Searcharxiv⌕ Search

arXiv subjects

T. Mizoguchi

Publications and source records attributed to T. Mizoguchi.

At least 19 recordsLinked to original sources
arXiv2020

Multiplicity distribution in pseudo-rapidity windows and charge conservation

Charged multiplicity distribution in a pseudo-rapidity window is formulated under the assumption that the charge conservation is satisfied in the full phase space. At first, we analyze measured charged particle multiplicity distributions in pseudo-rapidity windows in LHC by CMS and ALICE collaborations with the two probability distributions. One is the convolution of negative binomial and Poisson distributions, and the other is the Glauber-Lachs formula. Each distribution is considered as an analogy of the quantum optics. Next, we analyze the data with the double GL formulae for $|η|<2.4$ at 7 TeV by the CMS collaboration and for $|η|<1.5$ at 8 TeV by the ALICE collaboration to describe the global structure of measured distributions.

hep-ph↗
arXiv2020

Local thickness and composition measurements from scanning convergent-beam electron diffraction of a binary non-crystalline material obtained by a pixelated detector

We measured the local composition and thickness of SiO2-based glass material from diffraction. By using four dimensional scanning transmission electron microscopy (4D-STEM), we obtained diffraction at each scanning point. Comparing the obtained diffraction with simulated diffraction patterns, we try to measure the local composition and thickness. Although this method requires some constraints, this method measured local composition and thickness with 1/10 or less electron dose of EELS.

cond-mat.mtrl-sci↗
arXiv2009

A potential including Heaviside function in 1+1 dimensional hydrodynamics by Landau

In 1+1 dimensional hydrodynamics originally proposed by Landau, we derive a new potential and distribution function including Heaviside function and investigate its mathematical and physical properties. Using the original distribution derived by Landau, a distribution function found by Srivastava et al., our distribution function, and the Gaussian distribution proposed by Carruthers et al., we analyze the data of the rapidity distribution on charged pions and K mesons at RHIC energies (sqrt(s_NN) = 62.4 GeV and 200 GeV). Three distributions derived from the hydrodynamics show almost the same chi-squared values provided the CERN MINUIT is used. We know that our calculations of hadron's distribution do not strongly depend on the range of integration of fluid rapidity, contrary to that of Srivastava et al. Finally the roles of the Heaviside function in concrete analyses of data are investigated.

hep-ph↗
arXiv2007

Spin configuration in a frustrated ferromagnetic/antiferromagnetic thin film system

We have studied the magnetic configuration in ultrathin antiferromagnetic Mn films grown around monoatomic steps on an Fe(001) surface by spin-polarized scanning tunneling microscopy/spectroscopy and ab-initio-parametrized self-consistent real-space tight binding calculations in which the spin quantization axis is independent for each site thus allowing noncollinear magnetism. Mn grown on Fe(001) presents a layered antiferromagnetic structure. In the regions where the Mn films overgrows Fe steps the magnetization of the surface layer is reversed across the steps. Around these defects a frustration of the antiferromagnetic order occurs. Due to the weakened magnetic coupling at the central Mn layers, the amount of frustration is smaller than in Cr and the width of the wall induced by the step does not change with the thickness, at least for coverages up to seven monolayers.

cond-mat.mtrl-sci↗
arXiv2006

Modified Hagedorn formula including temperature fluctuation - Estimation of temperatures at RHIC experiments -

We have systematically estimated the possible temperatures obtained from an analysis of recent data on $p_t$ distributions observed at RHIC experiments. Using the fact that observed $p_t$ distributions cannot be described by the original Hagedorn formula in the whole range of transverse momenta (in particular above 6 GeV/c), we propose a modified Hagedorn formula including temperature fluctuation. We show that by using it we can fit $p_t$ distributions in the whole range and can estimate consistently the relevant temperatures, including their fluctuations.

hep-ph↗
arXiv2005

Local thermalization in d + Au collisions

The extent of a locally equilibrated parton plasma in d + Au collisions at sqrt(s_NN) = 200 GeV is investigated as a function of centrality in a nonequilibrium-statistical framework. Based on a three-sources model, analytical solutions of a relativistic diffusion equation are in precise agreement with recent data for charged-particle pseudorapidity distributions. The moving midrapidity source indicates the size of the local thermal equilibrium region after hadronization. In central d + Au collisions it contains 19% of the produced particles.

hep-ph↗
arXiv2004

Analyses of two and three pion Bose-Einstein Correlations using Coulomb wave functions

