1. U of Iowa CMS group Physics Progress and Plans Jane Nachtman

2. Our Goals Physics at the Energy Frontier
Over the last 20 years, the U Iowa group has positioned itself to extract important physics results from the first LHC data
Calorimetry is crucial in jets and missing ET measurement (hallmark of Supersymmetry)
Forward HCAL (HF) plays a unique role in some signatures, such as VBF Higgs
For many years we prepared for first data
At CERN -- commissioning the HF – combination of hardware and software expertise – analyze cosmic ray data and feed back into hardware improvements
At Fermilab/U of Iowa – studies of cosmic, testbeam data, Remote Operations Center (FNAL), Virtual Control Room(Iowa),simulation studies of New Physics
We have analyzed collision datasets
Lots of exciting physics ahead!

3. Physics Summary Physics analysis with 2010-12 CMS data
Our HCAL expertise is key to understanding Missing ET and forward jet signatures
Forward Jets VBF Higgs
Multi-jet analyses
Jet + MET  Supersymmetry
Dijets  resonances
Majorana neutrino search
Signature-based lljj search
Analysis of CDF dataset
Y(4140) observation
Zgamma analysis
Spectroscopy -- follow up on Y(4140) with CMS data

4. Forward Energy Flow Analysis (Taylan Yetkin, Sercan Sen)
More interactions  more parton radiation in forward region (Phys. Rev. D36 (1987) 2019 & Phys. Rev. D70 (2004) )
Multi-parton interactions not well understood, MC generators need further tuning.
First results for minimum bias and dijets shown at ICHEP 2010, updated with 2011 data
Observed increase in forward energy flow matches theoretical predictions.
Largest systematic error -- detector energy scale uncertainty.

5. Dijet Resonance Analysis (Kai Yi)
PRL 105, , 2010
Dijet Mass Resonance analysis considered among most promising discovery physics searches
UI role – significance studies (fluctuation or new physics)
First public results for ICHEP 2010, updated in 2011,2012
Dijet resonance analysis forms the basis for subsequent Iowa analyses:
Paired dijet resonance
b-tagged dijets
First Exotic Physics publication from CMS!

6. Paired Dijet Resonance (Kai Yi, Maksat Haytmuradov)
Search for colorons (Dobrescu, Kong, Mahbubani, Phys. Lett. B670, 119 (2008))
At least 4 jets (min pt 150), well separated, in final state
Dijet mass matches to 15%

7. Paired Dijet Approved Results
No significant excess found in 2.2/fb
Limits on coloron production between 320 and 580 GeV approved for public presentation Dec 2011
Publication in preparation
expanding coloron search to other channels

8. Missing ET studies for SUSY Searches (Elif Albayrak, Taylan Yetkin)
Calorimeter noise cleanup for Missing ET
QCD Background prediction for SUSY Searches relies on smearing and rebalancing procedures to estimate high Missing ET tails

9. qqH, Hll+MET (Anthony Moeller)
Monte Carlo study for qqH tt  ll+MET
Mass reconstruction methods for the Higgs and backgrounds are being studied.
Uses only final state leptons (e or m) and MET.
Blue – gen., Red – recon.
Before cuts -- background overwhelms signal.
Forward jet tagging should help eliminate backgrounds
forward jets from the VBF process are not common in background processes.

10. Majorana Neutrino Search (Warren Clarida,Emrah Tiras, James Wetzel)
Search for Heavy Majorana neutrino
N can decay to + or – lepton
Same-sign dilepton signature
Jets, no missing ET
Main background is QCD with fake leptons
Limits on mixing element squared versus N mass
No signal – exclusion results with 2.2/fb of 2011 data published (also Warren’s thesis)
2012 data plans – expanding effort with grad students James Wetzel, Emrah Tiras – add channels, improve fake background estimation

11. Observation of Y(4140) at CDF (Kai Yi)
U of Iowa original analysis
Based on B+J/ΨϕK , then search for structures in J/Ψϕ spectrum
Evidence in March 2009, observation in July 2010
Y(4140) NOT likely to be a charmonium (would decay to charm pairs dominantly)
Has fueled lots of theoretical speculation
Possibilities: multiple-quark state, re-scattering, threshold effect,…

12. First CMS Observation of X(3872) (Warren Clarida, Kai Yi)
First-data result, confirm Standard Model, establish CMS for B-physics studies
Observed X(3872) peak with 21 pb-1 of data – presented at APS by Warren Clarida, physics publication
LHCb
CMS

13. Search for Scalar Meson Production (Burak Bilki)
T. Komada et.al., Phys. Lett. B 508, 31 (2001)
Scalar meson existence hypothesized **
Theoretical models: diquark-antidiquark,glueballs,KK
Search y(2S) decays, show variant mass and width method (VMW) today **
I=1/2 states: (or ),
I=1 states: ,
I=0 states: (or ), , , ,

14. Scalar Meson Search
From y(2S), fit the peak and sidebands for signal (s) and pp hypotheses under VMW
Interference effect taken into account
Additionally used Multipole Expansion analysis (a la CDF, BES)
Analysis in progress, expect publication this year

