2,409 research outputs found
Investigating the spectroscopy behavior of undetected -wave charmed baryons
In this work, we investigate the spectroscopic properties of -wave
charmed baryons, which have not yet been observed in experiments. We employ a
non-relativistic potential model and utilize the Gaussian expansion method to
obtain the mass spectra of these charmed baryons. Additionally, we focus on the
two-body Okubo-Zweig-Iizuka allowed strong decay behaviors, which plays a
crucial role in characterizing the properties of these baryons. Our
comprehensive analyses of the mass spectra and two-body Okubo-Zweig-Iizuka
allowed decay behaviors provides valuable insights for future experimental
investigations. This study significantly contributes to our understandings of
the spectroscopic properties of -wave charmed baryons.Comment: 10 pages, 2 figures, 9 tables. More references added. Accepted by
Phys. Rev.
The newly observed : A good candidate for a -wave charmed baryon
The newly observed gives us a good chance to construct the
charmed baryon family. In this work, we carry out the mass spectrum
analysis by a non-relativistic potential model using Gaussian Expansion Method,
and the study of its two-body Okubo-Zweig-Iizuka allowed strong decay behavior.
Our results imply that the is good candidate of
state with . We also predict the spectroscopy behavior of other
states, which may provide further clues to their search.Comment: 6 pages, 4 tables, 3 figures. Accepted by PR
A new scoring function for top-down spectral deconvolution
BACKGROUND: Top-down mass spectrometry plays an important role in intact protein identification and characterization. Top-down mass spectra are more complex than bottom-up mass spectra because they often contain many isotopomer envelopes from highly charged ions, which may overlap with one another. As a result, spectral deconvolution, which converts a complex top-down mass spectrum into a monoisotopic mass list, is a key step in top-down spectral interpretation.
RESULTS: In this paper, we propose a new scoring function, L-score, for evaluating isotopomer envelopes. By combining L-score with MS-Deconv, a new software tool, MS-Deconv+, was developed for top-down spectral deconvolution. Experimental results showed that MS-Deconv+ outperformed existing software tools in top-down spectral deconvolution.
CONCLUSIONS: L-score shows high discriminative ability in identification of isotopomer envelopes. Using L-score, MS-Deconv+ reports many correct monoisotopic masses missed by other software tools, which are valuable for proteoform identification and characterization
Systematic Evaluation of Protein Sequence Filtering Algorithms for Proteoform Identification Using Top-Down Mass Spectrometry
Complex proteoforms contain various primary structural alterations resulting from variations in genes, RNA, and proteins. Top-down mass spectrometry is commonly used for analyzing complex proteoforms because it provides whole sequence information of the proteoforms. Proteoform identification by top-down mass spectral database search is a challenging computational problem because the types and/or locations of some alterations in target proteoforms are in general unknown. Although spectral alignment and mass graph alignment algorithms have been proposed for identifying proteoforms with unknown alterations, they are extremely slow to align millions of spectra against tens of thousands of protein sequences in high throughput proteome level analyses. Many software tools in this area combine efficient protein sequence filtering algorithms and spectral alignment algorithms to speed up database search. As a result, the performance of these tools heavily relies on the sensitivity and efficiency of their filtering algorithms. Here, we propose two efficient approximate spectrum-based filtering algorithms for proteoform identification. We evaluated the performances of the proposed algorithms and four existing ones on simulated and real top-down mass spectrometry data sets. Experiments showed that the proposed algorithms outperformed the existing ones for complex proteoform identification. In addition, combining the proposed filtering algorithms and mass graph alignment algorithms identified many proteoforms missed by ProSightPC in proteome-level proteoform analyses
New type of hydrogenlike charm-pion or charm-kaon matter
Borrowing the structures of the hydrogen atom, molecular ion, and diatomic
molecule, we predict the nature of a new type of hydrogenlike charm-pion or
charm-kaon matter that could be obtained by replacing the proton and electron
in hydrogen matter with a charmed meson and a pion or a kaon, respectively. We
find that the spectra of the atom, molecular ion, and diatomic molecule can be
obtained simultaneously with the Coulomb potential for the hydrogen, the
charm-pion, and the charm-kaon systems. The predicted charm-pion matter also
allows us to explore the mass shift mediated by the strong interaction. For the
charm-pion and charm-kaon systems, the strong interactions could lead to
binding energy shifts. Our calculations suggests that the binding energy shifts
in charm-pion systems are in the order of several to tens of eV. For the
charm-kaon systems, the results are in the order of tens to hundreds of eV.
Exploring hydrogenlike charm-pion matter must lead to new demands for
high-precision experiments.Comment: 5 pages, 4 figures and 1 table. Typos corrected. Accepted by Phys.
Rev.
Universal behavior of mass gaps existing in the single heavy baryon family
The mass gaps existing in the discovered single heavy flavor baryons are
analyzed, which show some universal behaviors. Under the framework of a
constituent quark model, we quantitatively explain why such interesting
phenomenon happens, when these established excited heavy baryons are regarded
as the -mode excitations. Based on the universal behaviors of the
discussed mass gaps, we may have three implications including the prediction of
the masses of excited baryons which are still missing in the
experiment. For completeness, we also discuss the mass gaps of these
-mode excited single heavy flavor baryons.Comment: 11 pages, 7 tables and 1 figur
Double-charm heptaquark states composed of two charmed mesons and one nucleon
Inspired by the experimental discoveries of , , and
and the theoretical picture where they are , , and
molecular candidates, we investigate the double charm heptaquark system
of . We employ the one-boson-exchange model to deduce the pairwise
-, -, and - potentials and then study the system
with the Gaussian expansion method. We find two good hadronic molecular
candidates with and
with only -wave pairwise interactions.
The conclusion remains unchanged even taking into account the - mixing
and coupled channel effects. In addition to providing the binding energies, we
also calculate the root-mean-square radii of the system, which further
support the molecular nature of the predicted states. They can be searched for
at the upcoming LHC run 3 and run 4.Comment: 9 pages, 4 figures, 2 table
Radiative decays and magnetic moments of the predicted -like molecules
In this work, we first perform a systematic study of the transition magnetic
moments and the corresponding radiative decay behaviors of the -like
molecular states associated with their mass spectra, where the constituent
quark model is adopted by considering the - wave mixing effect. Our
numerical results show that the radiative decay properties can be considered as
the effective physical observable to reflect the inner structures of these
-like molecular states. Meanwhile, we also discuss the magnetic moments of
the -like molecular states, and we find that the magnetic moment
properties can be used to distinguish the -like molecular states from the
conventional mesonic states, which have the same quantum numbers and
similar masses. We expect that the present study can inspire the interest of
experimentalist in exploring the electromagnetic properties of the -like
molecular states, especially the radiative decay properties.Comment: 13 pages, 8 tables, 1 figur
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