Using effective formulas we analyze the Bose-Einstein correlations (BEC) data corrected for Coulomb interactions provided by STAR Collaboration and the quasi-corrected data (raw data with acceptance correction etc) on 2πand 3πBEC by using Coulomb wave function with coherence parameter included. The corresponding magnitudes of the interaction regions turn out to be almost the same: R_{Coul}(2π) \simeq \frac 32R_{Coul}(3π). R_{Coul} means the size of interaction region obtained in terms of Coulomb wave function. This approximate relation is also confirmed by the core-halo model. Moreover, the genuine 3rd order term of BEC has also been investigated in this framework and its magnitude has been estimated both in the fully corrected data and in the quasi-corrected data.

nucl-th↗
arXiv2004

Analysis of distribution of cosmic microwave background photon in terms of non-extensive statistics and formulas with temperature fluctuation

To take into account the temperature fluctuation in the Planck distribution, we calculate convolution integral with several probability distributions. Using these formula as well the Planck distribution and a formula in the non-extensive statistics, we analyze the data measured by the Cosmic Background Explorer (COBE). Our analysis reveals that the derivation from the Planck distribution is estimated as |q-1| = 4.4\times 10^{-5}, where q means the magnitude of the non-extensivity or the temperature fluctuation, provided that the dimensionless chemical potential proposed by Zeldovich and Sunyaev exists. Comparisons of new formulas and the Planck distribution including the Sunyaev-Zeldovich (S-Z) effect are made.

cond-mat.stat-mech↗
arXiv2003

Possible formulations for three-charged particles correlations in terms of Coulomb wave functions

The recent data for Bose-Einstein Correlations (BEC) of three-charged particles obtained by NA44 Collaboration have been analysed using theoretical formula with Coulomb wave functions. It has been recently proposed by Alt et al. It turns out that there are discrepancies between these data and the respective theoretical values. To resolve this problem we seek a possibly modified theoretical formulation of this problem by introducing the degree of coherence for the exchange effect due to the BEC between two-identical bosons. As a result we obtain a modified formulation for the BEC of three-charged particles showing good agreement with the data. Moreover, we investigate physical connection between our modified formulation and the core-halo model proposed by Csorgo et al. Our study indicates that the interaction region estimated by the BEC of three-charged particles in the S + Pb collisions at 200 GeV/c per nucleon is equal to about 1.5 fm~1.8 fm.

hep-ph↗
arXiv2003

A formulation for description of pi^+(2pi^-) and pi^-(2pi^+) channels in Bose-Einstein correlation by Coulomb wave function

In order to analyze data on charged pions correlation channels, pi^+(2pi^-) and pi^-(2pi^+), we propose new interferometry approach using the Coulomb wave function. We show that to describe adequately data we have to introduce new parameter describing the contribution of pi^-(k_1) pi^+(k_2) --> pi^-(k_2) pi^+(k_1) process. Using this new formula we analyze data on pi^+(2pi^-) and pi^-(2pi^+) channels at sqrt(s) = 91 GeV by DELPHI Collaboration, and estimate the magnitude of this new parameter as well as the degree of coherence.

hep-ph↗
arXiv2003

Analyses of $dN_{ch}/dη$ and $dN_{ch}/dy$ distributions of BRAHMS Collaboration by means of the Ornstein-Uhlenbeck process

Interesting data on $dN_{\rm ch}/dη$ in Au-Au collisions ($η=-\ln \tan (θ/2)$) with the centrality cuts have been reported by BRAHMS Collaboration. Using the total multiplicity $N_{\rm ch} = \int (dN_{\rm ch}/dη)dη$, we find that there are scaling phenomena among $(N_{\rm ch})^{-1}dN_{\rm ch}/dη= dn/dη$ with different centrality cuts at $\sqrt{s_{NN}} =$ 130 GeV and 200 GeV, respectively. To explain these scaling behaviors of $dn/dη$, we consider the stochastic approach named the Ornstein-Uhlenbeck process with two sources. The following Fokker-Planck equation is adopted for the present analyses, $$ \frac{\partial P(x,t)}{\partial t} = γ[\frac{\partial}{\partial x}x + \frac 12\frac{σ^2}γ\frac{\partial^2}{\partial x^2}] P(x, t) $$ where $x$ means the rapidity (y) or pseudo-rapidity ($η$). $t$, $γ$ and $σ^2$ are the evolution parameter, the frictional coefficient and the variance, respectively. Introducing a variable of $z_r = η/η_{\rm rms}$ ($η_{\rm rms}=\sqrt{< η^2 >}$) we explain the $dn/d z_r$ distributions in the present approach. Moreover, to explain the rapidity (y) distributions from $η$ distributions at 200 GeV, we have derived the formula as $$ \frac{dn}{dy}=J^{-1}\frac{dn}{d η}, $$ where $J^{-1}=\sqrt{M(1+\sinh^2 y)}/\sqrt{1+M\sinh^2 y}$ with $M = 1 + (m/p_{\rm t})^2$. Their data of pion and all hadrons are fairly well explained by the O-U process. To compare our approach with another one, a phenomenological formula by Eskola et al. is also used in calculations of $dn/dη$.

