solely by the nonfragmentation mechanism, the production rates of double light neutral pseudoscalar mesons are too small to be observed at the commissioning e+e− facilities. In contrast, the production rates of a pair of light neutral vector mesons are greatly amplified owing to the significant kinematic enhancement brought by the fragmentation mechanism. It is found that, at s=3.77 GeV, after including the destructive interference between the nonfragmentation and fragmentation contributions, the production rates for e+e−→ρ0ρ0 and ρ0ω can be lowered by about 10% and 30% relative to the fragmentation predictions. Future precise measurement of these exclusive double neutral vector meson production channels at BESIII experiment may provide useful constraints on the LCDAs of light vector mesons. Published by the American Physical Society 2024

Polarized TMD fragmentation functions for J/ψ production

We calculate the matching, at leading order, of the transverse momentum-dependent fragmentation functions (TMDFFs) for light quarks and gluons fragmenting to a J/ψ onto polarized nonrelativistic QCD (NRQCD) TMDFFs. The NRQCD TMDFFs have an operator product expansion in terms of nonperturbative NRQCD production matrix elements. Using the results we obtain, we make predictions for the light quark fragmentation contribution to the production of polarized J/ψ in semi-inclusive deep inelastic scattering (SIDIS) both for unpolarized and longitudinally polarized beams. These results are an important contribution to polarized J/ψ production in SIDIS and thus are needed for comparison with experiments at the future Electron-Ion Collider. Published by the American Physical Society 2024

Exploring the spin structure of the nucleon at STAR

Understanding the internal spin structure of the nucleon remains a challenge in strong interaction physics. The unique capability of RHIC opened new avenues in studying the internal structure of the proton with unprecedented depth and precision. Significant progress has been made in the last few years through various measurements at STAR. The longitudinal spin measurements have contributed significantly to our understanding of the quark and gluon helicity distributions inside the proton. The longitudinal double-spin asymmetry, ALL, from STAR inclusive jet and dijet measurements provides the first evidence of a positive gluon polarization with partonic momentum fraction x > 0.05. The reconstruction of W±/Z in longitudinally polarized proton-proton collisions indicates that there is a flavor separation of the light sea quark helicity distributions. In transversely polarized proton collisions, W±/Z-bosons provide the first constraint on the sea-quark Sivers function and contributes to the tests of the predicted sign change. The tilt of the dijet opening angle provides a direct access to the first Mellin momentum of the Sivers function and avoids the spin-correlated fragmentation contributions. The novel measurements of the azimuthal distributions of identified hadrons in jets and spin-dependent dihadron correlations directly probe the collinear quark transversity in the proton, with the former coupled to the transverse momentum dependent (TMD) Collins fragmentation function and the latter to the dihadron interference fragmentation function. These measurements shed lights on Sivers function, quark transversity and spin-dependent fragmentation functions in both collinear and TMD formalism. In this proceeding, recent jet results on both the longitudinal and transverse spin structure of the proton from STAR are presented.

New derivation of the twist-3 gluon fragmentation contribution to polarized hyperon production

A novel method of formulating the twist-3 gluon fragmentation function contribution to hyperon polarization in the proton-proton collision is presented. The method employs a covariant gauge and takes full advantage of the Ward-Takahashi identities before performing the collinear expansion. It provides a robust way of constructing the general cross section formula and also a clear understanding for the absence of the ghostlike terms in the twist-3 cross section in the leading order with respect to the QCD coupling constant.

Role of initial gluon emission in double J/ψ production at central rapidities

We consider the process of double $J/\ensuremath{\psi}$ production in $pp$ collisions at the LHC in the framework of the ${k}_{T}$-factorization approach. We focus on the gluon fragmentation mechanism which is related to multiple gluon emission in the initial state. The initial state emission is treated according to Catani-Ciafaloni-Fiorani-Marchesini evolution equation, and applies to both single and double parton scattering cases. We show the importance of fragmentation contributions to $J/\ensuremath{\psi}$ pair production and perform a comparison between theoretical predictions and the latest ATLAS data collected at $\sqrt{s}=8\text{ }\text{ }\mathrm{TeV}$. We find that the effects of multiple gluon emission are essential for both single- and multiparton interaction processes. Finally, we highlight the problem of correct choice of the factorization scale with respect to numerical stability of the calculations and the consistency with noncollinear evolution equations.

