Hasil untuk "hep-ph"

Wolfgang Bietenholz

Researchers working in lattice field theory constitute an established community since the early 1990s, and around the same time the online open-access e-print repository arXiv was created. The fact that this field has a specific arXiv section, hep-lat, which is comprehensively used, provides a unique opportunity for a statistical study of its evolution over the last three decades. We present data for the number of entries, $E$, published papers, $P$, and citations, $C$, in total and separated by nations. We compare them to six other arXiv sections (hep-ph, hep-th, gr-qc, nucl-th, quant-ph, cond-mat) and to two socio-economic indices of the nations involved: the Gross Domestic Product (GDP) and the Education Index (EI). We present rankings, which are based either on the Hirsch Index H, or on the linear combination $Σ= E + P + 0.05 C$. We consider both extensive and intensive national statistics, i.e. absolute and relative to the population or to the GDP.

A. Tureanu

Recently, our work regarding the definition of oscillating neutrino states in Eur. Phys. J. C 80: 68 (2020), arXiv:1902.01232 [hep-ph] has been commented upon in arXiv:2004.04739 [hep-ph]. In this note we show that, contrary to the claim in the comment, our above-mentioned work cannot be reproduced in the scheme of the so-called flavour Fock space approach described in the comment. Moreover, we prove explicitly that a flavour Fock space cannot exist in a model with massive mixed neutrinos. If the flavour Fock space scheme were viable, it would necessarily lead, as a consequence of Coleman's theorem, to the flavour number invariance of the Hamiltonian of mixed neutrino fields, while the Hamiltonian is by construction flavour number violating. Quod est absurdum.

Karim Benakli

We point out the peculiar form of the gravitational wave signal expected from a gas of particles carry spin 3/2 produced during preheating. Given the very few ways that gravitinos can manifest themselves in an experimentally observable way, we stress the importance of improving the sensitivity of ultra-high frequency detectors in the future. This review is based on work that appeared in [arXiv:1811.11774 [hep-ph]].

Ngoc The Nguyen, N. Nguyen, Ngo The Nhan Tran et al.

Nanogel-based systems loaded with single anticancer drugs display miscellaneous effectiveness in tumor remission, gradually circumventing mutation and resistance in chemotherapy. Hence, the existence of dual-drug delivered nano-sized systems has been contemporaneous with drug development and preceded the conventional-dose chemotherapy. Among outstanding synergistic drug nanoplatforms, thermosensitive copolymer heparin-Pluronic F127 (Hep-F127) co-delivering cisplatin (CDDP) and curcumins (Cur) (Hep-F127/CDDP/Cur) has emerged as a notable candidate for temperature-responsive drug delivery. The procedure was based on the entrapment of curcumin into the hydrophobic core of bio-degradable co-polymer Hep-F127 while the hydrophilic drug CDDP subsequently conjugated to the backbone heparin to form the core-shell structure. The copolymer was characterized by Fourier transform infrared (FT-IR) spectrophotometry, Transmission Electron Microscopy (TEM), and Dynamic Light Scattering (DLS), to corroborate the successful synthesis and via HPLC along with AES-ICP to evaluate the high drug loading along with a controllable release from the nano-gels. A well-defined nano-shell with size in the 129.3 ± 3.8 nm size range could enhance higher the efficacy of the conjugated-CDDP to Hep-F127 than that of single doses. Moreover, the considerable amount of dual-drug released from thermosensitive nanogels between different conditions (pH = 7.4 and pH = 5.5) in comparison to CDDP from Hep-F127 partially indicated the significantly anti-proliferative ability of Hep-F127/CDDP/Cur to the MCF-7 cell line. Remarkably, drug testing in a xenograft model elucidates the intricate synergism of co-delivery in suppressing tumor growth, which remedies some of the problems affecting in cancer chemotherapy.

