[Tex/LaTex] Which latex character is this

Question

I am trying to find out which latex character I should use to produce this X:

I tried using this web-site but couldn't find the exact same thing. http://detexify.kirelabs.org/classify.html

My best guesses are:

\chi
\mathcal{X}

but both of them are different than the image.

UPDATE:

When I try to build,

\documentclass{article}
\DeclareMathAlphabet{\mathpzc}{OT1}{pzc}{m}{it}
\begin{document}

$\mathpzc{X}$

\end{document}

I get the following error,

Saits-MacBook-Pro:Desktop sait$ pdflatex a.tex
This is pdfTeX, Version 3.14159265-2.6-1.40.15 (TeX Live 2014) (preloaded format=pdflatex)
 restricted \write18 enabled.
entering extended mode
(./a.tex
LaTeX2e <2014/05/01>
Babel <3.9k> and hyphenation patterns for 21 languages loaded.
(/usr/local/texlive/2014basic/texmf-dist/tex/latex/base/article.cls
Document Class: article 2007/10/19 v1.4h Standard LaTeX document class
(/usr/local/texlive/2014basic/texmf-dist/tex/latex/base/size10.clo))
No file a.aux.
(/usr/local/texlive/2014basic/texmf-dist/tex/latex/psnfss/ot1pzc.fd)
kpathsea: Running mktextfm pzcmi7t
/usr/local/texlive/2014basic/texmf-dist/web2c/mktexnam: Could not map source abbreviation  for pzcmi7t.
/usr/local/texlive/2014basic/texmf-dist/web2c/mktexnam: Need to update ?
mktextfm: Running mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input pzcmi7t
This is METAFONT, Version 2.7182818 (TeX Live 2014) (preloaded base=mf)


kpathsea: Running mktexmf pzcmi7t
! I can't find file `pzcmi7t'.
<*> ...=ljfour; mag:=1; nonstopmode; input pzcmi7t

Please type another input file name
! Emergency stop.
<*> ...=ljfour; mag:=1; nonstopmode; input pzcmi7t

Transcript written on mfput.log.
grep: pzcmi7t.log: No such file or directory
mktextfm: `mf-nowin -progname=mf \mode:=ljfour; mag:=1; nonstopmode; input pzcmi7t' failed to make pzcmi7t.tfm.
kpathsea: Appending font creation commands to missfont.log.

! Font OT1/pzc/m/it/10=pzcmi7t at 10.0pt not loadable: Metric (TFM) file not fo
und.
<to be read again>
                   relax
l.5 $\mathpzc{X}
                $
?

PS: It seems I already got psnfss package.

Saits-MacBook-Pro:~ sait$ sudo tlmgr install psnfss
Password:
tlmgr: package repository http://mirrors.rit.edu/CTAN/systems/texlive/tlnet
tlmgr install: package already present: psnfss

Answer 1

It is an X in the mathpzc font:

\documentclass{article}
\DeclareMathAlphabet{\mathpzc}{OT1}{pzc}{m}{it}
\begin{document}

$\mathpzc{X}$

\end{document}