15. CMS Search for structure in J/y f (Kai Yi, Elif Albayrak, Maksat Haytmuradov)
Following CDF experience, seek to confirm Y(4140) and search for more structures in J/y f mass spectrum
Select B+J/ΨϕK -- yield largest exclusive sample to date in the world
Search J/Ψϕ mass spectrum – 2 structures > 5 s
B sample
Results – confirm CDF plus new structure

16. And even more
Our new postdoc, Ping Tan, has recently joined from Fermilab
Brings analysis efforts in W asymmetry measurement and signature-based dilepton+dijet search
Also contributing to our HCAL upgrade simulation effort, along with several of our junior graduate students
See his talk for details
More details on our analysis efforts later with student talks.

17. Publication summary for last three years
CMS Physics publications in refereed journals
Lead authors / major contributions: 7 papers
CMS Physics Analysis Summaries (publically available)
Lead authors /major contributions: 4 papers
CMS detector R&D publications in refereed journals: 7 papers
Internal collaboration publication review committees and institutional review responsibilities: 8 papers on CMS and CDF
CDF Physics publications in refereed journals
Lead authors / major contributions: 1 paper plus one in progress

18. Conclusion
Iowa CMS group physics program focuses on our area of expertise – HCAL  Jet, Forward Physics
We have been major participants in first-data physics results for ICHEP 2010, and with dataset
CMS -- Forward Energy Flow, Dijet Resonance Search, Paired Dijet Resonance, X(3872), SUSY multijets+MET ; CDF – Observation of Y(4140)
We are building our program of jet-based analyses at CMS, in addition leveraging our group’s spectroscopy experience from Tevatron and BaBar
New results Majorana neutrino, B-tagged and Paired Dijets
Discovery analysis in J/ f
The coming years will be very exciting at the LHC!

19. Backup Slides
Details of physics analysis activities

20. Motivation
Acta Phys.Polon.B39: ,2008
More partonic interactions means more central activity, and parton radiation in forward region (Phys. Rev. D36 (1987) 2019 & Phys. Rev. D70 (2004) ) Multi-parton interactions are not well understood, and Monte Carlo generators needs further tuning.
Moreover, the tunes were made by using Tevatron data with |η| < 3.
renormalization scale
(assumed close to the Q2)
Probability of more than one partonic interaction per event increases.

21. Forward Energy Flow Expectation

22. Summary of the Results MinBias Sample Dijet Sample
MinBias Sample
Dijet Sample
As theory predicted, with more partonic interactions in the central region, an increase in forward energy flow was observed.
Main contribution to systematic error comes from detector energy scale uncertainty.

23. Effect of Dead Material
All dead material: Air
Density x 0.5 dead material scenario
Density x 2 dead material scenario
All dead material: Lead
Nominal beam pipe, all other materials
has density changed to x 0.5 and x2
The reason of the reduction of energy flow in high eta comes
from the beam pipe material.

24. Measurement of Jet Resolution from Gamma+Jets Events
Elif Asli Albayrak

25. Motivation
Resolutions will be used in estimation of QCD background for SUSY Jets + Missing Energy channel.
Smear the particle level jets with measured resolution spectrum and apply the complete SUSY analysis on these events.
To mimic particle level jets, rebalance the data events to remove imbalance arising because of resolution effects.
The jets in these seed sample are re-smeared with measured resolutions to estimate the contribution of QCD events to HT or MHT tails.
It is important to measure the complete spectrum of resolution spectrum to correctly estimate the tails due to detector mis- measurements or physics effects (heavy flavor jets)

26. Measuring Resolution: pT Balance Method
intrinsic
(MC truth)
imbalance
independent of second jet pT flat distribution as function of

27. Response Measurements
We measure response in the bins of fraction of PhotonPt carried by the second jet present in the event.
The range we used to estimate resolution for the case where second jet pT extrapolated zero is a part of response measurement uncertainties uncertainties for the following reasons.
Ideal case is to go as low as possible to remain close to the criteria of zero secondary jet activity however lower pT region corresponds to jets below 4-5 GeV where we have a large uncertainty for those jets.
And high fraction deviates as from having back to back two body processes.
To evaluate this source of uncertainty when we measure the ratio between data and MC we used two different ranges where the first on includes low fraction points and the second one remove those low fraction points and add large fraction points.
Nominal values is measured as average of first (low fraction points) and second ratio (large fraction points).

28. How to measure σdata /σMC
Instead of using direct statistical uncertainty in the data/MC ratio, propagating the sensitivity to intrinsic resolution for data and MC before the ratio.
Instead of dividing data by individual MC points
Apply a constant fit to the MC intrinsic measurement.
Divide data points by the fit value
reduce statistical uncertainty comes from MC
Resolutions are measured with two different methods.
Sigma of Gaussian fit
Gaussian fit applied to the +/- 2.5 RMS around mean of measured response
Arithmetic RMS of the response distribution.
Details are only shown for RMS

29. 80 GeV < photon pT < 100 GeV

30. Determining Error Band For Fit Procedure
Extreme V1 : Including low fraction points.
Extreme V2: Including high fraction points.
Nominal = (V1+V2)/2
Log fit applied to Extreme V1 (blue fit) and Extreme V2 (red fit)
The area between Red and Blue curves are accepted as error band.