Longitudinal double helicity asymmetry $A_{LL}$ from direct photon, jet and charged pion production in polarized $\vec{p}+\vec{p}$ collisions

Understanding the proton spin composition from the quarks and gluons spin polarization and their motion is important to test various kinds of sum rules and nonperturbative properties of hadrons. At the Relativistic Heavy Ion Collider (RHIC), we collide longitudinally polarized proton beams and measure the double helicity asymmetry A_{LL}ALL, which is an important physical quantity for extracting the polarized parton distribution functions (PDFs) of the proton. Direct photon, jet and charged pion production are good channels to probe the gluon spin polarization inside the proton, with the ability to probe also the sign of the gluon spin. Direct photon production is the theoretically ``cleanest’’ channel, with little fragmentation contribution, but limited by statistics. On the other hand, jet and charged pion production have more statistics, but include more hard processes and hadronization effects. I will present the recent measurements of direct photon, jet and charged pion A_{LL}ALLs at PHENIX and show their complementary roles in extracting the gluon spin.

NNLO photon fragmentation within antenna subtraction

We report on our recent progress towards including the photon fragmentation contribution in next-to-next-to-leading order (NNLO) QCD predictions for photon production cross sections. This extension to previous NNLO calculations requires the identification of the photon in singular parton-photon collinear limits. We discuss how these limits can be subtracted within antenna subtraction using fragmentation antenna functions and we outline their integration.

Energy-based fragmentation contribution approach for calculating the fluorescence spectrum of biomacromolecules

It remains challenging to calculate the fluorescence spectra of biomacromolecules due to the large number of atoms involved. Here, we propose an efficient computation method, named the energy-based fragmentation contribution (EBFC) approach, to calculate the fluorescence spectra of super-large proteins. Specifically, an optimized molecular tailoring rule is provided to divide a super-large protein into smaller fragments, then the extended tight binding method and the simplified time-dependent density functional theory approach are employed to calculate the fluorescence spectrum of each fragment in parallel, and finally, the fluorescence spectrum of the target protein is obtained by superimposing the contributions of all fragments. Utilizing the EBFC approach, we calculated fluorescence spectra of three different super-large proteins and the calculated spectra show excellent agreement with experimental data with the difference of less than 1.5%. This work provides an efficient and reliable approach to enhance the modeling capability of the excited states in biomacromolecules.

Corrigendum

Cereal ChemistryVolume 98, Issue 4 p. 994-994 CORRIGENDUMFree Access Corrigendum This article corrects the following: Damaged starch in pea versus wheat flours: Fragmentation behavior and contribution of fine and coarse fractions Anne-Flore Monnet, Alexandre Eurieult, Sophie Berland, Giana Almeida, Marie-Hélène Jeuffroy, Camille Michon, Volume 96Issue 3Cereal Chemistry pages: 465-477 First Published online: April 5, 2019 First published: 09 July 2021 https://doi.org/10.1002/cche.10461AboutSectionsPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat In Monnet et al., 2019, the formulas on pages 468 and 469 were published incorrectly. The formula on page 468 is incorrectly stated as (1) The correct formula should read: (1) The formula on page 469 is incorrectly stated as (2) The correct formula should read: (2) REFERENCE Monnet, A.-F., Eurieult, A., Berland, S., Almeida, G., Jeuffroy, M.-H., & Michon, C. (2019). Damaged starch in pea versus wheat flours: Fragmentation behavior and contribution of fine and coarse fractions. Cereal Chemistry, 96, 465– 477. https://doi.org/10.1002/cche.10146Wiley Online LibraryCASWeb of Science®Google Scholar Volume98, Issue4July/August 2021Pages 994-994 ReferencesRelatedInformation

Particle therapy and radioprotection in space with the FOOT experiment

The evaluation of nuclear fragmentation contribution on the delivered dose during particle therapy treatment is still an open point. The FOOT (FragmentatiOn Of Target) experiment aims to improve the actual knowledge of nuclear physics by measuring the differential cross section as a function of the energy and angle of the fragments produced when an external particle beam interacts with patent tissues during hadrontherapy treatment. Depending on the beam energy, the purpose of the measurements is dual: in the range of 150–400 MeV/u, they will be used to evaluate the side effects of the nuclear fragmentation in the hadrontherapy treatment, while in the range of 700–1000 MeV/u (typical of cosmic galactic rays) they will be used to optimize the shielding of the spaceship for long term space missions. The FOOT detector includes a pre-target region with a first plastic scintillator for time of flight (TOF) and trigger purpose, and a beam monitor drift chamber to evaluate the beam direction (necessary for the inverse kinematic approach); a magnetic spectrometer to measure the momentum of fragments; and finally a second plastic scintillator for deposited energy (ΔE) and TOF measurements, and a scintillating crystal calorimeter to measure the kinetic energy of fragments. These measurements will be combined to accurately identify the charge and mass of fragments. The experiment, funded by the INFN since September 2017, is in the construction phase. It has performed several test beams, while the full detector data taking is scheduled in the next few years. A full description of the different setups together with the performances obtained with the latest geometry studies are reported here.

