Probing new physics scenarios using high energy events at the NOvA far detector

NuMI Off-axis <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"> <a:msub> <a:mi>ν</a:mi> <a:mi>e</a:mi> </a:msub> </a:math> Appearance (NOvA) experiment is an ongoing long-baseline neutrino oscillation experiment. The primary channels of interest are the <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"> <c:msub> <c:mi>ν</c:mi> <c:mi>e</c:mi> </c:msub> </c:math> , <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"> <e:msub> <e:mover accent="true"> <e:mi>ν</e:mi> <e:mo stretchy="false">¯</e:mo> </e:mover> <e:mi>e</e:mi> </e:msub> </e:math> appearance, <i:math xmlns:i="http://www.w3.org/1998/Math/MathML" display="inline"> <i:msub> <i:mi>ν</i:mi> <i:mi>μ</i:mi> </i:msub> </i:math> , <k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline"> <k:msub> <k:mover accent="true"> <k:mi>ν</k:mi> <k:mo stretchy="false">¯</k:mo> </k:mover> <k:mi>μ</k:mi> </k:msub> </k:math> disappearance channels analyzed in the energy window <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline"> <o:mn>1</o:mn> <o:mo>&lt;</o:mo> <o:msub> <o:mi>E</o:mi> <o:mi>ν</o:mi> </o:msub> <o:mo>&lt;</o:mo> <o:mn>4</o:mn> <o:mtext> </o:mtext> <o:mtext> </o:mtext> <o:mi>GeV</o:mi> </o:math> . However, NOvA far detector sees nontrivial high-energy <q:math xmlns:q="http://www.w3.org/1998/Math/MathML" display="inline"> <q:msub> <q:mi>ν</q:mi> <q:mi>e</q:mi> </q:msub> </q:math> , <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline"> <s:msub> <s:mover accent="true"> <s:mi>ν</s:mi> <s:mo stretchy="false">¯</s:mo> </s:mover> <s:mi>e</s:mi> </s:msub> </s:math> events in the energy range <w:math xmlns:w="http://www.w3.org/1998/Math/MathML" display="inline"> <w:mn>4</w:mn> <w:mo>&lt;</w:mo> <w:msub> <w:mi>E</w:mi> <w:mi>ν</w:mi> </w:msub> <w:mo>&lt;</w:mo> <w:mn>20</w:mn> <w:mtext> </w:mtext> <w:mtext> </w:mtext> <w:mi>GeV</w:mi> </w:math> . These high-energy events provide us with an opportunity to investigate the subleading new physics scenarios. In this context, we study the sensitivity of the NOvA experiment to constrain the nonstandard interaction (NSI) parameters and environmental decoherence parameters. We observe that by including high energy events ( <y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline"> <y:mrow> <y:mi>signal</y:mi> <y:mo>+</y:mo> <y:mtext>background</y:mtext> </y:mrow> </y:math> ) the degeneracy around <ab:math xmlns:ab="http://www.w3.org/1998/Math/MathML" display="inline"> <ab:msub> <ab:mi>ε</ab:mi> <ab:mrow> <ab:mi>e</ab:mi> <ab:mi>τ</ab:mi> </ab:mrow> </ab:msub> <ab:mo>∼</ab:mo> <ab:mn>1.6</ab:mn> </ab:math> can be removed throughout the <cb:math xmlns:cb="http://www.w3.org/1998/Math/MathML" display="inline"> <cb:msub> <cb:mi>δ</cb:mi> <cb:mrow> <cb:mi>C</cb:mi> <cb:mi>P</cb:mi> </cb:mrow> </cb:msub> </cb:math> and <eb:math xmlns:eb="http://www.w3.org/1998/Math/MathML" display="inline"> <eb:msub> <eb:mi>δ</eb:mi> <eb:mrow> <eb:mi>e</eb:mi> <eb:mi>τ</eb:mi> </eb:mrow> </eb:msub> </eb:math> range. Further, we examine the role of signal versus beam background events in removing this degeneracy. In addition, we constrain the decoherence parameter <gb:math xmlns:gb="http://www.w3.org/1998/Math/MathML" display="inline"> <gb:mi mathvariant="normal">Γ</gb:mi> </gb:math> considering events from <jb:math xmlns:jb="http://www.w3.org/1998/Math/MathML" display="inline"> <jb:mrow> <jb:mn>1</jb:mn> <jb:mo>&lt;</jb:mo> <jb:msub> <jb:mrow> <jb:mi>E</jb:mi> </jb:mrow> <jb:mrow> <jb:mi>ν</jb:mi> </jb:mrow> </jb:msub> <jb:mo>&lt;</jb:mo> <jb:mn>20</jb:mn> <jb:mtext> </jb:mtext> <jb:mtext> </jb:mtext> <jb:mi>GeV</jb:mi> </jb:mrow> </jb:math> . Later, assuming the presence of decoherence in nature we obtain the allowed regions in <lb:math xmlns:lb="http://www.w3.org/1998/Math/MathML" display="inline"> <lb:msub> <lb:mi>θ</lb:mi> <lb:mn>23</lb:mn> </lb:msub> </lb:math> and <nb:math xmlns:nb="http://www.w3.org/1998/Math/MathML" display="inline"> <nb:msub> <nb:mi>δ</nb:mi> <nb:mrow> <nb:mi>C</nb:mi> <nb:mi>P</nb:mi> </nb:mrow> </nb:msub> </nb:math> plane.