31. Determining Error Band For JEC
Nominal = Same as previous page.
Log fit applied to the case where we lowered JEC by 5% (blue fit).
Log fit applied to the case where we increased JEC by 5% (red fit).
The area between Red and Blue curves are accepted as error band for JEC.

32. Data/MC with systematic errors
Total systematic uncertainty calculated as quadrature some of yellow and blue error bands.
Because blue bar is small compared the yellow one total systematic uncertainty close to uncertainty comes from JEC.

33. Estimating Tails data/MC ratio is used to stretch MC distributions.
With this way Gaussian core should be same in data and MC.
Then we compared tails and the number of events are counted.
Before MC is stretched.
After MC is stretched.

34. Events In the Tails
Study of resolution spectra in Data and MC in the range outside (0.5 < response <1.5) suggests that there is no significant contribution to the non-Gaussian component in this sample either in Data or MC.
This study will be repeated with reprocessed data and results will be presented with all the systematics

35. Final Step MC Truth will be corrected by data/MC ratio.
Gauss Core
Tails
Corrected MC truth will be used to smear particle level jets to estimate QCD MHT distribution.

36. Update of 2010 Activities
Warren Clarida

37. 21pb-1 Data Compared to 3.1pb-1?
fluctuation or trigger bias
Data (3.1pb-1)
Data (21pb-1)
Monte Carlo
PDG
X(3872) Mass (MeV)
3870.1±2.2
3871.1±1.5
3872.6±0.13
±0.22
X(3872) σ (MeV)
5.52±2.6
6.42±1.1
6.95±1.2
Ψ(2S) Mass (MeV)
3686.3±0.4
3686.2±0.3
3686.5±0.14
±0.04
Ψ(2S) σ (MeV)
4.91±0.39
5.10±0.32
5.24±0.12
Relative Yield X(3872)/Ψ(2S): 76/347 = 0.22±0.06 (3.1pb-1) 143/709 =0.20±0.05 (21pb-1)
November 23, 2018
Warren , CMS QTF Meeting

38. Fit with fixed mass and width (21pb-1)
Null Hypothesis Fit
Signal Hypothesis Fit
sqrt(-2ln(ℒ0/ℒmax)) = 5.57
Where ℒ0 is the likelihood value for the null-hypothesis fit and ℒmax for the signal-hypothesis fit.
We have an observation of the X(3872) at LHC.
We have a more data, but with prescaled triggers this result won’t change much.

39. X(3872) Summary Observed X(3872) peak with 21pb-1 of data. LHCb CMS
November 23, 2018
Warren , CMS QTF Meeting

40. Majorana Study Early process of Majorana Study
Statistics are low, although a preliminary results should be possible.
These pictures show a visualization of a candidate Majorana Neutrino event
November 23, 2018
Warren , CMS QTF Meeting

41. Summary of CDF Research
Kai Yi
University of Iowa
DOE site visit, Dec, 2010

42. Physics Potential at CDF
CDF accumulated large amount of good
data already, do research now.
II. The discovery potential has not been
explored fully, in some area, it is better
than other dedicated experiments
(i.e., the evidence for Y(4140) )
Iowa group service work as guests of Fermilab on CDF: silicon detector operations (Yi) data acquisition expert shifts (Yi) data-taking shifts (Nachtman)

43. Search for new particles-Y(4140)
First reconstruct B+J/ΨϕK+
II. Then Search for structures in
J/Ψϕ spectrum
III. Observed a structure
around their threshold.
Find evidence for an additional
structure about one-pion mass above
the threshold
The mass of Y(4140) is well above the mass threshold of charm pair, it is NOT likely
to be a charmonium. It would decay to charm pairs dominantly if so.
Possibilities: multiple-quark state, re-scattering, threshold effect,…

44. Search for new particles-Y(4140)
Talks related Y(4140) given by Iowa people :
Fermilab Wine & Cheese (Yi)
Moriond QCD (Nachtman)
DIS (Yi)
APS Topical group in Hadron Physics (Yi)
APS (Nachtman)
Charm (Yi)
Iowa Hep seminar (Yi)
DPF (Yi)
Hadron (Yi)
La Tuile (Yi)
QWG (Yi)
ICHEP (Yi)
SLAC experimental seminar (2010) (Yi)

45. CMS Research Played vital role in the first CMS search paper:
Search for new physics through dijet mass spectrum.
Beat Tevatron limit for q* etc.
II. Served as Hcal liaison at CMS PFG group.
III. Co-coordinate HCAL PFG activities
@FNAL
IV. Organized an cross-institution analysis
group to search for puzzling X(3872)
and planning to measure
its cross section. See Warren’s slide for
details.
PRL 105, , 2010