From [formula omitted] production asymmetry at the LHC to prompt ντ at IceCube

The description of the heavy meson production at large energies and forward rapidities at the LHC is fundamental to derive realistic predictions of the prompt atmospheric neutrino flux at the IceCube Observatory. In particular, the prompt tau neutrino flux is determined by the decay of Ds mesons produced in cosmic ray–air interactions at high energies and large values of the Feynman-xF variable. Recent data of the LHCb Collaboration indicate a production asymmetry for Ds+ and Ds− mesons, which cannot be explained in terms of the standard modeling of the hadronization process. In this paper we demonstrate that this asymmetry can be described assuming an asymmetric strange sea (s(x)≠s¯(x)) in the proton wave function and taking into account the dominant charm and subdominant strange fragmentation into Ds mesons. Moreover, we show that the strange quark fragmentation contribution is dominant at large-xF (≥0.3). The prompt ντ flux is calculated and the enhancement associated with the strange quark fragmentation contribution, disregarded in previous calculations, is estimated. The considered scenario leads to quite sizable enhancement of the high-energy τ-neutrino flux.

Formula omitted] production in Pb–Pb collisions at [formula omitted] TeV

A measurement of the production of prompt Λc+ baryons in Pb–Pb collisions at sNN=5.02 TeV with the ALICE detector at the LHC is reported. The Λc+ and Λ‾c− were reconstructed at midrapidity (|y|<0.5) via the hadronic decay channel Λc+→pKS0 (and charge conjugate) in the transverse momentum and centrality intervals 6<pT<12 GeV/c and 0–80%. The Λc+/D0 ratio, which is sensitive to the charm quark hadronisation mechanisms in the medium, is measured and found to be larger than the ratio measured in minimum-bias pp collisions at s=7 TeV and in p–Pb collisions at sNN=5.02 TeV. In particular, the values in p–Pb and Pb–Pb collisions differ by about two standard deviations of the combined statistical and systematic uncertainties in the common pT interval covered by the measurements in the two collision systems. The Λc+/D0 ratio is also compared with model calculations including different implementations of charm quark hadronisation. The measured ratio is reproduced by models implementing a pure coalescence scenario, while adding a fragmentation contribution leads to an underestimation. The Λc+ nuclear modification factor, RAA, is also presented. The measured values of the RAA of Λc+, Ds+ and non-strange D mesons are compatible within the combined statistical and systematic uncertainties. They show, however, a hint of a hierarchy (RAAD0<RAADs+<RAAΛc+), conceivable with a contribution from coalescence mechanisms to charm hadron formation in the medium.

Damaged starch in pea versus wheat flours: Fragmentation behavior and contribution of fine and coarse fractions

AbstractBackground and objectivesParticle size distribution and damaged starch content have a major impact on flour quality because they influence the behavior of flour during hydration in processing. Particle size distribution and starch damage of legume flours and their relationship during grinding have not been evaluated. The standard enzymatic method for the measurement of damaged starch content (AACC 76‐31) was used to find a new calibration equation for the rapid amperometric method (SDmatic, AACC 76‐33.01) for legume flours. Changes in particle size distribution and starch damage during regrinding in a commercial pea flour were compared with those in a commercial wheat flour.FindingsLegume flours had a smaller damaged starch content (0.8–4.7 SD%) than wheat flours (2.2–7.0 SD%). The bimodal particle size distribution of flours was linked to structural elements as confirmed by environmental scanning electron microscopy and laser granulometry. Particle size distribution and starch damage varied concomitantly during regrinding in the commercial pea flour as in the commercial wheat flour. The main factor responsible for the increase in damaged starch content was an increase in the proportion of the fine fraction in the flour. Fine fractions contained higher damaged starch contents than coarse fractions.ConclusionsHypotheses concerning differences in fragmentation mechanisms in the two flours were formulated, suggesting that pea flour has a higher likelihood for fracture but less tendency to produce damaged starch than wheat flour.Significance and noveltyThe amperometric method (AACC 76‐33.01) can be used for a rapid estimation of the damaged starch content in legume flours. Furthermore, the results suggest a lower hardness of pea flour material compared to wheat flour material that would have a significant impact on milling strategies.

