Dr. Alejandro Raul Hernandez-Montoya

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Academic Career Length

32Years (1995-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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3 April 1995 in Physical Review Letters

Journal Article

Observation of the Top Quark

S. Abachi

B. Abbott

M. Abolins

B. S. Acharya

I. Adam

A. Zylberstejn

+397

The D0 Collaboration reports on a search for the standard model top quark in

p \bar{p}

collisions at

\sqrt{s} = 1.8 TeV

at the Fermilab Tevatron with an integrated luminosity of approximately

50 {pb}^{- 1}

. We have searched for

t \bar{t}

production in the dilepton and single-lepton decay channels with and without tagging of

b

-quark jets. We observed 17 events with an expected background of

3.8 \pm 0.6

events. The probability for an upward fluctuation of the background to produce the observed signal is

2 \times 10^{- 6}

(equivalent to 4.6 standard deviations). The kinematic properties of the excess events are consistent with top quark decay. We conclude that we have observed the top quark and measured its mass to be

199_{- 21}^{+ 19}

(stat)

\pm 22

(syst)

GeV {/ c}^{2}

and its production cross section to be

6.4 \pm 2.2 pb

14 July 1999 in Physical Review D

Journal Article

Measurement of the top quark mass in the dilepton channel

B. Abbott

M. Abolins

V. Abramov

B. S. Acharya

I. Adam

A. Zylberstejn

+365

We report a measurement of the top quark mass using six candidate events for the process

p \bar{p} \to t \bar{t} + \vec{X} l^{+} ν {bl}^{-} \bar{ν} \bar{b} + X

, observed in the D0 experiment at the Fermilab

p \bar{p}

collider. Using maximum likelihood fits to the dynamics of the decays, we measure a mass for the top quark of

m_{t} = 168.4 \pm 12.3 (stat) \pm 3.6 (syst) Gev

. We combine this result with our previous measurement in the

t \bar{t} \to l + jets

channel to obtain

m_{t} = 172.1 \pm 7.1 GeV

as the best value of the mass of the top quark measured by D0.

23 July 1998 in Physical Review D

Journal Article

Direct measurement of the top quark mass by the DØ Collaboration

B. Abbott

M. Abolins

B. S. Acharya

I. Adam

D. L. Adams

A. Zylberstejn

+368

We determine the top quark mass

m_{t}

using

t \bar{t}

pairs produced in the DØ detector by

\sqrt{s} = 1.8 TeV

p \bar{p}

collisions in a

125 {pb}^{- 1}

exposure at the Fermilab Tevatron. We make a two constraint fit to

m_{t}

t \bar{t} \to {bW}^{+} \bar{b} W^{-}

final states with one W boson decaying to

q \bar{q}

and the other to

e ν

μ ν .

Likelihood fits to the data yield

m_{t} (l + jets) = 173.3 \pm 5.6 (stat) \pm 5.5 (syst) GeV {/ c}^{2} .

When this result is combined with an analysis of events in which both W bosons decay into leptons, we obtain

m_{t} = 172.1 \pm 5.2 (stat) \pm 4.9 (syst) GeV {/ c}^{2} .

An alternate analysis, using three constraint fits to fixed top quark masses, gives

m_{t} (l + jets) = 176.0 \pm 7.9 (stat) \pm 4.8 (syst) GeV {/ c}^{2},

consistent with the above result. Studies of kinematic distributions of the top quark candidates are also presented. 14.65.Ha, 13.85.Ni, 13.85.Qk

18 August 1997 in Physical Review Letters

Journal Article

Direct Measurement of the Top Quark Mass

S. Abachi

B. Abbott

M. Abolins

B. S. Acharya

I. Adam

A. Zylberstejn

+375

We measure the top quark mass

m_{t}

using

t \bar{t}

pairs produced in the D0 detector by

\sqrt{s} = 1.8 TeV p \bar{p}

collisions in a

125 {pb}^{- 1}

exposure at the Fermilab Tevatron. We make a two constraint fit to

m_{t}

t \bar{t} \to {bW}^{+} \bar{b} W^{-}

final states with one W decaying to

q \bar{q}

and the other to

e ν

μ ν

. Events are binned in fit mass versus a measure of probability for events to be signal rather than background. Likelihood fits to the data yield

m_{t} = 173.3 \pm 5.6 (stat) \pm 6.2 (syst) GeV {/ c}^{2}

24 July 1995 in Physical Review Letters

Journal Article

Search for Squarks and Gluinos in

p \bar{p}

Collisions at

\sqrt{s} = 1.8 TeV

S Abachi

B Abbott

M Abolins

B Acharya

I Adam

A Zylberstejn

+390

We present a search for events consistent with the production and decay of the squarks and gluinos of the minimal supersymmetric standard model (MSSM) in the D0 detector at the Fermilab Tevatron

p \bar{p}

collider. We examined data for events containing large missing transverse energy and three or more jets. We observed no excess of events above the expected yield from standard model processes. For a choice of MSSM parameter values, we set a lower limit at the 95% confidence level on the mass of the gluino of 144 GeV

{/ c}^{2}

for all squark masses and a lower limit of 212 GeV

{/ c}^{2}

for equal squark and gluino masses.

11 January 2000 in Physical Review D

Journal Article

Measurement of the inclusive differential cross section forZbosons as a function of transverse momentum in

\bar{p} p

collisions at

\sqrt{s} = 1.8

TeV

B. Abbott

M. Abolins

V. Abramov

B. S. Acharya

I. Adam

A. Zylberstejn

+354

We present a measurement of the differential cross section as a function of transverse momentum of the Z boson in

p \bar{p}

collisions at

\sqrt{s} = 1.8

TeV using data collected by the DØ experiment at the Fermilab Tevatron Collider during 1994–1996. We find good agreement between our data and the next-to-next-to-next-leading-logarithmic resummation prediction and extract values of the non-perturbative parameters for the resummed prediction from a fit to the differential cross section.

About Me

Name: Alejandro Raúl Hernández Montoya Current Position: Full Professor at Research Institute on Artificial Intelligence. Universidad Veracruzana. Mexico. Education: 1993-1997: PhD in Physics, Departamento de Fı́sica del Centro de Investigación y de Estudios Avanzados del I.P.N. CINVESTAV. México, D.F. 1990-1992: Msc Degree, Physics. Departamento de Fı́sica del CINVESTAV. México D.F. 1982-1987: Bs Degree. Mathematics. Facultad de Matemáticas de la Universidad Veracruzana. Xalapa, Veracruz. Work Experience: Teaching at levels of undergraduate and graduate studies (master and doctorate degrees). Impartition of National and international scientific talks and for invitation. Thesis direction of bachelor, master and PhD. Responsible of national and international scientific projects. Author of more than 80 research papers in prestigious indexed journals. Participation in the high energy experiments E791 and Dzero at Fermilab, in Batavia, Illinois USA and ALICE at (CERN) in Geneve, Switzerland. Editor and referee of international, indexed journals. Memberships and awards: Member of the National System of Researchers (SNI), Mexican Academy of Sciences, the Scientific Society Sigma Xi, and the International Center of Sciences (CIC AC). Research lines of Interest: Mathematical Physics and Computational Physics, Statistical Mechanics and Complex Systems, Applications of Physics to Economics (Econophysics), Stochastic Processes. Recently: Computational Number Theory

Dr. Alejandro Raul Hernandez-Montoya

Dr. Alejandro Raul Hernandez-Montoya

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