nucl-th↗
arXiv2002

Scaling Behavior of $(N_{ch})^{-1}dN_{ch}/dη$ at $\sqrt{s_{NN}} = 130$ GeV by the PHOBOS Collaboration and Its Implication --A Possible Explanation Employing the Ornstein-Uhlenbeck Process--

Recently, interesting data concerning $dN_{ch}/dη$ in Au-Au collisions [$η=-\ln \tan (θ/2)$] with centrality cuts have been reported from the PHOBOS Collaboration. In most treatment these data are divided by the number of participants (nucleons) in collisions. Instead of this method, we use the total multiplicity $N_{ch} = \int (dN_{ch}/dη)dη$ and find that there is scaling phenomenon among $(N_{ch})^{-1}dN_{ch}/dη= dn/dη$ with different centrality cuts at $\sqrt{s_{NN}} = 130$ GeV. To explain this scaling behavior of $dn/dη$, we employ a stochastic approach using the Ornstein-Uhlenbeck process with two sources. A Langevin equation is adopted for this explanation. Moreover, comparisons of $dn/dη$ at $\sqrt{s_{NN}} = 130$ GeV with that at $\sqrt{s_{NN}} = 200$ GeV are made, and no significant difference is found. A possible method fot the detection of the quark-gluon plasma (QGP) through $dN_{ch}/dη$ is presented.

nucl-th↗
arXiv2001

Scaling behavior of $(N_{ch})^{-1}dN_{ch}/dη$ at $\sqrt{s_{NN}} = 130$ GeV by PHOBOS Collaboration and its analyses in terms of stochastic approach

Recently interesting data on $dN_{ch}/dη$ in Au-Au collisions ($η=-\ln \tan (θ/2)$) with the centrality cuts have been reported by PHOBOS Collaboration. Their data are usually divided by the number of participants (nucleons) in collisions. Instead of this way, using the total multiplicity $N_{ch} = \int (dN_{ch}/dη)dη$, we find that there is scaling phenomenon among $(N_{ch})^{-1}dN_{ch}/dη= dn/dη$ with different centrality cuts at $\sqrt{s_{NN}} = 130$ GeV. To explain this scaling behavior of $dn/dη$, we consider the stochastic approach called the Ornstein-Uhlenbeck process with two sources. Moreover, comparisons of $dn/dη$ at $\sqrt{s_{NN}} = 130$ GeV with that at $\sqrt{s_{NN}} = 200$ GeV have been made. A possible detection method of the quark-gluon plasma (QGP) thorough $dn/dη$ is presented.

hep-ph↗
arXiv2001

Analyses of multiplicity distributions at Tevatron by a two-component stochastic model --- No leading particle effect in E735 Experiment ---

Comparisons of multiplicity distributions at sqrt(s) = 1.8 TeV (E735 Experiment and CDF Collaboration) with our predictions by a two-component stochastic model have been made. This stochastic model is described by the pure-birth and Poisson processes. It is found that there are discrepancies among data at the CERN Sp-bar-pS collider and those at the Tevatron collider. The latter data by E735 do not contain the leading particle effect described by the Poisson process, providing that the view of the two-component stochastic model is correct. The data by CDF contain small leading particle effect. The reason is probably attributed to the correction made by E735, which is necessary to make the data of the full phase space from the restricted rapidity |eta|<3.25.

hep-ph↗
arXiv1999

Analysis of correlation data of pi^+pi^- pair in p + Ta reaction using Coulomb wave function including momentum resolution and strong interaction effect

We have proposed a new method for the Coulomb wave function correction which includes the momentum resolution for charged hadron pairs and applied it to the precise data on pi^+pi^- correlations obtained in p + Ta reaction at 70 GeV/c. It is found that interaction regions of this reaction (assuming Gaussian source function) are 9.8+-5.8 fm and 7.7+-4.8 fm for the thicknesses of the target 8 micro m and 1.4 micro m, respectively. We have also analyzed the data by the formula including strong interaction effect. The physical picture of the source size obtained in this way is discussed.

nucl-th↗
arXiv1997

Final State Interactions in Bose-Einstein Correlations

We are presenting here the new formulae for Bose-Einstein correlations (BEC) which contain effects of final state interactions (FSI) of both strong (in $s$-wave) and electromagnetic origin. We demonstrate the importance of FSI in BEC by analysing data for $e^+e^-$ annihilation and for heavy collisions. The inclusion of FSI results in the practical elimination (at least in $e^+e^-$ data) of the so called degree of coherence parameter $λ$ (which becomes equal unity) and the long range parameter $γ$ (which is now equal zero).

hep-ph↗