Single spin asymmetries in ultraperipheral p↑A collisions

We suggest inclusive hadron production in ultra-peripheral proton-nucleus collisions (UPCs) $p^\uparrow A \to h AX$ as a new channel to investigate single spin asymmetries (SSAs), in particular, to test the assumed dominance of the contribution from twist-three fragmentation functions. The UPC cross sections are obtained by considering the photoproduction limit of semi-inclusive deep inelastic scattering (SIDIS). In particular, we find simple formulas for the polarized UPC cross sections in the collinear twist-three framework. We then numerically calculate the fragmentation contribution to SSA in $p^\uparrow A \to \pi A X$ at $\sqrt{s} = 200$ GeV and find a few percent asymmetry in the forward region.

A coupled DEM-CFD analysis of asphaltene particles agglomeration and fragmentation

In the present paper, a Discrete Element Method-Computational Fluid Dynamics (DEM-CFD) approach along with a new coalescence model is adopted to study agglomeration and fragmentation of asphaltene particles, thoroughly. The collisions of asphaltene particles are investigated in three categories: collisions between individual primary particles (P-P collisions), individual primary particles and flocs (P-F collisions) and between flocs (F-F collisions). In addition, corresponding collision efficiencies have been determined based on the proposed coalescence model. Moreover, the importance of three different fragmentation modes including binary flocs fragmentations (binary fragmentation), detachment of a primary particle from floc (erosion) and splitting of floc into smaller flocs (large-scale fragmentation) is comparatively assessed. Eventually, the effect of fluid velocity and primary particles concentration on the aforementioned processes as well as asphaltene flocs properties are examined. Simulation results reveal P-P collisions contribution decreases continuously to reach a plateau in steady state condition while the contribution of P-F collisions increases initially and then it shows a gentle downward trend. F-F collisions contribution grows constantly up to steady state condition. The P-P and P-F collision efficiencies approximately remain constant whereas F-F collision efficiency continuously increases. In terms of fragmentation modes, contributions of binary fragmentation and erosion gradually decrease while large-scale fragmentation contribution constantly increases before steady state condition.

Comments on “Study of J/ψ production in jets”

Recent LHCb measurements of the [Formula: see text] meson production in jets are analyzed using fragmentation jet function formalism. It is shown that disagreement with theoretical predictions for distribution over the fraction of [Formula: see text] transverse momentum [Formula: see text] in the cases of prompt production can be explained if one takes into account evolution of the fragmentation function and contributions from double parton scattering (DPS) mechanism or gluon fragmentation.

Single spin asymmetries in forward p−p/A collisions revisited: The role of color entanglement

We calculate the single transverse spin asymmetries(SSA) for forward inclusive particle production in pp and pA collisions using a hybrid approach. It is shown that the Sivers type contribution to the SSA drops out due to color entanglement effect, whereas the fragmentation contribution to the spin asymmetry is not affected by color entanglement effect. This finding offers a natural solution for the sign mismatch problem.

Twist-3 fragmentation contribution to polarized hyperon production in unpolarized hadronic collisions

It has been known for a long time that hyperons produced in hadronic collisions are polarized perpendicular to the production plane of the reaction. This effect cannot be described by using twist-2 collinear parton correlators only. Here we compute the contribution of twist-3 fragmentation functions to the production of transversely polarized hyperons in unpolarized proton-proton collisions in the framework of collinear factorization. By taking into account the relations among the relevant twist-3 fragmentation functions which follow from the QCD equation of motion and the Lorentz invariance property of the correlators, we present the leading-order cross section for this term.

Diquark Fragmentation Contribution in Λ b Production

In the framework of the quark-diquark model of baryons, Λ b can be considered as b constituent quark an ud constituent diquark. In this study, we investigate the effect ud scalar diquark fragmentation into Λ b , therefor we calculate frgmentation functions of b quark and ud diquark into Λ b baryon through the use of perturbative QCD. In the next stage, throuth the use of the obtained fragmentation functions, we calculate the total fragmentation probabilities and average fragmentation parameters for b→Λ b and u d→Λ b . Finally, the inclusive cross section of Λ b baryon in electron-positron annihilation in ALEPH experiment is calculated with regard to ud diquark fragmentation contribution.