Caterina Doglioni

One overarching objective of science is to further our understanding of the universe, from its early stages to its current state and future evolution. This depends on gaining insight on the universe's most macroscopic components, for example galaxies and stars, as well as describing its smallest components, namely elementary particles and nuclei and their interactions. It is clear that this endeavour requires combined expertise from the fields of astroparticle physics, particle physics and nuclear physics. Pursuing common scientific drivers also require mastering challenges related to instrumentation (e.g. beams and detectors), data acquisition, selection and analysis, and making data and results available to the broader science communities. Joint work and recognition of these "foundational" topics will help all communities grow towards their individual and common scientific goals. The talk corresponding to this contribution has been presented during the special ECFA session of EPS-HEP 2019 focused on the update of the European Strategy of Particle Physics.

R. N. Lee, A. I. Onishchenko

We argue that in many physical calculations where the "eliptic" sectors are involved, one can express the results via iterated integrals with almost all weights being rational. Our method is based on the existence of $ε$-regular basis, which is akin to the $ε$-finite basis defined in Ref. [hep-ph/0601165]. As a demonstration of our technique, we calculate the photon contribution to the total cross section of the production of two $Q\bar Q$ pairs in the electron-positron collisions.

M. Jay Pérez, Moinul Hossain Rahat, Pierre Ramond et al.

We propose $\mathcal{T}_{13} = \mathcal{Z}_{13} \rtimes \mathcal{Z}_3$ as the underlying non-Abelian discrete family symmetry of the asymmetric texture presented in arXiv:1805.10684 [hep-ph]. Its mod 13 arithmetic distinguishes each Yukawa matrix element of the texture. We construct a model of effective interactions that singles out the asymmetry and equates, without fine-tuning, the products of down-quark and charged-lepton masses at a GUT-like scale.

Nhat-Anh N. Tong, N. Tran, X. Nguyen et al.

P. Cameron, Strongarm Studios

G. Chachamis

We present some of the topics covered in a series of lectures under the same title that was given at the "Summer School on High Energy Physics at the LHC: New trends in HEP" in Natal, Brazil. In particular, after some general thoughts on phenomenology we give a pedagogical introduction to the BFKL formalism and we discuss recent BFKL phenomenological studies for LHC observables.

A. Tavanti, G. Maisetta, Gaetano Del Gaudio et al.

V. Uzhinsky, A. Galoyan

Unified systematic of elastic scattering data (USESD) proposed by the authors (arxiv:1111.4984 [hep-ph]) is based on symmetrized 2-dimensional Fermi distribution for pp elastic scattering amplitude in the impact parameter representation. It allows to describe differential cross sections of the reactions up to |t| ~ 1.75 (GeV/c)$^2$. To extend it to higher |t| values we consider a two coherent exponential parametrization of the cross sections and show that it cannot describe the cross sections at small |t| at $P_{lab}>$ 10 GeV/c. We extract a description of high |t| region from the parameterization and couple it with USESD. As a result, we obtained a good description of all pp elastic scattering data at $P_{lab}>$ 10 GeV/c. It can be easily used in Glauber Monte Carlo codes for calculations of nucleus-nucleus interaction properties.

Z. Bern, G. Diana, L. J. Dixon et al.

We extend our investigation of backgrounds to new physics signals, following CMS's data-driven search for supersymmetry at the LHC. The aim is to use different sets of cuts in gamma + 3-jet production to predict the irreducible Z + 3-jet background (with the Z boson decaying to neutrinos) to searches with missing transverse energy + 3-jet signal topologies. We compute ratios of Z + 3-jet to gamma + 3-jet production cross sections and kinematic distributions at next-to-leading order (NLO) in alpha_s. We compare these ratios with those obtained using a parton shower matched to leading-order matrix elements (ME+PS). This study extends our previous work [arXiv:1106.1423 [hep-ph]] on the Z + 2-jet to gamma + 2-jet ratio. We find excellent agreement with the ratio determined from the earlier NLO results involving two instead of three jets, and agreement to within 10% between the NLO and ME+PS results for the ratios. We also examine the possibility of large QCD logarithms in these processes. Ratios of Z + n-jet to gamma + n-jet cross sections are plausibly less sensitive to such corrections than the cross sections themselves. Their effect on estimates of Z + 3-jet to gamma + 3-jet ratios can be assessed experimentally by measuring the gamma + 3-jet to gamma + 2-jet production ratio in search regions. We partially address the question of potentially large electroweak logarithms by computing the real-emission part of the electroweak corrections to the ratio using ME+PS, and find that it is 1% or less. Our estimate of the remaining theoretical uncertainties in the Z to gamma ratio is in agreement with our earlier study.

M. Lundin, E. Blomberg, R. Tilton

P. Kruse, E. Miedema

Dense populations containing 129 x 106 Jensen sarcoma, 134 x 106 DON Chinese hamster, 28.9 x 106 WI-38 human diploid, 61.8 x 106 HEp-2 human carcinoma, and 67.4 x 106 WISH human amnion cells were produced from dilute inocula, 0.85 to 5.33 x 106, in 7 to 8 days in a perfusion system using replicate T-60 flasks. Perfusion rates as high as 560 ml medium/day/T-60 were required to maintain pH (to ca ±0.1 unit) and adequate nutrient supplies. The cell densities encountered are described by the term "monolayer equivalents" (M.E.), defined as number of cells per culture divided by number of cells in a monolayer. The M.E.'s for T-60 cultures containing unusually dense populations of 40 x 106 WI-38 and 250 x 106 DON cells (9-day perfusion) were 5 and 17, respectively, and numbers of cells in illustrations of stained cross-sections of membranes from these cultures were in excellent agreement. Threshold M.E.'s exist below which proliferation is the chief cellular activity and above which one or more cell functions may predominate even though proliferation persists. Cellular nutrition and metabolism may change with changes in M.E., as illustrated in different patterns of glutamic acid, proline, and glycine utilization or production in dense vs. dilute WI-38 cell populations. The results indicated that the role of contact inhibition phenomena in arresting cellular proliferation was diminished in perfusion system environments.

H. Namdari, E. J. Bottone

Edwin H. W. Leung, Nguyen T.B

B. Bode, D. Kaminski, W. Souba et al.

Andrei Linde, M. Sasaki, Takahiro Tanaka

The possibility to have an infinite open inflationary universe inside a bubble of a finite size is one of the most interesting realizations extensively discussed in the literature. The original idea was based on the theory of tunneling and bubble formation in the theories of a single scalar field. However, for a long time we did not have any consistent models of this type, so it was impossible to compare predictions of such models with the observational data on the CMB anisotropy. The first semi-realistic model of this type was proposed only very recently, in hep-ph/9807493. Here we present the results of our investigation of the scalar and tensor perturbation spectra and the resulting CMB anisotropy in such models. In all models which we have studied there are no supercurvature perturbations. The spectrum of scalar CMB anisotropies has a minimum at small l and a plateau at l > O(10) for low Omega_0. Meanwhile tensor CMB anisotropies are peaked at l=2. Relative magnitude of the scalar CMB spectra versus tensor CMB spectra at small l depends on the parameters of the models.

S. Eidelman, F. Jegerlehner, A. Kataev et al.

Abstract Based on the compilation of the available e + e − data [S.I. Eidelman, F. Jegerlehner, Z. Phys. C 67 (1995) 585; F. Jegerlehner, Nucl. Phys. B (Proc. Suppl.) 51C (1996) 131], we present a non-perturbative estimation of the Adler function derived from the electromagnetic current correlator, and compare it with theoretical predictions from perturbative QCD (pQCD). The comparison is presented for the Euclidean region where pQCD is supposed to work best. We emphasize that such a comparison only makes sense if one takes into account the exact mass dependence of the perturbative predictions, which are available for the leading and next to leading (two-loop) order. In order to have the correct physical mass dependence in the evolution of the strong coupling as well, we utilize the MOM scheme β -function to two-loops calculated recently [F. Jegerlehner, O.V. Tarasov, DESY 98-093, hep-ph/9809485, and references therein]. Three-loop effects, which are available as series expansions for low [K.G. Chetyrkin et al., Nucl. Phys. B 482 (1996) 213; B 505 (1997) 40] and high [K.G. Chetyrkin et al., Nucl. Phys. B 503 (1997) 339] momentum transfer, are included by using Pade improvement. We discuss possible constraints on non-perturbative effects as suggested by the operator product expansion.